Dr. Leonard Linkow, one of the pioneers of implant dentistry, once noted that to successfully treat the maxilla with dental implants, new techniques would be required to circumvent maxillary problem areas to establish solid anchorage for fixed restorations.¹ Years later, while seeking alternative anchorage sites for patients with severe maxillary atrophy, the widely recognized father of modern implant dentistry, Dr. Per Ingvar Brånemark, expounded on Linkow’s sentiment, noting “Mother Nature provided an area of dense and extensive bone, near the area of the jaw, which could provide good anchorage prognosis.”² Dr. Brånemark was referring to the zygoma, and a multitude of advancements over the past 35 years have made this a reliable site for establishing prosthetic support in severely atrophic maxillae.³ While zygomatic implants are not new to many in the dental implant community, a number of practitioners continue to remain unaware of this treatment option. As such, the goal of this article is to provide an introduction to zygomatic implants and shed light on the patients who may be appropriate candidates for this treatment modality. 

Background

Since its introduction to dental literature in 2003, the All-on-4 treatment concept has proven to be a predictable and cost-effective method of full-arch dental implant rehabilitation.^4-6 True adherence to this manner of treatment involves restoring an arch with at least 4 dental implants, the distal of which are tilted up to 45°, and immediately loading a screw-retained, provisional prosthesis.^3-5 A number of articles have documented both short- and long-term success rates for All-on-4-style treatment with dental implants and prosthetic survival consistently exceeding 98%.^4,5,7 In the maxilla, extreme sinus pneumatization, premaxillary bone atrophy, low bone density, etc, often create situations where standard All-on-4 treatment becomes challenging, if not impossible. For such patients, zygomatic implants offer same-day, immediate-loading solutions without the need for bone grafting.³ The elimination of bone grafting is a game changer for these patients. In addition to reducing cost, morbidity, and healing time, zygomatic implants have a much higher survival rate than conventional implants placed into large maxillary bone grafts.⁸ As a matter of fact, this was one of the main reasons why Dr. Brånemark and colleagues pursued the development of zygomatic implants.³ Since that time in the late 1980s, zygomatic implant treatment has continuously evolved, and conventional uses of the fixtures have documented survival rates ranging from 94.9% to 96.7%.⁹ These remote anchorage fixtures gain their stability from the robust bone of the zygoma. The zygomatic bone is described as having a “trapezoidal” shape from a lateral view and a narrow inferior base that widens superiorly.^10,11 Mean zygomatic bone height in males is 20.72 mm and 19.66 mm in females. Width ranges from 4.39 mm to 8.10 mm.^11-16 This bone does not atrophy with age nor edentulism and has a composition that routinely averages 80% cortical vs 20% trabecular.^13,14 Potential bone-to-implant contact for zygomatic implants can range from 14.11 to 17.92 mm, and engagement with such a high amount of cortical bone leads to strong insertion torque that regularly exceeds 45 Ncm.^17-22 In cases of severe maxillary atrophy, a single zygoma can withstand the application of multiple fixtures to provide supporting fixation for full-arch prosthetics.^23-25 This fact allows virtually every patient who walks into a dental clinic the option for same-day, immediately loaded maxillary dental implant treatment. 

While zygomatic implants have relatively low complication rates, these maladies can be quite different than those of conventional implants. Intrasurgical complications unique to zygomatic implants include damage to zygomaticofacial and/or infraorbital nerves, zygoma fracture, infratemporal fossa penetration, and orbital violation.^3,25-27 The most common postsurgical issues associated with zygomatic implants are maxillary sinusitis, oroantral fistulas, and transient paresthesia of facial skin.^3,28 The complex nature of zygomatic implant treatment and its possible serious postsurgical complications deem that it should be performed by experienced and highly trained clinicians. While this article is a cursory introduction to zygomatic implants, significantly more information is available in a 492-page textbook I recently published: Remote Anchorage Solutions for Severe Maxillary Atrophy: Zygomatic, Pterygoid, Transnasal, Piriform Rim, Nasopalatine, and Trans-Sinus Dental Implants (available at Amazon). 

CASE REPORTS

Case 1

A healthy, 82-year-old, female patient presented to our clinic with a chief complaint of wanting “permanent” teeth. She had been previously functioning with an implant-supported removable denture for many years. She was not entirely happy with the performance of the restoration due to palatal coverage, taste interruption, speech difficulties, and reduced chewing capacity. Additionally, because the implants were primarily supported by regenerated bone from prior subantral augmentations, the many years of use with a non-rigid, fixated restoration resulted in bone loss around many of the fixtures (Figure 1). Following the induction of general and local anesthesia, a mucoperiosteal flap was achieved, and dissection was performed to expose the zygomatic notches, infraorbital nerves, and piriform rims bilaterally. All pre-existing dental implants were easily removed with implant-retrieval tools via reverse torque application. The remaining maxillary alveolar ridge was extremely thin (Figures 2 and 3) and not conducive to the placement of conventional dental implants. Following the PATZi remote anchorage protocol^3,29 (discussed in detail in the textbook), pterygoid implants were placed initially. Next, zygomatic implants were prepped using an extrasinus protocol to maximize bone-to-implant contact and improve prosthetic screw access positioning. The maxillary sinus was accessed, and the Schneiderian membrane was elevated to access the base of the zygoma. A diamond barrel bur was inserted in the sinus window and used to create a conservative slot (Figure 4), which would guide subsequent osteotomy drills. A series of zygomatic-specific drills was then used with care to intentionally perforate the external zygomatic cortex for the purpose of achieving multi-cortical engagement (Figure 5). Zygomatic depth probing (Figure 6) was utilized to measure zygomatic implant length, and a corresponding fixture was placed following copious irrigation of the surgical site. With the posteroinferior zygomatic implant placed, a second fixture was placed in a similar fashion with care to avoid penetration into the orbital cavity. Both implants achieved extremely high insertion torque, vastly exceeding 60 Ncm. The same procedures were then performed on the contralateral maxilla. Because zygomatic implants, especially quad-zygomatics, are placed at increasingly acute angles, multi-unit abutments of angles up to 60° are required to achieve proper prosthetic positioning (Figure 7). While All-on-X dental literature often cites 120 Ncm of composite torque value as a minimum requirement for success in immediately loaded full-arch dental implant protocols,³⁰ the cumulative insertion torque of the fixtures in this case exceeded 400 Ncm. To reduce the chances of future mucogingival recession exposing the extrasinus portions of the zygomatic implants, buccal fat pad pedicles were advanced to thicken overlying tissues (Figure 8).³¹ Flap closure was achieved using 4-0 chromic gut sutures in Holtzclaw’s Texas 2-Step technique (Figure 9).^1,3 Digital scanning, design, and 3D printing protocols were used to fabricate a screw-retained restoration for immediate loading (Figure 10). Postsurgical CBCT scanning was performed to confirm the proper placement of the remote anchorage fixtures (Figures 11 and 12). 

Figure 1. Presurgical CBCT 3D rendering showing advanced maxillary atrophy.

Figure 2. CBCT scan slice (sagittal view) showing advanced maxillary atrophy.

Figure 3. Maxillary atrophy appreciated following mucoperiosteal flap reflection.

Figure 4. A barrel diamond bur was used to create extrasinus channel preparation to facilitate placement of a zygomatic implant.

Figure 5. An initial marking drill pen- etrated the lateral zygomatic cortex using the extrasinus slot preparation for guidance.

Figure 6. A probing ruler was used to meaure the zygoma osteotomy for determination of the proper fixure length.

Figure 7. Quad-zygomatic and pterygoid implant placement with multi-unit abut- ments of varying degrees was done to achieve harmonious prosthetic paths of draw.

Figure 8. A buccal fat pad pedicle was harvested to cover the extrasinus portions of the zygomatic implant fixtures.

Figure 9. Mucogingival flap closure using Holtzclaw’s Texas 2-Step suturing protocol.

Figure 10. The 3D printed immediate transitional restoration. Note the ideal prosthetic screw access positioning achieved with the PATZi protocol.

Figure 11. Postsurgical CBCT 3D rendering after placement of quad-zygomatic and pterygoid dental implants.

Figure 12. Postsurgical CBCT scan slice (sagittal view) of the right zygoma show- ing fixture engagement in the heart of the bone with ideal spacing between the implants.

Case 2

A 38-year-old male patient was referred to our office for rescue treatment of the maxilla. The patient was originally treated by a dentist who attempted bilateral sinus augmentations and dental implants. Both the implants and the sinus treatments failed, and the patient was ultimately seen by a second dentist. The second dentist treated the issues from the first failed treatments and, after healing, attempted a second round of sinus lifts and dental implants. Unfortunately, the attempt at revision surgery also failed to achieve the desired results for both the dentist and the patient. It was at this point that I was asked to help on this case. Presurgical radiographic evaluation suggested the following: (1) bilateral sinus lifts with xenograft housing axial dental implants, (2) a trans-sinus dental implant on the right side, and (3) two anteriorly placed dental implants engaging the nasal rim (Figure 13). Intraorally, the patient presented with a relatively flat maxilla due to the lack of a premaxillary alveolar ridge. Under-reduction of the maxillary tuberosities created a reverse smile-line situation for the patient (Figure 14). 

Figure 13. Presurgical panoramic radiograph showing pre-existing bilateral maxillary sinus lifts and multiple dental implants displaying varying degrees of success.

Figure 14. Presurgical intraoral condition with a flat anterior maxilla and under-reduced tuberosity.

Figure 15. Condition of the right maxillary sinus upon mucoperiosteal flap reflection. Note the lack of turnover in the bone xenograft/allograft mix.

Figure 16. Despite nearly 6 months of osseointegration, the dental implant in the right grafted sinus was easily removed. Note the dental implant thread pattern in the healing bone graft.

Figure 17. Condition of maxillary sinuses and alveolar ridges following removal of the unincorporated subantral grafts and low-integration dental implants.

Figure 18. A zygomatic implant drill crossing the right maxillary subantral defect.

Figure 19. A probing ruler was used to measure the zygoma osteotomy for determination of proper fixure length.

Figure 20. Zygomatic implant fixture crossing right maxillary subantral defect with achievement of more than 45 Ncm of insertion torque.

After induction of general and local anesthesia, full-thickness mucoperiosteal flaps were elevated to expose the infraorbital nerves, piriform rim, and malar processes. Very large defects were noted in the posterior alveolar ridges at the sites of the previously attempted sinus augmentations. Although the last attempt at sinus graft placement was more than 6 months prior, the xenograft in both sinuses remained unincorporated and had minimal turnover (Figure 15). The axial implants in the graft were freely mobile and easily removed (Figure 16). Likewise, the unincorporated xenograft was also removed with little effort via simple curettage and irrigation. Following the removal of the sinus xenograft, the trans-sinus dental implant only had osseous engagement at the lateral nasal wall. Despite having 6 months of osseointegration, the trans-sinus implant was removed using only 20 Ncm of reverse torque. The anterior implants engaging the nasal rim were solid and had minimal bone loss (Figure 17). Following the PATZi protocol,^3,29 pterygoid implants were first placed bilaterally. The right pterygoid implant was easily placed as the bone in the posterior sinus and the maxillary tuberosity remained relatively intact. This implant achieved more than 50 Ncm of insertion torque. The left pterygoid implant was a bit more challenging due to the more extensive bony destruction in this area. As the osseous defect here extended to the posterior sinus wall, the pterygoid implant directly entered the pyramidal process of the palatine bone via an intrasinus approach. As such, the left pterygoid implant was afforded stability from only the pyramidal process and the pterygoid pillar but still achieved 50 Ncm of insertion torque. Anterior support for the PATZi protocol was already being provided by the previously placed and osseointegrated nasal rim implants. As tilted implants (trans-sinus) had already failed for this patient and minimal bone remained for placement of additional such implants, zygomatic implants were placed next. Entering through the pre-existing sinus defects (Figures 18 and 19), zygomatic implants were placed under copious irrigation. Both zygomatic implants achieved very high insertion torque, exceeding 60 Ncm. Multi-unit abutments were placed to achieve ideal screw access channel locations and torqued to place (Figures 20 and 21). To cover the exposed portions of the extrasinus zygomatic implants and obliterate the residual defects in the maxillary sinuses, large buccal fat pad pedicles were harvested and secured with 4-0 chromic gut sutures (Figure 22). As osseous grafting in the sinuses had failed twice previously in this case, bone grafting was shunned in favor of buccal fat to eliminate dead space. The mucoperiosteal flaps were recontoured with scalpels and 6-0 biopsy punches to accommodate the multi-unit abutments and replaced to their original position with 4-0 chromic gut sutures via Holtzclaw’s Texas 2-Step protocol (Figure 23).^1,3 The patient’s pre-existing denture was then picked up according to the Smart Denture Conversion protocol and converted into a screw-retained transitional bridge. Following delivery to the patient, occlusal adjustment, and a post-surgical CBCT scan (Figure 24), the patient was returned to his referring dentist for completion of restorative treatment.

Figure 21. Zygomatic implant fixture crossing the left maxillary subantral defect with achievement of more than 45 Ncm of insertion torque.

Figure 22. A buccal fat pad pedicle was used to cover the extrasinus portion of the zygomatic implant in addition to obliterating subantral dead space.

Figure 23. Mucogingival flap closure using Holtzclaw’s Texas 2-Step suturing protocol.

Figure 24. Post-surgical CBCT 3D rendering after placement of zygomatic and pterygoid dental implants.

CONCLUSION

Because they engage dense bone in a remote extraoral location unaffected by edentulism-related bone loss, zygomatic dental implants afford nearly all patients the opportunity for maxillary rehabilitation, even under the most severe circumstances. In the cases presented in this paper, without the option of zygomatic implants, these patients would have to endure complicated autogenous bone augmentation procedures, such as iliac crest grafts and the morbidity and healing time that comes with them. While many clinicians may never perform zygomatic implant placement, it behooves them to become educated about this procedure for the sake of their patients.

REFERENCES

1. Holtzclaw D. Pterygoid Implants: The Art and Science. DIA Management Services; 2020.

2. Migliorança RM, Irschlinger AL, Peñarrocha-Diago M, et al. History of zygomatic implants: A systematic review and meta-analysis. Dent Oral Craniofac Res. 2019;5:1-9. doi:10.15761/DOCR.1000289

3. Holtzclaw D. Remote Anchorage Solutions for Severe Maxillary Atrophy: Zygomatic, Pterygoid, Transnasal, Piriform Rim, Nasopalatine, and Trans-Sinus Dental Implants. Zygoma Partners; 2023.

4. Maló P, Rangert B, Nobre M. “All-on-Four” immediate-function concept with Brånemark System implants for completely edentulous mandibles: a retrospective clinical study. Clin Implant Dent Relat Res. 2003;5 Suppl 1:2-9. doi:10.1111/j.1708-8208.2003.tb00010.x 

5. Maló P, Nobre Md, Lopes A. The rehabilitation of completely edentulous maxillae with different degrees of resorption with four or more immediately loaded implants: a 5-year retrospective study and a new classification. Eur J Oral Implantol. 2011;4(3):227–43. 

6. Babbush CA, Kanawati A, Kotsakis GA, et al. Patient-related and financial outcomes analysis of conventional full-arch rehabilitation versus the All-on-4 concept: a cohort study. Implant Dent. 2014;23(2):218–24. doi:10.1097/ID.0000000000000034 

7. Maló P, de Araújo Nobre M, Lopes A, et al. The All-on-4 concept for full-arch rehabilitation of the edentulous maxillae: A longitudinal study with 5-13 years of follow-up. Clin Implant Dent Relat Res. 2019;21(4):538–49. doi:10.1111/cid.12771 

8. Brånemark PI, Gröndahl K, Ohrnell LO, et al. Zygoma fixture in the management of advanced atrophy of the maxilla: technique and long-term results. Scand J Plast Reconstr Surg Hand Surg. 2004;38(2):70-85. doi:10.1080/02844310310023918 

9. Gebretsadik HG. An update on the success rate of the zygomatic implant in Orofacial reconstructive surgery: A 20 years systematic review. Clin Surg J. 2023;4(1):1–6. 

10. Wang H, Hung K, Zhao K, et al. Anatomical analysis of zygomatic bone in ectodermal dysplasia patients with oligodontia. Clin Implant Dent Relat Res. 2019;21(2):310–6. doi:10.1111/cid.12731 

11. Hung KF, Ai QY, Fan SC, et al. Measurement of the zygomatic region for the optimal placement of quad zygomatic implants. Clin Implant Dent Relat Res. 2017;19(5):841–8. doi:10.1111/cid.12524 

12. Xu X, Zhao S, Liu H, et al. An anatomical study of maxillary-zygomatic complex using three-dimensional computerized tomography-based zygomatic implantation. Biomed Res Int. 2017;2017:8027307.doi:10.1155/2017/8027307 

13. Nkenke E, Hahn M, Lell M, et al. Anatomic site evaluation of the zygomatic bone for dental implant placement. Clin Oral Implants Res. 2003;14(1):72–9. doi:10.1034/j.1600-0501.2003.140110.x 

14. Wang H, Hung K, Zhao K, et al. Anatomical analysis of zygomatic bone in ectodermal dysplasia patients with oligodontia. Clin Implant Dent Relat Res. 2019;21(2):310–6. doi:10.1111/cid.12731 

15. Rigolizzo MB, Camilli JA, Francischone CE, et al. Zygomatic bone: anatomic bases for osseointegrated implant anchorage. Int J Oral Maxillofac Implants. 2005;20(3):441–7. https://pubmed.ncbi.nlm.nih.gov/15973956/

16. Saltagi MZ, Schueth E, Nag A, et al. The effects of age and race on calvarium, tegmen, and zygoma thickness. J Craniofac Surg. 2021;32(1):345–9. doi:10.1097/SCS.0000000000006790 

17. Bertos Quílez J, Guijarro-Martínez R, Aboul-Hosn Centenero S, et al. Virtual quad zygoma implant placement using cone beam computed tomography: sufficiency of malar bone volume, intraosseous implant length, and relationship to the sinus according to the degree of alveolar bone atrophy. Int J Oral Maxillofac Surg. 2018;47(2):252–61. doi:10.1016/j.ijom.2017.07.004 

18. Corvello PC, Montagner A, Batista FC, et al. Length of the drilling holes of zygomatic implants inserted with the standard technique or a revised method: a comparative study in dry skulls. J Craniomaxillofac Surg. 2011;39(2):119–23. doi:10.1016/j.jcms.2010.03.021 

19. Balshi TJ, Wolfinger GJ, Shuscavage NJ, et al. Zygomatic bone-to-implant contact in 77 patients with partially or completely edentulous maxillas. J Oral Maxillofac Surg. 2012;70(9):2065–9. doi:10.1016/j.joms.2012.05.016 

20. Lozada G. Use of quadruple zygomatic implants technique for atrophic maxilla rehabilitation with immediate loading—A clinical case report. J Oral Health Dent Sci. 2018;2(2):1-5. doi:10.18875/2577-1485.2.206

21. Dos Santos PL, Silva GH, Da Silva Pereira FR, et al. Zygomatic implant subjected to immediate loading for atrophic maxilla rehabilitation. J Craniofac Surg. 2016;27(8):e734–7. doi:10.1097/SCS.0000000000003063 

22. Bertolai R, Aversa A, Catelani C, et al. Treatment of extreme maxillary atrophy with zygoma implants. Minerva Stomatol. 2015;64(5):253–64. 

23. Bothur S, Jonsson G, Sandahl L. Modified technique using multiple zygomatic implants in reconstruction of the atrophic maxilla: a technical note. Int J Oral Maxillofac Implants. 2003;18(6):902–4. 

24. Duarte F, Ramos C, Silva JN. Immediate function with four zygomatic implants in patients with extreme maxillary atrophy – Case series. J Surg Perio Implant Res. 2019:51-55. doi:10.35252/jspir.2019.1.001.2.01

25. Krauthammer M, Shuster A, Mezad-Koursh D, et al. Extraocular muscle damage from dental implant penetration to the orbit. Am J Ophthalmol Case Rep. 2016;5:94–6. doi:10.1016/j.ajoc.2016.11.008 

26. Bedrossian E, Sullivan RM, Fortin Y, et al. Fixed-prosthetic implant restoration of the edentulous maxilla: a systematic pretreatment evaluation method. J Oral Maxillofac Surg. 2008;66(1):112–22. doi:10.1016/j.joms.2007.06.687 

27. Esposito M, Davó R, Marti-Pages C, et al. Immediately loaded zygomatic implants vs conventional dental implants in augmented atrophic maxillae: 4 months post-loading results from a multicentre randomised controlled trial. Eur J Oral Implantol. 2018;11(1):11-28. 

28. Davó R, Malevez C, Rojas J, et al. Clinical outcome of 42 patients treated with 81 immediately loaded zygomatic implants: a 12- to 42-month retrospective study. Eur J Oral Implantol. 2008;9 Suppl 1(2):141–50. 

29. Holtzclaw D. Treatment of severely atrophic maxillae using the PATZI remote anchorage protocol: a case series. Impl Prac US. 2023;16(4):26-32. 

30. Jensen OT, Adams MW, Butura C, et al. Maxillary V-4: Four implant treatment for maxillary atrophy with dental implants fixed apically at the vomer-nasal crest, lateral pyriform rim, and zygoma for immediate function. Report on 44 patients followed from 1 to 3 years. J Prosthet Dent. 2015;114(6):810–7. doi:10.1016/j.prosdent.2014.11.018 

31. Guennal P, Guiol J. Use of buccal fat pads to prevent vestibular gingival recession of zygomatic implants. J Stomatol Oral Maxillofac Surg. 2018;119(2):161–3. doi:10.1016/j.jormas.2017.10.017 

ABOUT THE AUTHOR

Dr. Holtzclaw is a Diplomate of both the American Board of Periodontology and the International Congress of Oral Implantologists. He served as editor-in-chief of the Journal of Implant and Advanced Clinical Dentistry for 13 years and as an editorial board member and/or editorial reviewer for 6 other dental journals. Dr. Holtzclaw has published more than 60 articles in peer-reviewed journals in addition to writing the dental industry’s first textbook on pterygoid implants. He has provided more than 150 main podium lectures at major dental conferences all over the world and has been named a “Leader in Continuing Dental Education” by Dentistry Today for the past 20 consecutive years. Currently, Dr. Holtzclaw serves as the director of fixed-arch solutions for the Affordable Care Network of dental clinics, a dental service organization with 400-plus clinics in 42 states. He maintains a limited practice specializing in same-day, full-arch implant dentistry utilizing zygomatic, pterygoid, and standard dental implants. He can be reached at dan.holtzclaw@advancedimplants.com. 

Disclosure: Dr. Holtzclaw reports no disclosures. 

Historically, everything from autogenous bone to xenografts, allografts, and alloplastic materials has been used and studied in dentistry when a graft or graft substitute is needed. These different materials have all been used with great success over the years, and they continue to provide clinically successful results. The alloplastic class over the years has become an exciting class since it is continually being advanced at a greater rate by new products than the allograft and xenograft classes.

Everyday, practitioners are faced with the need to graft and regenerate new bone. This can be an extraction site, an existing defect, or in combination procedures such as immediate implant placements or sinus elevations. The purpose of a graft material is to not only maintain clinical bone volume but also also to provide a framework for new bone growth as the particles are resorbed for new bone regeneration. Only in the case of an autograft will osteogenesis occur, as there are live cells capable of proliferating to create new bone. Therefore, a bone substitute is a natural or synthetic material, often containing only a mineralized bone matrix with no viable cells.¹ 

In studies, the 3 main classes of graft materials (allograft, xenograft, and alloplast) all showed the presence of newly formed bone with residual graft particles and connective tissue in greater or lesser amounts. The presence of newly formed bone in direct contact with residual particles of each bone substitute material indicated the adequate osteoconductive capacity.² 

This article will compare the makeup and advantages/disadvantages of the materials noted above and then focus on a material consisting of non-ceramic, synthetic, bioactive resorbable calcium apatite crystals known as OsteoGen (IMPLADENT LTD). These hydrophilic cluster particulates have physicochemical and crystallographic properties similar to human minerals. The low-temperature, bioactive calcium phosphate mineral also has the ability to control the migration of connective tissue.³ 

We are now going to look at and compare individual classes of graft materials to better understand the advantages of OsteoGen.

AUTOGENOUS BONE

Autografts remain the gold standard for grafting materials as they are still the only graft material that possesses the 4 fundamental biological properties required for bone regeneration, but they are not without issues.^1,4

An advantage of the use of autogenous bone graft materials is that they represent the highest degree of biological safety, and there are no histocompatibility or immunogenicity issues associated with their use.

Even with autogenous bone grafts being considered the optimal choice for augmentation, the procedure usually requires harvesting bone from a distant donor site. This resulting second site morbidity can, has, and will continue to lead to patient dissatisfaction. 

ALLOGRAFTS

Allograft materials, which are derived from cadaveric sources, have been used for decades with great success. These materials come in many forms, including mineralized and demineralized particulates and puttys. They are also available in cortical and cancellous formulations or a blend of the 2.

On their own, cancellous autografts and allografts have poor mechanical strength in addition to exhibiting inadequate healing capacity. The tissue-processing techniques, including treatment with alcohol, acetic acid, or nitric acid, reduce the materials’ osteoinductive capabilities.^1,5 These graft materials can also cause local host inflammatory responses, which can result in fibrous tissue formation rather than healthy bone. This is of concern and can produce up to 62% connective tissue, which is not conducive to good implant support after load (Figure 1).

Figure 1. Four clinical studies of allografts (mineralized or demineralized) conducted at New York University College of Dentistry and the University of Texas San Antonio from 2002 to 2012.

Cortical particles, on the other hand, do provide structural support and provide a mineral storehouse, but these take longer to resorb. This increased resorption time is a distinct advantage when trying to either rebuild height/width or maintain osseous architecture when thin cortical plates are present after an extraction. 

The downside, a common issue with all types of particulate grafts, is the possibility of migration or loss of material. Even if the particles are bound, as in bone putty by a binder, the addition of fluids, including blood, can wash these products out during clinical delivery. Finally, the literature supports the possibility of disease transmission by this class of products.⁶ 

Caution: Not all mineralized graft materials are the same.

ALLOPLASTS 

Historically, many substances have been used as components for grafting in dentistry, either by themselves or as a binder with other graft materials. This author has used many of these with varying results. Calcium phosphate is one substance that has been used as a bone cement either to deliver antibiotics locally or to bind allograft or xenograft particulates. One example of this type of product is Fusion Bone Binder (Park Compounding Pharmacy). Bi-phasic calcium phosphate products such as Augma Biomaterials’ 3D Bond (Augma Biomaterials) and Bond Apetite are products that are used alone as a graft material. Beta-tricalcium phosphate (β-TCP) products such as Cerasorb M (Curesan) is another material used alone to graft sockets or defects around implants. 

DENSE SINTERED ALLOPLASTS AND XENOGRAFTS

The Food and Drug Administration refers to dense, non-resorbing products as bone filler and augmentation materials (BFAM), and these have been used extensively for many years. To overcome potential immunogenicity and morbidity at donor sites, artificial synthetic bone substitutes and natural materials are manufactured to closely mimic the biological properties of natural bone.¹ These alloplast materials are either derived from natural substances (ie, coralline) or man-made and can be a homogenous product or a mix of materials. A variety of synthetically and organically derived dense bone formulations have been used in dentistry and medicine. In dentistry, they are used for the therapeutic repair and restoration of osseous ridge defect sites, post-tooth extraction (including periodontal reconstruction), sinus augmentation with and without implants, and post cyst removal with questionable results. Since these products have weak regenerative abilities on their own, highly sintered alloplastic and organic bone substitutes are often augmented with growth factors and membranes at an increased cost to the practitioner.

When evaluating the rates of resorption of ceramic hydroxyapatite (HA) alloplastic materials, the results are questionable. Densely sintered at high temperatures, pure ceramic HA has low microporosity and high density and is prepared in relatively large particle size with long resorption times. Essentially, these materials closely resemble ceramics. Sintered (non-resorbable) HA materials,⁷ xenografts, and allografts are often subject to fibrous tissue encapsulation rather than becoming a viable part of the host bone.⁸ 

Upon tooth extraction, the goal is complete regeneration while preventing pathology from arising that could signal the patient’s immune response against getting involved, depending upon the type of graft material used. One consequence is the involvement of macrophage cells. In extraction sites where dense products such as ceramic HA, TCP, glass, polymers, coralline, and xenografts are placed, these macrophages are recruited. This is in contrast to the normal mechanism of osteoclastic breakdown. 

These cells are signaled by an immune response to remove the graft material as foreign matter, and these 18-µm cells will continue to enter the socket area through the nutrient canals in the lamina dura (Figure 2).

Figure 2. The tooth-alveolous construct.

This immune response is inevitable in the use of these products, and the immune system’s mechanism is to eventually produce multi-nucleated giant cells to fragment (not phagocytose) these dense graft materials and transport the residual pieces to larger filters in the body (ie, lymph nodes, lungs, and the spleen), resulting in the patient’s compromised immune system.^9,10

Studies have shown that highly dense bovine xenografts have also been shown to induce the formation of giant cells relatively early in the healing process.¹¹ 

Compared with allogeneic and xenogenic bone grafts, common advantages of non-resorbable alloplastic bone substitutes are the standardized product quality and absence of infectious disease risk. The main advantages of alloplastic non-resorbing bone substitutes involve their biological stability and volume maintenance, which allow cell infiltration and remodeling.¹² Originally HA ceramic and β-TCP products comprised 80% of all alloplastic bone graft products in the market. 

Xenografts can be derived from sources including bovine and porcine origins, with bovine being the most prominent graft source in the industry. Xenografts carry with them the potential for immunologic reaction resulting in the patient mounting a host immune response against the grafting material. The long-term clinical use and safety of xenografts and their potential association with severe immune responses, as well as objections to their use for both religious and ethical reasons, are valid concerns.

Dental literature has rarely addressed the clinical risks and complications of anorganic bovine bone as a grafting material. However, the scarce literature on complications does not mean that such events are unusual. Often, the negative findings are not published or are not being submitted for publication in dentistry; ignoring the negative outcomes is worrisome as it skews the scientific literature. To the authors, a major concern was the late complications caused by product not resorbing, extending from 2 to 13 years after what was considered to be a successful treatment outcome. In the study, adverse effects presented in the case series report included sinus and maxillary bone pathoses, displacement of the graft materials, oroantral communications, implant failure, foreign body reactions, encapsulation, chronic inflammation, soft-tissue fenestrations, and associated cysts.¹³

Finally, the amount of time it takes for full “resorption” of the bovine xenograft material is a potential issue due to the fragmentation of the particulate by multi-nucleated giant cells, which is of immunologic concern. Human biopsies after sinus augmentation confirm that particles of bovine-derived bone substitutes can still be found up to 10 years postoperatively.¹⁴

RESORBABLE CALCIUM APATITE CRYSTALS AND CLUSTERS

OsteoGen has been used as a particulate graft material since 1984 and has documented clinical success for use with implants, general osseous repair,¹⁵ periodontal procedures,¹⁶ and sinus lifts.¹⁷ When first developed and brought to market, OsteoGen crystals and clusters were used either alone or mixed with other graft materials to extend the amount of graft and to enhance new bone growth. Over the years, product development to address the needs of practitioners has driven new products that contain the OsteoGen crystals mixed with highly purified Achilles tendon collagen. These products include OsteoGen Plugs, OsteoGen Strips, OsteoGen Blocks, and OsteoGen Plates (Figure 3).

Figure 3. Available OsteoGen (IMPLADENT LTD) products.

The bioactive crystal is grown utilizing a unique low-temperature production process that generates osteoconductive and resorbable low-density crystals and crystal clusters (Figure 4). It has a unique calcium-to-phosphate ratio similar to human bone that is neither a β-TCP nor a dense, non-resorbable ceramic HA. 

Figure 4. Scanning electron micrograph of the OsteoGen crystal.

Figure 5. A 3-month histology by Dr. Kyle Hale at the University of Texas Health and Science Center.

As discussed previously, a non-autogenous bone graft material should ideally be non-antigenic, bioactive to control migration of connective tissue, osteoconductive, and synthetically derived with a clinically acceptable time frame of resorption of the majority of such material (Figure 5). The material does have physicochemical and crystallographic properties relatively similar to the host bone (Figure 6) and possesses a bioactive resorptive chemical potentiality to induce favorable cellular response for new bone formation by the action of ionization into calcium and phosphate ions in a chemotactic state.³ What this means is that the breakdown of the clusters produces the optimal environment on a cellular level for bone regeneration. 

Figure 6. A fractured cross section of OsteoGen bioactive crystal with similarity to natural bone.

The clusters are a highly microporous, non-sintered, non-ceramic material composed of small and large crystals and hydrophilic clusters with a controlled, predictable rate of resorption based on the patient’s age and metabolism. 

As opposed to particulate grafting materials on the market today, the plugs and strips prevent the migration of the OsteoGen crystals from the recipient’s surgical site by binding the crystals with collagen. With an approximate ratio of 60/40 mineral to collagen, it is similar to the makeup of native bone, and the distribution of OsteoGen crystals to porous collagen matrix creates an environment conducive to angiogenesis, cell proliferation, and new bone growth. The bioactive definition relates to the nature of the graft’s ability to form new bone by controlling migration of connective tissue and releasing calcium ions to stimulate new bone formation.

One of the main advantages of OsteoGen bioactive crystals is the ability to provide Ca⁺ ions directly into the site where bone growth and maturation will occur. When the composite is fully saturated with blood, these ions are released at an optimal level to facilitate healthy bone regeneration. 

Local Ca⁺ levels in the grafted area control osteoblastic viability, proliferation, and differentiation and are concentration-dependent.

• Too high: >10mM results in apoptosis.
• Optimum: 6 to 8mM results in proliferation.
• Too low: 2 to 4mM results in proliferation and survival without differentiation.

Various clinical studies and recently published papers have confirmed OsteoGen’s bioactivity.

In a split-mouth study conducted by Yosouf et al,¹⁸ it was shown that, when compared to healing without a graft (control), ridge preservation was greatly enhanced by the use of an OsteoGen Plug. Results showed a 60% improvement when grafting with an OsteoGen Plug as 0.56 mm was lost vertically with the plug compared to 1.47 mm lost in the control. When looking at horizontal grafting, 0.9 mm was lost horizontally compared to 2.26 mm in the control. This minimal amount of bone loss is comparable to levels lost when utilizing an allograft and a membrane,¹⁹ although Yosouf et al¹⁸ achieved these results with the use of a Plug alone and no membrane. 

Jones et al²⁰ directly compared an OsteoGen Plug to a Collagen Xenograft Plug (Salvin Dental Specialties) and human bone allograft. It was found that osteoblast proliferation throughout the OsteoGen Plug was between 3 and 6 times greater compared to the xenograft plug or allograft. Additionally, live cell images showed significantly greater osteoblast activity at multiple time periods compared to the xenograft material, which could not sustain the cells. Also, this study showed significantly higher porosity levels (94.4%) for the OsteoGen Plug compared to xenograft material (75.2%) and allograft (55.8%). The study concluded that the OsteoGen Plug demonstrated significantly better biocompatibility compared to the xenograft option and the allograft option alone. 

Jafarian²¹ compared the bone quality attained when using an OsteoGen Plug without a membrane to the bone quality attained using Biohorizons’ MinerOss corticocancellous allograft particulates and a dense PTFE membrane. The author concluded that there was no significant difference in bone quality measured by histomorphometry for placing an implant at 3 to 5 months between the OsteoGen Plug without a membrane and the current gold standard of corticocancellous allograft covered with a membrane.²⁰

The following case series will reinforce the literature with regard to the uses and results of this alloplast plug.

RIDGE PRESERVATION

The most common observation of insufficient quantity of bone in dentistry is following tooth loss, where rapid resorption of alveolar bone occurs due to an absence of intraosseous stimulation that would typically occur via the periodontal ligament fibers.^1,22,23 The amount of resorption is greatly dependent upon the reason for the extraction and the length of time pathology has been present. Studies and anecdotal clinical evidence provide the rationale for grafting fresh extraction sockets. 

During the first year after tooth loss, a patient can see possibly 40% to 60% of the width and height of the alveolar ridge resorb after tooth extraction. Preserving the alveolar ridge offers patients choices in their restorative treatment plans, including endosseous implants.²⁴

All successful ridge preservations have a common starting point, and that is the atraumatic extraction.²⁵ There are a plethora of instruments available, and practitioners use just as many techniques to remove teeth. Though the specific techniques to achieve this will not be discussed in detail, the result by the use of any instrument or technique should minimize soft- and hard-tissue trauma.

SOCKET PRESERVATION CASE 

The patient presented with a non-restorable maxillary right second molar (Figure 7a). Although the patient would likely not suffer any functional deficiency when chewing, he chose to have the site grafted in order to keep the possibilities open for an implant placement at a later date. After sectioning the roots for a less traumatic extraction (Figure 7b), the individual roots were removed while being careful not to damage the buccal plate (Figure 7c).

Figure 7. Socket preservation case.

Once the roots were removed, the sockets were thoroughly debrided to not only clean out any granulation tissue but also to produce copious bleeding. This bleeding is extremely important to kick off healing through what is known as the Regional Acceleratory Phenomenon by making holes through the lamina dura into cancellous bone and recruiting osteoclast cells. The OsteoGen Plug was then cut with scissors (Figure 7d) into a 3-root-like plug and placed into the socket (Figure 7e). The blood was allowed to soak into the plug by compacting the plug very gently into the socket to allow it to conform to the site (Figure 7f). A figure 8 chromic gut suture was utilized to hold the plug in place (Figure 7g). A primary closure or use of a membrane was not necessary. The compacted plug creates a bioactive-crystal, “wall-like” membrane to control the downward migration of connective tissue. 

A radiograph taken immediately post-op showed that the plug itself was radiolucent (Figure 7h) and would become more radio-opaque as it was replaced by native bone. This unique aspect allows a practitioner to easily know when the site is ready for further treatment.

An intraoral photo of the site at one month demonstrates the complete closure of the site by secondary healing (Figure 7i). The 3.5-month radiograph is indicative of how the socket radio-opacity changes during healing by showing bony reconstruction of the socket (Figure 7j).

GRAFTING THE GAP WITH IMMEDIATE IMPLANT PLACEMENT

Much has been written regarding how to manage the “gap” that results when an implant is placed in an extraction socket. When a dental implant is placed into a fresh extraction socket, the space between the implant periphery and surrounding bone is called the “gap” or “jumping distance.” Bone filling in the gap between the implant and the peripheral bone is important for integration and long-term success. The buccal aspect of an implant is of great concern, especially in the aesthetic zone, because the buccal bony plate is usually thin, and its resorption can result in soft-tissue recession.¹⁷

The horizontal gap, if less than 2 mm, will likely fill in without any intervention by the practitioner. In fact, it has been shown that it is possible to have complete fill-in with a gap of up to 4.2 mm, but this is not predictable. Due to this unpredictability, grafting the gap is a belt-and-suspenders approach to assuring that both hard and soft tissue remain stable through the healing process and result in the optimal aesthetics when treatment is completed.²⁶ 

In 2012, Chu et al²⁷ showed that the most predictable hard- and soft-tissue changes and aesthetic results when immediately placing implants in a fresh extraction socket occurs when the gap between the implant and the alveolus is grafted. 

IMMEDIATE PLACEMENT CASE 

Presenting with a failing maxillary right central (Figure 8a), this patient opted for extraction and immediate placement of an implant. After an atraumatic extraction of the tooth (Figure 8b), the tooth was evaluated to determine the amount and position of graft material to be placed. By laying an osteotomy bur on the root, this calculation is very easy to perform (Figure 8c).

Figure 8. Immediate placement case.

The osteotomy was prepared following standard protocol to ensure proper prosthetic position, and the site was checked for any inadvertent perforation. A portion of an OsteoGen Strip was rehydrated with sterile saline in preparation for use. As opposed to the plug, which is delivered dry into an extraction socket, the OsteoGen Strip is rehydrated beforehand to enhance its moldability to fill the gap between the implant body and the alveolus (Figure 8d). 

The position of the implant preparation had been distalized to take advantage of bone contact on the distal wall of the socket and to place the long axis of the implant in the correct prosthetic position for a central incisor with a midline diastema (Figure 8e). After placement of the strip, the implant was driven into place, causing the moldable strip to fill in any gaps (Figure 8f). Placing the strip first will be easier in these kinds of cases rather than trying to place it after the implant is in place. A check film was taken to verify the position (Figure 8g) and show the area of graft placement in the remaining socket. A 3-mm-tall healing abutment was placed, and the site was sutured with PGA sutures (Figure 8h). At the time of placement, the stability was not at a level that would have allowed for direct, immediate temporization. 

After 3.5 months of healing, the healing abutment was removed (Figure 8i), a digital impression post was placed, and the site was scanned for the final restoration. A custom titanium abutment with a full zirconium restoration was chosen for the final restoration and delivered a few weeks later (Figure 8j). The soft-tissue quantity and quality was excellent, and the patient was pleased with the outcome. 

SINUS ELEVATION

Everything from autogenous bone to allografts, xenografts, and alloplasts has been successfully used as graft material in the sinus. The osteoconductive activity of various bone substitutes has been assessed according to the quality and quantity of newly formed bone in the augmented areas.^28,29

The successful use of OsteoGen crystals in sinus elevation has been well-established for more than 30 years. In 1991, Wagner³⁰ showed the efficacy of this material in a 3.5-year follow-up study, and Manso and Wassal¹⁷ expanded on this work with a 10-year longitudinal study.The introduction of OsteoGen Plugs and Strips simplifies both vertical and lateral approach subantral lifts. The issues of material migration due to settling or loss due to the presence of a perforation have been mitigated due to the collagen makeup of the products. 

The use of these products as a graft material is independent of the type of lift or technique used. Either plugs, strips, or malleable OsteoGen blocks can be used depending on the clinical situation. This author prefers to use plugs for vertical lifts and strips for lateral approach lifts. 

SUBANTRAL AND LATERAL SINUS LIFTS 

In this case, the sinus floor needed a sub-5-mm lift to accommodate the apex of the implant to be placed (Figure 9a). An osteotome was used to up-fracture the floor after creating an osteotomy approximately 1 mm short of the sinus floor. A regular-size OsteoGen Plug (Figure 9b) was cut to the appropriate dimension needed for the lift (Figure 9c) and placed into the osteotomy using an osteotome (Figure 9d). The resulting lift showed a smooth membrane without any indications of a tear (Figure 9e). With the use of these plugs, even if there was a small perforation or tear, the plug would allow for healing of the Schneiderian membrane without loss of the graft. 

The Caldwell-Luc procedure, or lateral approach lift, is used when the clinical amount of crestal bone is less than 3 to 4 mm and placement of an implant would result in very little stability or exposure into the sinus cavity. The use of OsteoGen Strips rather than plugs to graft this type of case was decided upon in order to allow better conforming to the walls of the sinus cavity. 

Figure 9. Sinus elevation cases.

In this case, the sinus had pneumatized after extraction of the maxillary right first molar (Figure 9f) and required a lift of approximately 10 mm to accommodate the length of the intended implant to be placed. 

After a window was cut in the lateral wall of the sinus with a #2 round diamond (Figure 9g), the OsteoGen Strips were soaked in sterile saline (Figures 9h and 9i) to rehydrate them and make them malleable. Strips are first placed against the medial wall, then superiorly (Figure 9j), anteriorly, and posteriorly. This ensures that there will be grafting material 360° around the implant (Figures 9k and 9l) prior to placing additional strips laterally.

The final radiograph, taken 4 months later, indicated the growth of bone around the implant and the successful lift (Figure 9m). 

CONCLUSION

Many times, it is a patient preference or refusal of a material that will guide a practitioner toward the type of grafting material he or she can use in a case. Studies have shown the highest rate of refusal was observed for allografts and xenografts. The grafts with the lowest rates of refusal were autologous grafts (3%) and dense alloplastics (2%).³¹ 

An advanced composite graft material such as OsteoGen, in all its prefabricated shapes and formulations, has the advantages of ease of use, cost-effectiveness, clinical ease of delivery, and adaptability to its intended site when compared to the other grafting particulate options on the market today. It is a viable and, in many circumstances, a better long-term option for grafting than traditionally used xenografts and allografts. 

Currently, and in the future, combining this product with growth mediators such as PRF or other substances will open new chapters of outstanding clinical results. It is very likely that, in the future, the use of allografts and xenografts will likely diminish, and alloplastic bioactive materials, which have high quality, safety, and ease of clinical delivery, will be the regenerative materials of choice.

REFERENCES

1. Zhao R, Yang R, Cooper PR, et al. Bone grafts and substitutes in dentistry: a review of current trends and developments. Molecules. 2021;26(10):3007. doi:10.3390/molecules26103007
2. Nappe C, Rezuc A, Montecinos A, et al. Histological comparison of an allograft, a xenograft and alloplastic graft as bone substitute materials. J Osseointegration. 2016;8(2):20–6. doi:10.23805/jo.2016.08.02.02
3. Valen M, Ganz SD. A synthetic bioactive resorbable graft for predictable implant reconstruction: part one. J Oral Implantol. 2002;28(4):167–77. doi:10.1563/1548-1336(2002)028<0167:ASBRGF>2.3.CO;2
4. Misch CM. Autogenous bone: is it still the gold standard? Implant Dent. 2010;19(5):361. doi:10.1097/ID.0b013e3181f8115b
5. Roberts TT, Rosenbaum AJ. Bone grafts, bone substitutes and orthobiologics: the bridge between basic science and clinical advancements in fracture healing. Organogenesis. 2012;8(4):114–24. doi:10.4161/org.23306
6. Simonds RJ, Holmberg SD, Hurwitz RL, et al. Transmission of human immunodeficiency virus type 1 from a seronegative organ and tissue donor. N Engl J Med. 1992;326(11):726–32. doi:10.1056/NEJM199203123261102
7. Linkow LI. Bone transplants using the symphysis, the iliac crest and synthetic bone materials. J Oral Implantol. 1983;11(2):211–47.
8. Toloue SM, Chesnoiu-Matei I, Blanchard SB. A clinical and histomorphometric study of calcium sulfate compared with freeze-dried bone allograft for alveolar ridge preservation. J Periodontol. 2012;83(7):847–55. doi:10.1902/jop.2011.110470
9. Ahmadzadeh K, Vanoppen M, Rose CD, et al. Multi-nucleated giant cells: current insights in phenotype, biological activities, and mechanism of formation. Front Cell Dev Biol. 2022;10:873226. doi:10.3389/fcell.2022.87322
10. Miron RJ, Zohdi H, Fujioka-Kobayashi M, et al. Giant cells around bone biomaterials: Osteoclasts or multi-nucleated giant cells? Acta Biomater. 2016;46:15-28. doi:10.1016/j.actbio.2016.09.029
11. Barbeck M, Udeabor SE, Lorenz J, et al. Induction of multi-nucleated giant cells in response to small-sized bovine bone substitute (Bio-Oss) results in an enhanced early implantation bed vascularization. Ann Maxillofac Surg. 2014;4(2):150–7. doi:10.4103/2231-0746.147106
12. Fukuba S, Okada M, Nohara K, et al. Alloplastic bone substitutes for periodontal and bone regeneration in dentistry: current status and prospects. Materials (Basel). 2021;14(5):1096. doi:10.3390/ma14051096
13. Rodriguez AE, Nowzari H. The long-term risks and complications of bovine-derived xenografts: A case series. J Indian Soc Periodontol. 2019;23(5):487–92. doi:10.4103/jisp.jisp_656_18
14. Piattelli M, Favero GA, Scarano A, et al. Bone reactions to anorganic bovine bone (Bio-Oss) used in sinus augmentation procedures: a histologic long-term report of 20 cases in humans. Int J Oral Maxillofac Implants. 1999;14(6):835–40.
15. Wagner JR. Clinical and histological case study using resorbable hydroxylapatite for the repair of osseous defects prior to endosseous implant surgery. J Oral Implantol. 1989;15(3):186–92.
16. Epstein SR, Valen M. An alternative treatment for the periodontal infrabony defect: a synthetic bioactive resorbable composite graft. Dent Today. 2006;25(2):92–7.
17. Manso MC, Wassal T. A 10-year longitudinal study of 160 implants simultaneously installed in severely atrophic posterior maxillas grafted with autogenous bone and a synthetic bioactive resorbable graft. Implant Dent. 2010;19(4):351–60. doi:10.1097/ID.0b013e3181e59d03
18. Yosouf K, Heshmeh O, Darwich K. Alveolar ridge preservation utilizing composite (bioceramic/collagen) graft: A cone-beam computed tomography assessment in a randomized split-mouth controlled trial. J Biomed Eng. 2021;14(2):64-73. doi:10.4236/jbise.2021.142007
19. Cheon GB, Kang KL, Yoo MK, et al. Alveolar ridge preservation using allografts and dense polytetrafluoroethylene membranes with open membrane technique in unhealthy extraction socket. J Oral Implantol. 2017;43(4):267–73. doi:10.1563/aaid-joi-D-17-00012
20. Jones K, Williams C, Yuan T, et al. Comparative in vitro study of commercially available products for alveolar ridge preservation. J Periodontol. 2022;93(3):403–11. doi:10.1002/JPER.21-0087
21. Kumar P, Vinitha B, Fathima G. Bone grafts in dentistry. J Pharm Bioallied Sci. 2013;5(Suppl 1):S125–7. doi:10.4103/0975-7406.113312
22. Misch CE, Dietsh F. Bone-grafting materials in implant dentistry. Implant Dent. 1993;2(3):158–67. doi:10.1097/00008505-199309000-00003
23. Murray VK. Anterior ridge preservation and augmentation using a synthetic osseous replacement graft. Compend Contin Educ Dent. 1998;19(1):69-74, 76–7.
24. Schlesinger C. Ridge preservation technique: there’s more than one way to fill the hole! Dent Today. 2019;28(3)42-27.
25. Schlesinger C. A novel approach to grafting around implants. Dent Today. 2017;26(12):50-54.
26. Chu SJ, Salama MA, Salama H, et al. The dual-zone therapeutic concept of managing immediate implant placement and provisional restoration in anterior extraction sockets. Compend Contin Educ Dent. 2012;33(7):524–32, 534.
27. Berberi A, Nader N, Noujeim Z, et al. Horizontal and vertical reconstruction of the severely resorbed maxillary jaw using subantral augmentation and a novel tenting technique with bone from the lateral buccal wall. J Maxillofac Oral Surg. 2015;14(2):263–70. doi:10.1007/s12663-014-0635-7
28. Artzi Z, Nemcovsky CE, Tal H, et al. Histopathological morphometric evaluation of 2 different hydroxyapatite-bone derivatives in sinus augmentation procedures: a comparative study in humans. J Periodontol. 2001;72(7):911–20. doi:10.1902/jop.2001.72.7.911
29. Wagner JR. A 3 1/2-year clinical evaluation of resorbable hydroxylapatite OsteoGen (HA Resorb) used for sinus lift augmentations in conjunction with the insertion of endosseous implants. J Oral Implantol. 1991;17(2):152–64.
30. Fernández RF, Bucchi C, Navarro P, Beltrán V, Borie E. Bone grafts utilized in dentistry: an analysis of patients’ preferences. BMC Med Ethics. 2015;16(1):71. doi:10.1186/s12910-015-0044-6

ABOUT THE AUTHOR

Dr. Schlesinger has been placing implants for the past 28 years, and as an educator for the past 19 years, he has taught doctors worldwide about dental surgical procedures. Along with running a busy private practice in Rio Rancho, NM, he maintains a clinical advisory role with numerous dental product manufacturers. He can be reached at  cdschlesinger@gmail.com. 

Adj. Prof. Valen is the founder and CEO of Impladent. He can be reached at maurice@impladentltd.com. 

Disclosure: Dr. Schlesinger is a paid consultant for Impladent. Mr. Valen is a nonpaid consultant for Solmetex and CEO of Impladent.

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Implant dentistry has become a discipline in health care to reconstruct lost soft and hard tissues to facilitate dental rehabilitation. Endosseous implants demonstrate high success rates when placed in an adequate volume of bone.¹ Bone resorption is a common sequel after the loss of a tooth.² Tooth loss is a result of caries, trauma, periodontal disease, perio-endo lesions, or congenitally missing teeth. Several approaches to managing alveolar ridge deficiency have been described, including ridge expansion, guided bone regeneration (GBR), and autogenous and allogenic block grafting.^3-5 

Autogenous block grafts are considered the gold standard approach for bone grafting because they provide osteogenic, osteoinductive, and osteoconductive properties.⁶ This source of bone can be procured from intraoral sites, such as the mandibular symphysis, ramus, or maxillary tuberosity. Extraoral sites can be utilized for larger recipient areas harvested from the iliac crest, calvarium, or tibia. The limitations of autogenous block grafting are morbidity, limited quantities, resorption potential, and a high skill level needed by the clinician.⁷ 

Allographic block grafting has gained wide acceptance because of reduced morbidity and unlimited availability if a large quantity of bone is needed.⁸ Allogenic grafts may be utilized in a particulate or block form, depending on the nature of the surgical objective. There is evidence of high success rates of graft integration with minimal resorption. In addition, implants placed into allogenic bone have demonstrated high survival rates.^9,10 

This case report discusses the management of a congenitally missing maxillary lateral incisor with a horizontal alveolar ridge deficiency. A staged approach encompassing an allogenic block graft followed by implant placement and prosthetic reconstruction was employed. This technique is for consideration for horizontal ridge augmentation for dental implant reconstruction.

CASE REPORT

A 21-year-old female patient presented to my office with an edentulous space associated with the maxillary right lateral incisor (tooth No. 7). The patient’s history revealed that the tooth was congenitally missing, and orthodontic therapy was completed 10 years ago. The medical history revealed no significant findings except for the daily intake of the medication Escitalopram (Lexapro) to manage episodes of depression. The clinical and radiographic examination revealed a Class I occlusion, adequate keratinized gingiva, and a deficiency in the buccal-palatal alveolar ridge (Figures 1 to 3). A diagnosis of horizontal ridge atrophy was made. The agreed-upon treatment plan was endosseous implant therapy post allogenic block grafting in a staged approach.

Figure 1. Presurgical site, maxillary right lateral incisor (tooth No. 7).

Figure 2. Buccal-palatal deficiency.

Figure 3. CBCT image, section view.

The surgical phase was initiated with a 20-mL blood draw from the median cubital vein to develop platelet-rich fibrin (PRF) and buffy coat platelet-rich plasma (BC-PRP). BC-PRP and PRF were produced with a single-spin centrifuge at 3,100 rpm for 12 minutes and processed. Local anesthesia—one carpule 3% Polocaine (54 mg) without epinephrine and one carpule 2% Lidocaine (36 mg) with epinephrine (Benco Dental)—was administrated in an infiltration manner. A full mucoperiosteal flap was raised after a midcrestal and intrasulcular incision design was made with a 15C Bard Parker blade (Figure 4). Vertical releasing incisions were made, including in the dental papilla one tooth mesial and distal to the surgical site. Collagen and elastin fibers were released and separated utilizing the dull side of a 15C blade in a back-action sweeping technique.

Figure 4. Full mucoperiosteal flap.

The recipient site was prepped with a 700 XL bur in an attempt to create a positive seat for the block graft. Perforations utilizing a No. 4 round bur on the alveolar ridge to promote bleeding points were made. A 10- × 10- × 5-mm corticocancellous allogenic block graft (Rocky Mountain Tissue Bank) was secured by placing a 1.5- × 10-mm machined TriStar Bone Graft Fixation System (IMPLADENT LTD) through the graft and into the palatal bone (Figure 5). After fixation was confirmed, the bony edges were rounded with a No. 6 round bur.

Figure 5. Allogenic block with fixation screw.

Figure 6. Collagen membrane.

Figure 7. Particulate allographic (particulate mineralized irradiated bone) and platelet-rich fibrin.

Particulate mineralized irradiated bone (MIRB) cancellous allograph (Fine [Rocky Mountain Tissue Bank]) was mixed with PRP and mortised into all voids existing between the block and host site. The entire graft was covered with PRF and a type 1 collagen resorbable membrane (OSSix Plus [OraPharma]) (Figures 6 and 7). A fixed transitional appliance (Essix) was placed. The flap was closed, consisting of a dual technique encompassing a horizontal mattress and interrupted 3.0 d-PTFE sutures (Figure 8). A 4-month healing period prior to implant surgery was established (Figure 9).

Figure 8. Primary closure, d-PTFE.

Figure 9. Surgical site after 4 months of healing.

The implant surgery procedure was prepared concerning PRP/PRF and local anesthesia exactly in the same manner as for the block graft. A midcrestal incision was made with a 15C Bard Parker blade extending distal to the maxillary right canine and mesial to the right maxillary central incisor. A full mucoperiosteal flap was reflected to expose the block retention screws and removed with the appropriate driver (Figures 10 and 11). The implant osteotomy was developed utilizing osseodensification (OD) Densah drills (Versah). The sequence was a 1.6-mm pilot drill rotating clockwise (forward), followed by 2.0-, 2.5-, and 2.8-mm Densah drills rotating in a counterclockwise (reverse) OD mode to a depth of 13 mm. A 3.2- × 13-mm SBM Legacy2 (Implant Direct) implant was inserted utilizing a straight driver to the level of the bony crest (Figure 12). A 3.2-mm transfer pin was placed, and a radiograph was taken prior to taking an impression with a heavy-body polyvinyl siloxane (Imprint III [3M]) material (Figures 13 and 14). A maxillary-mandibular relation and a shade B2/B1 were taken. A 3.2- × 2-mm healing collar was placed with a 1.25-mm hex tool and covered with a PRF bioactive membrane. The flap was approximated in a dual-closure approach with a horizontal mattress and interrupted 4.0 Vicryl sutures.

Figure 10. Full mucoperiosteal flap and allogenic block after 4 months of healing.

Figure 11. Fixation screw.

Figure 12. A 3.2- × 13-mm SBM Legacy2 implant (Implant Direct).

Figure 13. Impression transfer pin.

Figure 14. Periapical radiograph of the 2-mm healing collar.

Figure 15. Healing collar after 4 months of healing.

The restorative stage was initiated 4 months post-implant fixture placement (Figure 15). After infiltration anesthesia, the 2-mm healing collar was removed with a 1.25-mm hex tool to expose the fixture (Figure 16). A titanium abutment was placed, a periapical radiograph was taken, and an abutment screw was torqued at 30 N/cm twice over a 5-minute time interval (Figures 17 and 18). The final porcelain-fused-to-metal crown was permanently cemented with zinc oxide phosphate cement (Figures 19 and 20).

Figure 16. The fixture at 4 months.

Figure 17. Titanium abutment.

Figure 18. Periapical radiograph of the abutment/implant.

Figure 19. Final prosthesis, a porcelain-fused-to-metal crown (lateral view).

Figure 20. The porcelain-fused-to-metal crown (facial view).

DISCUSSION

Implant dentistry has provided many individuals with the opportunity to reconstruct lost oral structures.¹ The need to reconstruct a deficiency in hard and soft tissue prior to the placement of dental implants is a common prerequisite.¹¹ Many treatment approaches have been described in the literature, such as ridge expansion, GBR, and autogenous and allographic block grafts.¹² The selection of a specific technique is based on the volume of alveolar ridge reconstruction needed or whether a staged or simultaneous implant placement can be achieved.

The utilization of block grafting for the reconstruction of a horizontal ridge deficiency has demonstrated high success rates.^13,14 Autogenous block grafting is considered the gold standard because all bone development processes are involved in regeneration.¹⁵ Autogenous block grafts can be harvested from intraoral sites, such as the symphysis, ramus, or maxillary tuberosity.¹⁶ Extraoral sites utilized for grafting are the iliac crest, calvarian, and tibia. Autogenous grafts exhibit a high incidence of morbidity, paresthesia, devitalization of teeth, hospitalization, and costs.

Allogenic block grafts have become widely used in implant dentistry due to reduced morbidity and advances in processing for sterilization.¹⁷ Allogenic block grafts meet the pass criteria for bone regeneration development described by Wang and Boyapati.¹⁸ The cortical-cancellous nature of the block creates physical space, including porosity to foster vascularity to develop within the graft. The block can be fixated to the host site to create stability needed for bone growth. Allogenic block grafts have demonstrated high success rates histologically by the amount of vital bone growth they’ve enhanced.¹⁹ Furthermore, high implant survival rates are exhibited when implants are placed in allogenic block grafts.

This case report utilized a cortical-cancellous block graft sterilized via gamma radiation at 2.5 to 3.8 mrad to kill bacteria, viruses, and cells, and it was provided in a hydrated form. The hydrated form and cancellous component allow for compression with less breakage during the fixation process. The block graft is procured from the vertebra column exhibiting a curved anatomical shape.^12,20

The techniques of the block graft procedure depend highly on the execution of the flap and block protocols.²¹ A tension-free closure is needed, requiring vertical releasing incisions and release of the periosteum. Release of collagen from the periosteum and elastin fibers in the mucosa is required to coronally advance the flap for a tension-free closure. The allogenic block is placed in a surgically developed area to enhance a positive seat in the host bone. The host bone is decorticated with multiple perforations to release growth factors via the regional acceleratory phenomenon.²²

A Ti-machined fixation screw is placed through the block and into the host bone to eliminate any movement of the block graft. It is paramount that the block graft is in close approximation with the recipient site. The voids that exist around the block are filled in with particulate MIRB allograph and PRP.^23,24 PRF bioactive and collagen type 1 membranes are utilized to cover the allogenic block and particulate graft. The membranes serve to promote soft- and hard-tissue healing as well as prevent epithelial migration into the allogenic block graft sites.^25,26 

The resorption of allogenic and autogenous block grafts has been under discussion for several years. Systematic reviews demonstrate minimal resorption of both types of grafts after 12 months and that they remain stable for 5 years.²⁷ More importantly, implant survival rates in block grafts have been higher than 95%.²⁸ Further studies have exhibited the presence of new bone formation histologically after 4 months, with a diminished residual graft bone. These studies are confirmed by the presence of osteogenic markers such as bone morphogenic protein (BMP), osteocalcin, and alkaline phosphate.²⁹

Patient evaluation prior to block grafting is critical in developing a proper diagnosis. A diagnosis will guide the clinician in decision making concerning which horizontal ridge augmentation technique will accomplish a favorable outcome. A prophylaxis of adjacent teeth and an evaluation of the amount of keratinized tissue should be performed. A CBCT scan is ideal for evaluating the buccal palatal volume and shape of the ridge.³⁰ The 3D image is helpful in determining the amount of bone regeneration needed to place an implant in the ideal position. Most importantly, it assists the clinician in making the proper decision on the surgical approach. The patient was prescribed a Cephalosporin (Keflex) antibiotic, ibuprophen, and chlorhexidine prior to surgery. The patient in this report was taking the medication Escitapram (Lexapro). Individuals prescribed selective serotonin reuptake inhibitors have exhibited a higher risk for implant failure. A study has demonstrated twice the failure rate for individuals taking the medication vs non-users. The clinical failure is evident at second-stage surgery or at the restorative stage, suggesting a negative biological remodeling effect.³¹

Platelet concentrates and allographic bone serve as a synergistic combination for bone growth. A single platelet contains an excess of 1,000 growth factors, including BMP, platelet-derived growth factor, insulin-derived growth factor, endovascular growth factor, and fibroblast growth factor. Growth factors enhance the recruitment and differentiation of cells associated with soft- and hard-tissue development.³² BC-PRP, utilized in this case with an allographic block and particulate bone, provides osseoinductive and osseoconductive properties for bone development. The graft utilized for this report was derived from the human vertebral column and gamma-irradiated at 2.5 to 3.8 mrad to sterilize the graft from viruses, bacteria, and cells. It was provided in a hydrated form that maintained flexibility, thereby preventing fracture during the fixation stage.

The implant surgical stage is performed after 4 months of healing. Studies have determined that approximately 45% of the graft is replaced with new vital bone after this time interval.^29,33 In this case, the fixation screw was visible but not perforated through the mucosa. Although some resorption was evident around the head of the screw, the overall volume of the block was sufficient for implant placement. The osteotomy procedure was performed utilizing an osseodensification method due to a lower degree of drill chatter. The osteotomy was not undersized but developed using a hard-bone protocol to reduce internal forces during implant placement. This approach is utilized to prevent disturbance of the allograph and host-bone interface, which could potentially dislodge the grafted bone. The restorative stage was initiated at implant surgery due to a fixture stability of greater than 35 N/cm. 

After a 4-month osseointegration period, second-stage surgery was performed with simultaneous placement of the final abutment and crown placement. Implant occlusal principles were completed prior to the patient being discharged.³⁴

ACKNOWLEDGMENTS

The author wishes to acknowledge Tatyana Lyubezhanina, DA, and LeeAnn Klots, DA, for their assistance in preparation of this article.

REFERENCES

1. Albrektsson T, Brånemark PI, Hansson HA, et al. Osseointegrated titanium implants. Requirements for ensuring a long-lasting, direct bone-to-implant anchorage in man. Acta Orthop Scand. 1981;52(2):155–70. doi:10.3109/17453678108991776 

2. Van der Weijden F, Dell’Acqua F, Slot DE. Alveolar bone dimensional changes of post-extraction sockets in humans: a systematic review. J Clin Periodontol. 2009;36(12):1048–58. doi:10.1111/j.1600-051X.2009.01482.x 

3. Leonetti JA, Koup R. Localized maxillary ridge augmentation with a block allograft for dental implant placement: case reports. Implant Dent. 2003;12(3):217–26. doi:10.1097/01.id.0000078233.89631.f8 

4. Starch-Jensen T, Deluiz D, Tinoco EMB. Horizontal alveolar ridge augmentation with allogeneic bone block graft compared with autogenous bone block graft: a systematic review. J Oral Maxillofac Res. 2020;11(1):e1. doi:10.5037/jomr.2020.11101 

5. Elgali I, Omar O, Dahlin C, et al. Guided bone regeneration: Materials and biological mechanisms revisited. Eur J Oral Sci. 2017;125(5):315–37. doi:10.1111/eos.12364 

6. Sakkas A, Wilde F, Heufelder M, et al. Autogenous bone grafts in oral implantology-is it still a “gold standard”? A consecutive review of 279 patients with 456 clinical procedures. Int J Implant Dent. 2017;3(1):23. doi:10.1186/s40729-017-0084-4 

7. Lampert RC, Braidy HF, Zweig BE, et al. Intraoral augmentation vs allogenic block graft to preparation for dental implants placement: A retrospective cohort study. J Oral Maxillofac Surg. 2015;73:E30–1. doi:10.1016/j.joms.2015.06.050

8. Peleg M, Sawatari Y, Marx RN, et al. Use of corticocancellous allogeneic bone blocks for augmentation of alveolar bone defects. Int J Oral Maxillofac Implants. 2010;25(1):153–62. 

9. Motamedian SR, Khojaste M, Khojasteh A. Success rate of implants placed in autogenous bone blocks versus allogenic bone blocks: A systematic literature review. Ann Maxillofac Surg. 2016;6(1):78-90. doi:10.4103/2231-0746.186143 

10. Petrungaro PS, Amar S. Localized ridge augmentation with allogenic block grafts prior to implant placement: case reports and histologic evaluations. Implant Dent. 2005;14(2):139–48. doi:10.1097/01.id.0000163805.98577.ab 

11. Tolstunov L. Classification of the alveolar ridge width: implant-driven treatment considerations for the horizontally deficient alveolar ridges. J Oral Implantol. 2014;40 Spec No:365–70. doi:10.1563/aaid-joi-D-14-00023 

12. Troeltzsch M, Troeltzsch M, Kauffmann P, et al. Clinical efficacy of grafting materials in alveolar ridge augmentation: A systematic review. J Craniomaxillofac Surg. 2016;44(10):1618–29. doi:10.1016/j.jcms.2016.07.028 

13. Fretwurst T, Nack C, Al-Ghrairi M, et al. Long-term retrospective evaluation of the peri-implant bone level in onlay grafted patients with iliac bone from the anterior superior iliac crest. J Craniomaxillofac Surg. 2015;43(6):956–60. doi:10.1016/j.jcms.2015.03.037 

14. Keller EE, Tolman DE, Eckert S. Surgical-prosthodontic reconstruction of advanced maxillary bone compromise with autogenous onlay block bone grafts and osseointegrated endosseous implants: a 12-year study of 32 consecutive patients. Int J Oral Maxillofac Implants. 1999;14(2):197-209. 

15. Nkenke E, Neukam FW. Autogenous bone harvesting and grafting in advanced jaw re5sorption: morbidity, resorption and implant survival. Eur J Oral Implantol. 2014;7 Suppl 2:S203-17.  

16. Misch CM. Comparison of intraoral donor sites for onlay grafting prior to implant placement. Int J Oral Maxillofac Implants. 1997;12(6):767–76.  

17. Fuglsig JMCES, Thorn JJ, Ingerslev J, et al. Long term follow-up of titanium implants installed in block-grafted areas: A systematic review. Clin Implant Dent Relat Res. 2018;20(6):1036–46. doi:10.1111/cid.12678 

18. Wang HL, Boyapati L. “PASS” principles for predictable bone regeneration. Implant Dent. 2006;15(1):8-17. doi:10.1097/01.id.0000204762.39826.0f 

19. Waasdorp J, Reynolds MA. Allogeneic bone onlay grafts for alveolar ridge augmentation: a systematic review. Int J Oral Maxillofac Implants. 2010;25(3):525–31. 

20. Tatum OH Jr. Osseous grafts in intra-oral sites. J Oral Implantol. 1996;22(1):51–2. 

21. Kleinheinz J, Büchter A, Kruse-Lösler B, et al. Incision design in implant dentistry based on vascularization of the mucosa. Clin Oral Implants Res. 2005;16(5):518–23. doi:10.1111/j.1600-0501.2005.01158.x 

22. Frost HM. The regional acceleratory phenomenon: a review. Henry Ford Hosp Med J. 1983;31(1):3-9. 

23. Rutkowski JL, Thomas JM, Bering CL, et al. Analysis of a rapid, simple, and inexpensive technique used to obtain platelet-rich plasma for use in clinical practice. J Oral Implantol. 2008;34(1):25-33. doi:10.1563/1548-1336(2008)34[25:AAOARS]2.0.CO;2

24. Soni R, Priya A, Agrawal R, et al. Evaluation of efficacy of platelet-rich fibrin membrane and bone graft in coverage of immediate dental implant in esthetic zone: An in vivo study. Natl J Maxillofac Surg. 2020;11(1):67-75. doi:10.4103/njms.NJMS_26_19 

25. Omar O, Elgali I, Dahlin C, et al. Barrier membranes: More than the barrier effect? J Clin Periodontol. 2019;46 Suppl 21(Suppl Suppl 21):103–23. doi:10.1111/jcpe.13068 

26. Machtei EE. The effect of membrane exposure on the outcome of regenerative procedures in humans: a meta-analysis. J Periodontol. 2001;72(4):512–6. doi:10.1902/jop.2001.72.4.512 

27. Novell J, Novell-Costa F, Ivorra C, et al. Five-year results of implants inserted into freeze-dried block allografts. Implant Dent. 2012;21(2):129–35. doi:10.1097/ID.0b013e31824bf99f 

28. Schlee M, Rothamel D. Ridge augmentation using customized allogenic bone blocks: Proof of concept and histological findings. Implant Dent. 2013;22(3):212–8. doi:10.1097/ID.0b013e3182885fa1 

29. Correa LR, Spin-Neto R, Stavropoulos A, et al. Planning of dental implant size with digital panoramic radiographs, CBCT-generated panoramic images, and CBCT cross-sectional images. Clin Oral Implants Res. 2014;25(6):690–5. doi:10.1111/clr.12126 

30. Wu X, Al-Abedalla K, Rastikerdar E, et al. Selective serotonin reuptake inhibitors and the risk of osseointegrated implant failure: a cohort study. J Dent Res. 2014;93(11):1054–61. doi:10.1177/0022034514549378 

31. Bölükbaşı N, Yeniyol S, Tekkesin MS, et al. The use of platelet-rich fibrin in combination with biphasic calcium phosphate in the treatment of bone defects: a histologic and histomorphometric study. Curr Ther Res Clin Exp. 2013;75:15-21. doi:10.1016/j.curtheres.2013.05.002 

32. Schlee M, Rothamel D. Ridge augmentation using customized allogenic bone blocks: proof of concept and histological findings. Implant Dent. 2013;22(3):212–8. doi:10.1097/ID.0b013e3182885fa1 

33. Jun CM, Yun JH. Three-dimensional bone regeneration of alveolar ridge defects using corticocancellous allogeneic block grafts: Histologic and immunohistochemical analysis. Int J Periodontics Restorative Dent. 2016;36(1):75-81. doi:10.11607/prd.1950

34. Misch CE. Chapter 31: Occlusal considerations for implant-supported prosthesis. In: Misch CE, ed. Contemporary Implant Dentistry. 2nd ed. Mosby;1993:705–33.

ABOUT THE AUTHOR

Dr. Jackson graduated from Utica University with a BS degree in biology, cum laude. He received his DDS degree at the State University of New York at Buffalo School of Dental Medicine. He completed postgraduate training at St. Luke’s Memorial Hospital Center’s General Practice Residency Program. He completed his formal implant training through the New York AAID MaxiCourse in oral implantology at the New York University College of Dentistry. He is board-certified and a Diplomate of the American Board of Oral Implantology/Implant Dentistry and an Honored Fellow of the American Academy of Implant Dentistry (AAID). Dr. Jackson is the past president of the AAID. He is attending staff dentist for Faxton St. Luke’s Healthcare General Practice Residency Program. He is a member of the ADA and director of the AAID Boston MaxiCourse in oral implantology and the East Coast Implant Institute. Dr. Jackson has published several articles in peer-reviewed journals on the topic of oral implantology and implant dentistry. He can be reached via email at bjjddsimplant@aol.com.

Disclosure: Dr. Jackson is a speaker for Implant Direct but did not receive compensation for this article. 

Implant placement in an edentulous posterior maxillary site faces challenges related to the resorption of the crestal ridge and enlargement of the maxillary sinus. Both of these events are normal occurrences following the loss of the premolar or molar in the posterior maxilla. The result is insufficient crestal height to accommodate implant placement.

In 1994, Summers^1,2 was the first to publish on the use of osteotomes utilizing a crestal approach to elevate the maxillary sinus membrane and place osseous graft material to increase the crestal height to allow implant placement in the deficient posterior maxilla. Prior to this innovation, a lateral approach was utilized to elevate the sinus in preparation for implant placement. Dr. Hilt Tatum had developed the lateral window sinus approach in the 1970s, but the technique was not published until 1980.^3,4

The lateral approach is more complicated surgically, has more postoperative issues during initial healing, and has more potential problems than the crestal approach. Lateral sinus elevation is still indicated when the crestal bone is less than 3 mm, and multiple implants will be placed in the quadrant, requiring a larger area to be elevated, whereas the crestal approach is well-suited when the current crestal height is 3 mm or greater and either a single or 2 adjacent implants are planned. When the current crestal height is 4 mm or greater, sufficient elevation and grafting may be performed in conjunction with simultaneous implant placement, as stability of the implant is possible, and allowed to heal before the restorative phase is initiated. Should the existing crestal height be between 3 and 5 mm, crestal augmentation may be performed, and delayed implant placement can be performed. Following initial healing of the sinus augmentation, at the subsequent surgery, additional crestal elevation can be performed, and implants can be placed.

Contraindications to the crestal approach include, as mentioned, a crestal height of less than 3 mm and a ridge width of 3 mm or less than the planned implant width. When those factors are present, a lateral approach should be utilized.

A CRESTAL SINUS ELEVATION PROCEDURE 

Depth stop drills improve accuracy and, in combination with non-cutting drill tips, aid in preventing the tearing of the sinus membrane during the elevation process.

The drills are designed so that autogenous bone particles are pushed up through the opening in the sinus floor beneath the membrane as each progressive (larger diameter) drill is used. The drill removes bone from the inner wall of the osteotomy with a counterclockwise rotation. (Drill sets are available for both clockwise or counter-clockwise rotation.) This pushes the bone apically to elevate the membrane. The use of a sinus elevation probe after each drill in the 1.5- to 2.2-mm gold series depth is done to feel/check for a perforation through the bone at the sinus floor. The drills should not penetrate the floor of the sinus by more than 1 mm, leaving the membrane intact.

The Guide Right Sinus Elevation kit (DePlaque) contains all the components, drills, and tools to perform the crestal sinus elevation procedure (Figure 1). The Guide Right drills are available in 5 series of diameters with a 2° taper in lengths of 4, 5, 6, 7, 8, 9, and 10 mm (Figure 2). Each drill is run at 600 to 800 rpm in the surgical handpiece. The drills may be used with a guided approach or freehand, depending on the surgeon’s preference.

Figure 1. The Guide Right Sinus Elevation kit and its components (DePlaque), available for both clockwise and counter-clockwise rotation.

Figure 2. Drill series for crestal sinus elevation with 2° tapered depth stops utilized.

CRESTAL SINUS ELEVATION PROTOCOL

When using a guided approach or a flapless protocol, the crestal sinus elevation drill sequence is followed (Figure 3, steps 1, 2, and 3). Subsequent gold drills that are 4 and 6 mm long are used to depth until the bone is penetrated and the membrane is felt. After the use of each 4- to 6-mm-length gold drill, the site is evaluated with a sinus elevation probe to tacitly feel if the membrane has been contacted. The probe should be used gently to avoid perforation of the sinus membrane. If the membrane can be felt, longer drills are not utilized, and further site preparation is done with the wider Guide Right Sinus drills of the same length. For illustration purposes, we will assume that the depth before membrane contact is 6 mm.

Figure 3. Steps 1 to 3: initial steps to determine the level of the sinus membrane and thickness of the crestal bone.

To verify an intact sinus membrane, it can be checked using the Valsalva Maneuver. This maneuver involves pinching the patient’s nose and having the person try to blow his or her nose while you watch to see if any bubbles escape from the osteotomy site. If no bubbles or blood escape, the membrane has most likely not been perforated. This should be checked prior to any graft material being placed into the osteotomy. After testing with the Valsalva Maneuver, if the membrane has been perforated, select a drill 1 mm shorter than the working length that is wider than the prior drill. Use those larger diameter drills, 1 mm shorter in length, until you reach the final diameter needed.

A Rose series drill (2 to 2.9 mm) in 6 mm length is used until the drill stop contacts the crest, which pushes the autogenous bone particulate to further elevate the sinus membrane.

Cut an OsteoGen Plug (OPS625-10 Slim [IMPLADENT LTD]) into small pieces that are 3 to 4 mm long. Using the Concave Plugger (small end), compress all pieces, one piece at a time, into the osteotomy. Check again for sinus membrane perforation with the Valsalva Maneuver. Continue to increase the sinus elevation with more of the collagen or bone product until you have reached the desired implant length. Check the site with a periapical radiograph prior to placing the implant to verify the graft is confined in the area and not dispersed throughout the sinus.

Subsequent drills increasing in diameter, from Blue series (2.7 to 3.2 mm) to the Silver series (3 to 3.9 mm) in 6 mm length, are utilized to push additional autogenous particulate, widening the diameter of the osteotomy to elevate the sinus membrane (Figure 4, step 4).

Figure 4. Steps 4 to 6 utilized to push additional autogenous bone particulate into the sinus.

The final diameter of the Guide Right Sinus Elevation drills should be narrower than the planned implant’s diameter so that the implant, upon placement, engages the osseous walls crestally, providing initial implant stability (Figure 4, steps 5 and 6).

When the planned implant is a greater diameter than 4.7 mm, the Black series drills are used, which have a diameter of 3.7 mm at the tip and 4.7 mm at the drill stop. This drill is then used after filling the osteotomy with additional graft material, in this illustrated case to the 6-mm drill stop (Figure 5, step 7). The Concave Plugger is then used to add additional graft material and gently apply apical pressure to further lift the sinus membrane, allowing the graft material to elevate the membrane circumferentially and apically (Figure 5, step 8). The implant is then placed, achieving lateral compression with the crestal walls and achieving initial stability (Figure 5, step 9). A cover screw or healing abutment is placed, and soft tissue is sutured around to get primary closure if a flap is reflected. Due to the less dense bone of the posterior maxilla, it is not recommended to immediately load these implants but to allow the graft material to mineralize and the implant to osseointegrate for 4 to 6 months before the restorative phase is initiated.

Figure 5. Steps 7 to 9 utilized to push additional graft material with apical pressure to further elevate the sinus membrane.

DRILL TEMPERATURE AND ITS EFFECTS

A study on the effects of drill sharpness completed by Ercoli et al⁵ examined temperature increases with different drilling protocols. One of the parameters examined was the temperature of the drilling protocol. The results indicated drills were not significantly different at depths of 5 mm or 15 mm, or between 2- or 3-mm-diameter drills. The temperatures generated by the different types of drills were not significantly different. Clinically harmful temperatures were detected only at a depth of 15 mm during osteotomy preparations and coincided with a marked decrease in the rate of drill advancement with a resulting continuous drilling action. They concluded the properties significantly affect cutting efficiency and durability. Coolant availability and temperature were the predominant factors in determining bone temperatures. Continuous drilling in deep osteotomies can produce local temperatures that might be harmful to the bone.⁵ It has been shown in an in vitro study in bovine ribs that the use of a refrigerant solution at a temperature of 6°C reduces the increase of bone temperature during the preparation of implant sites compared with the physiological solution at the temperature of 23.7°C.⁶

There are benefits of cold drilling when creating osteotomies, especially when a flapless approach is being used with a surgical guide. Irrigation is unable to reach apical to the soft tissue during a flapless approach, and a surgical guide may hamper the irrigant from cooling the drills. Because flapless protocols involve serial drilling by increasing drill lengths at 1-mm intervals, the drills are pre-cooled, and irrigation is not necessary nor required. The drills can be pre-cooled by placing them in a refrigerator’s freezer for one hour prior to surgery. The sinus elevation protocol calls for serial drilling, increasing the depth by 1 mm at a time, which is hardly long enough for the drill to heat up to significantly injure the bone cells. Once the depth of the osteotomy is reached, the width of the osteotomy is increased by less than 1 mm with each increasing drill diameter, also using cooled drills. In serial drilling of 1-mm increments of bone depth (4-, 5-, 6-, 7-, 8-, 9-, and 10-mm lengths), switching to a fresh cooled drill for each step until the final depth is reached results in less trauma to the alveolar bone and less discomfort to the patient. After the appropriate depth is reached, the osteotomy width is also increased in small steps, limiting the trauma and heat produced by using pre-cooled drills to remove a very small amount of bone pushed apically.

CASE REPORTS

Case 1

A 70-year-old male patient presented with missing molars in the maxillary right posterior, desiring replacement to improve mastication. The first and second molars had been extracted several years before. A periapical radiograph was taken, and pneumatization of the sinus was noted. The crestal height was estimated at 6 mm (Figure 6). Treatment was discussed, and it was recommended to place an implant at the first molar site without implant placement at the second molar site. The patient was advised sinus elevation would be required for implant placement, and treatment recommendations were accepted.

Figure 6. Periapical radiograph demonstrating an estimated crestal height at site 3 of 6 mm.

An impression was taken, and a study model was made to fabricate a diagnostic guide utilizing Guide Right sleeves to be utilized during the CBCT. A cone-beam radiograph was taken with the diagnostic guide in place. The scan was imported into CS 3D Imaging planning software (Carestream Dental). A virtual implant was placed in the preferred position (Figure 7). It was determined an angle correction of 12° would be required based on the anatomy present to be incorporated into the surgical guide design (Figure 8). A corrected surgical guide was fabricated to place the planned implant in an ideal position related to the anatomy, and it was prosthetically driven.

Figure 7. CBCT views during the planning stage with Guide Right sleeves in the diagnostic stent with measurement of the crestal bone height and overlaying soft tissue available at site 3.

The patient returned, and consent forms were reviewed and signed by the patient. Following local anesthetic placement, a flapless surgical approach was utilized with the Guide Right surgical guide to follow the Guide Right sinus elevation protocol previously described. Upon creation of the osteotomy and identification of the sinus membrane, Puros (RTI Surgical) OsteoGen and 50 μg. Infuse bone graft (BMP-2) are placed into the osteotomy.

Figure 8. During virtual planning, it was determined an angle correction of 12° would be required based on the anatomy present (green line: long axis of Guide Right sleeve, blue line: long axis of the virtual implant, red line: angle correction required) to be incorporated into the surgical guide design.

Figure 9. Periapical radiograph following placement of the collagen plug strips of allograft prior to implant placement.

Figure 10. Periapical radiograph following immediate placement into the elevated sinus at site 3.

OsteoGen Plug 1020 (IMPLADENT LTD) was used to elevate the sinus membrane. The plug was sectioned into quarters lengthwise. Then 50 to 100 μg of BMP-2 in 0.40 ml sterile H₂O was applied to the plug pieces for 15 minutes prior to application. Minimal H₂O is recommended to avoid dilution of the BMP-2 once inserted into the sinus area.^7-9 Each piece of the plug is then cut into smaller pieces for the elevation of the sinus membrane. Pieces of the 50 to 100 μg of BMP-2 laced plug are introduced into the osteotomy with collage pliers and pressed apically with the plugger. The last Guide Right sinus drill was then utilized to gently move the graft apically while running counterclockwise to elevate the membrane. A periapical radiograph was then taken to verify sinus elevation and containment of the graft at the site (Figure 9). The osteotomy was widened utilizing the osteotomy final drill for the implant to be placed (Mega’Gen), and a 5- × 10-mm implant was placed (Mega’Gen). The implant length selected should not be greater than the height of the elevation. A periapical radiograph was taken to document implant placement and was within the limits of the sinus elevation (Figure 10). A 2.5-mm healing abutment was placed, the patient was dismissed, and healing would be allowed for osseointegration prior to initiation of the restorative phase.

Case 2

A 76-year-old male patient presented for implant placement at site 14 that had a missing tooth. A periapical radiograph noted 3 to 4 mm of residual crestal bone at the site. A diagnostic CBCT scan guide was created, and a CBCT scan was taken. The scan data was imported into virtual planning software, and a virtual implant was placed at the site (Figure 11).

Figure 11. CBCT views during the planning stage with Guide Right sleeves in the diagnostic stent illustrating the 3- to 4-mm crestal bone height available.

Figure 12. Periapical radiographs taken at various stages of the crestal elevation (left: following initial reverse drill osteotomy, middle: following sinus elevation, right: following implant placement).

Figure 13. CBCT views following crestal sinus elevation and implant placement illustrating the gain in crestal height to accommodate the implant at site 14.

The patient returned, and consent forms were reviewed and signed. A similar protocol as described for the prior case was followed. Following an initial reverse drill osteotomy with the Guide Right sinus elevation drills, a periapical radiograph was taken (Figure 12, left). Collagen plug pieces with BMP-2 were utilized to elevate the sinus, and a periapical radiograph was taken (Figure 12, middle). A 5- × 10-mm Mega’Gen tapered implant was placed, and a periapical radiograph was taken to document the implant and graft (Figure 12, right). A 2.5-mm healing abutment was placed, and a CBCT scan was taken documenting that the implant was encased in graft material, especially apically (Figure 13). The patient was dismissed, and healing would be allowed for osseointegration prior to initiation of the restorative phase.

Case 3

A 74-year-old female patient presented with a missing tooth 15 and tooth 16 present in a good position, requesting an implant to replace tooth 15 instead of a fixed bridge from 14 to 16. A periapical radiograph noted 3 to 4 mm of residual crestal bone at the site. Implant planning was done for maxillary left second molar that required sinus elevation. A diagnostic CBCT scan guide was created, and a CBCT scan was taken. The scan data was imported into virtual planning software, and a virtual implant was placed at the site (Figure 14).

Figure 14. CBCT views during planning stage with Guide Right sleeves in the diagnostic stent illustrating the 3- to 4-mm crestal bone height available at site 15.

Figure 15. Periapical radiograph taken following crestal sinus elevation (left) and after implant placement (right).

The patient returned, and consent forms were reviewed and signed. A similar protocol as described for the prior cases was followed. Following sinus elevation with the Guide Right sinus elevation drills, collagen plug pieces with BMP-2 were utilized to elevate the sinus, and a periapical radiograph was taken (Figure 15, left). A 5- × 10-mm Megagen tapered implant was placed, and a periapical radiograph was taken to document the implant and graft (Figure 15, right). A 2.5-mm healing abutment was placed, the patient was dismissed, and healing would be allowed for osseointegration prior to initiation of the restorative phase.

Case 4

A 69-year-old female patient presented 3 months after tooth No. 14 had been extracted for evaluation for implant placement at the site. Minimal bone was noted below the sinus after a CBCT scan was taken with a Guide Right diagnostic stent (Figure 16). Minimal crestal height was confirmed. A surgical guide was fabricated with Guide Right sleeves.

Figure 16. CBCT views during the planning stage with Guide Right sleeves in the diagnostic stent illustrating the minimal crestal bone height available.

Figure 17. CBCT after the initial reverse osteotomy pushed the crestal bone material to raise the sinus membrane.

Figure 18. CBCT following additional graft placement to further elevate the sinus membrane and implant placement.

The patient returned, and consent forms were reviewed and signed. A similar protocol as described for the prior cases was followed. Following initial elevation, a CBCT scan was taken to confirm the initial graft was contained and had not spread inside the sinus due to perforation of the membrane (Figure 17). Further graft placement and elevation were performed, and a 5- × 10-mm Mega’Gen implant was placed. A CBCT scan was taken to document the implant placement and amount of sinus elevation, confirming it was contained around the implant (Figure 18). A cover screw was placed and the patient was dismissed, and healing would be allowed for osseointegration prior to initiation of the restorative phase.

CONCLUSION

Loss of crestal height is a frequent occurrence in the posterior maxilla, complicated by periodontal bone loss that may be a causative factor for the loss of that tooth and pneumatization of the sinus. A crestal approach to increase crestal height to accommodate implant placement is a simpler, less traumatic approach than lateral sinus augmentation. The technique described using a diagnostic CBCT stent, virtual planning, and surgical guide allows a flapless approach to the procedure. Utilization of the Guide Right sinus elevation instrumentation decreases the potential for membrane perforation during elevation and osteotomy creation. This results in a simpler, more predictable approach to implant placement in the resorbed posterior maxilla.

REFERENCES

1. Summers RB. A new concept in maxillary implant surgery: the osteotome technique. Compendium. 1994.15(2):152, 154–6. 

2. Summers RB. The osteotome technique: Part 3—Less invasive methods of elevating the sinus floor. Compendium. 1994;15(6):698, 700, 702–4 passim. 

3. Boyne PJ, James RA. Grafting of the maxillary sinus floor with autogenous marrow and bone. J Oral Surg. 1980;38(8):613–6. https://pubmed.ncbi.nlm.nih.gov/6993637/   

4. Tatum H Jr. Maxillary and sinus implant reconstructions. Dent Clin North Am. 1986;30(2):207–29. 

5. Ercoli C, Funkenbusch PD, Lee HJ, et al. The influence of drill wear on cutting efficiency and heat production during osteotomy preparation for dental implants: a study of drill durability. Int J Oral Maxillofac Implants. 2004;19(3):335–49. 

6. Di Fiore A, Sivolella S, Stocco E, et al. Experimental analysis of temperature differences during implant site preparation: Continuous drilling technique versus intermittent drilling technique. J Oral Implantol. 2018;44(1):46-50. doi:10.1563/aaid-joi-D-17-00077 

7. Nevins M, Kirker-Head C, Nevins M, et al. Bone formation in the goat maxillary sinus induced by absorbable collagen sponge implants impregnated with recombinant human bone morphogenetic protein-2. Int J Periodontics Restorative Dent. 1996;16(1):8-19.    

8. Boyne PJ, Marx RE, Nevins M, et al. A feasibility study evaluating rhBMP-2/absorbable collagen sponge for maxillary sinus floor augmentation. Int J Periodontics Restorative Dent. 1997;17(1):11-25.  

9. Freitas RM, Spin-Neto R, Marcantonio Junior E, et al. Alveolar ridge and maxillary sinus augmentation using rhBMP-2: a systematic review. Clin Implant Dent Relat Res. 2015;17 Suppl 1:e192-201. doi:10.1111/cid.12156 

ABOUT THE AUTHORS

Dr. Meitner graduated from Marquette University in Milwaukee after completing a tour of duty in the US Navy, completed his certificate and board examinations in periodontics at the Eastman Institute for Oral Health at the University of Rochester in New York, and remains a part-time professor of clinical dentistry in the Department of Periodontology at the university. He has been in private practice in periodontics for more than 30 years in Pittsford, NY, and is the developer of the Guide Right protocol. He can be reached at swmeit4@gmail.com.

Dr. Kurtzman is in private general practice in Silver Spring, Md. A former assistant clinical professor at the University of Maryland, he has earned Fellowships in the AGD, the American Academy of Implant Prosthodontics, the American College of Dentists, the International Congress of Oral Implantologists (ICOI), the Pierre Fauchard Academy, and the Association of Dental Implantology; Masterships in the AGD and ICOI; and Diplomate status in the ICOI and the American Dental Implant Association. He has lectured internationally, and his articles have been published worldwide. He has been listed as one of Dentistry Today’s Leaders in Continuing Education since 2006. He can be reached via email at dr_kurtzman@maryland-implants.com.

Disclosure: Dr. Meitner is a product developer and non-paid consultant for DePlaque. Dr. Kurtzman reports no disclosures.

For anyone who has been involved with an All-on-4 procedure, the thought of going into surgery with no interim ready to convert may not only sound strange but quite scary. As prosthodontists, we have been involved in hundreds of these cases and had the teeth ready to convert hundreds of times. So why would we now intentionally begin a surgery without the teeth? Technology!

While we have had the technology and digital know-how for years to do this, we have resisted. We started immediately loading full arches when the only method available was converting a traditional denture. When stackable guides started becoming popular, we transitioned to this for the improved accuracy of implant placement and ease of conversions. With both of these methods, we had the problem of interims breaking weeks to months into the process. This would significantly impact the experience patients had and would put their implants at risk. So, when Smart Denture Conversion abutments came to market, we were early adopters. They ease conversions but also provide a prosthesis with more strength. This became our method of choice for conversions in our practice. We started using them with dentures and later began milling prosthetics supported by stackable guides. To this day, we still use stackable guides and Smart Denture Conversion abutments with great success and ease. So why try something new?

CASE REPORT

Allison presented to our dental implant center with a failing maxillary dentition. We discussed her options, and she elected to go with the All-on-4 option and replace all of her maxillary teeth with a prosthesis supported by at least 4 dental implants. Typically, this prosthesis ideally requires 15 mm of restorative space to make room for not only the teeth but the gingiva as well. Through our implant planning, it was found that if we wanted 15 mm of restorative space, we would not have enough bone for the implants. Allison had a short maxilla, so we changed the plan. We transitioned to a full-arch, implant-supported bridge—what Misch called an FP1 prosthesis. This prosthesis is just bridges replacing the teeth, with no gingiva. So, what was the challenge?

We have enjoyed years and years of not having patients return with their interim prosthetics broken while waiting for their implants to integrate. We feel much of our success was from drawing a line and not crossing it. Making an immediate load conversion of an FP1-type prosthesis comes with concern—we can’t make a thicker interim prosthesis since the prosthesis itself is replacing just the teeth. So what do we do?

We have had the software and 3D printers for years, capable of designing teeth and printing them all on the day of surgery. When doing this, we can design the interim to sit directly on the multi-unit abutments and be held in place with Rosen screws (Rosen Screws). This combination provides the added strength in a thinner prosthesis but isn’t possible without technology. I would like to walk you through the day of surgery.

Before Surgery

Regardless of the route we choose for getting our patients into their interim prostheses, it always begins with a records appointment. We discuss with patients their goals for their new smiles. Once we know where we are going, we evaluate where we are at now (midline, incisal edge position, vertical, occlusal plane, etc). We also take photos, intraoral scans (TRIOS [3Shape]) (Figure 1), and CBCT scans (OP 3D [DEXIS]).

Figure 1. Preoperative intraoral scan.

From everything we gathered at Allison’s first visit, we designed her teeth digitally with exocad (exocad America) (Figure 2). We referenced the list of changes and photos to ensure the design achieved her goals. Something to note here is that while we had designed the new teeth, we still had the old teeth aligned to them (transparent in the image)—this is important later.

Figure 2. Teeth designed in exocad (exocad America).

After the teeth are decided, they are brought into the implant planning software (Blue Sky Plan [BlueSkyBio]). When placing implants for an FP1 prosthesis, it is critical to position them directly beneath the teeth they are replacing. The last thing you want is an implant going into an embrasure space where a papilla is supposed to be. While it is possible to place a full-arch prosthesis directly to implants, it is very difficult. It is the reason multi-unit abutments were created. So, for Allison’s plan, the implants and abutments were planned below the planned teeth at Nos. 3, 5, 7, 10, 12, and 14 (Figure 3). After the implants and abutments were confirmed, this was exported out, finalized as a final prosthesis design (Figure 4), and later used in the guide fabrication (Figure 5).

Figure 3. Implants placed in Blue Sky Plan (BlueSkyBio) directly below the teeth.

Figure 4. The prosthestic design adapted to the planned implants.

Figure 5. The planned prosthetic was incorporated into the surgical guides.

All of the planning we completed was brought into 3D editing software (Meshmixer [Autodesk]) and used to fabricate the surgical guides used at the surgery. Allison’s guides started with a tooth-supported guide attached to a foundation guide. This foundation guide stayed attached to her maxilla for the duration of surgery, serving as a stable base for a variety of other guides.

To summarize the presurgical planning goals, we then had a variety of surgical guides designed and fabricated, as well as the interim prosthesis designed but not fabricated (milled or printed).

Surgery

After Allison was sedated, our surgery started. After administering local anesthetic to her maxilla, a facial flap was laid from left to right. When using a foundation guide with stackable pieces, this flap needs to be extended further apically than usual. The foundation guide starts attached with plastic pins to a tooth-supported guide. This allows us to use a stable starting point as a reference to ensure we’ve accurately transferred the digital plan to surgery. With the one guide securely fitted to the teeth, we secured the foundation guide to her bone.

Note that with this technique, we made Allison’s foundation guide in titanium (Titanium 98 mm Disc [Imagine USA]). As you will see, we needed the guide to stay exactly where we put it for the duration of the procedure. Our lab (Renew Full Arch Lab) designed a millable foundation guide just for this technique. We wanted something more stable than 3D printed resin guides. We sandblasted the titanium so that it scanned easier. Also note that, with her case, we opted to use screws (Pro-Fix [Osteogenics]) rather than pins to secure the guide. Again, this was for improved stability. The third design element to ensure stability was to have the guide touch the bone in those few places where the screws go in. We have pinned a lot of floating resin guides for All-on-4 surgeries and can assure you that these 3 changes make a significant difference in stability.

When the screws were in, the plastic pins were removed, and the tooth guide was taken out (Figure 6). The next step was important to this particular technique—making a scan of the patient’s teeth and the foundation guide (Figure 7). This was the first of 2 scans used to design her interim prosthesis.

Figure 6. After the foundation guide was screwed to the bone, the tooth guide was removed.

Figure 7. The teeth and foundation guide were scanned with TRIOS (3Shape).

Then it was time to extract the teeth. With an FP1 procedure, you aren’t removing the bone to make room for an All-on-4 prosthesis. Instead, you are trying to maintain as much bone as possible since only bone can support the gingiva you hope will form the papillae (Figure 8). But we needed to remove any bone that would prevent the future teeth from seating. To guide this very specific alveoplasty, we took the same design of the arch and added it to the stackable guide. This gave us a clear view of the bone that needed to be removed (Figure 9). The goal was to remove enough bone to make room for gingiva (1.5 to 2.0 mm).

Figure 8. Teeth were extracted with an effort to preserve as much bone as possible.

Figure 9. The designed prosthesis was printed and rested on the foundation guide.

Figure 10. The implant guide was used to accurately place the implants.

Figure 11. Multiple abutments were placed on the implants.

Adequate bone was removed, and the implant guide was used to place the dental implants (GM Drive [Neodent]) according to our plan (Figure 10). Then the multi-unit abutments were placed (Figure 11), ensuring no contact with bone (note that it will likely require further alveoplasty). The abutments were then torqued to place. The next step is the second most important part of this technique. Photogrammetry requires that we scan something that acts as a fiduciary to relate its highly accurate data to the intraoral scan. With our scanner, there are cylinders for this purpose. These were placed on Allison’s multi-unit abutments and scanned (Figure 12). This scan included the foundation guide and cylinders (Figure 13). These 2 scans (teeth with guide and guide with cylinders) were immediately given to the lab for alignment.

Figure 12. The iMetric cylinders were placed on the multi-unit abutments.

Figure 13. The foundation guide and iMetric cylinders were scanned with the TRIOS.

Figure 14. The iMetric scan bodies were placed on the multi-unit abutments.

The cylinders were removed and replaced with the photogrammetry scan bodies (Figure 14). These were used with the photogrammetry unit (iCam [iMetric 4D]) to scan the implant positions. It scans all of the scan bodies in less than a minute and provides better accuracy than most desktop scanners and traditional jigs. This data was also given to the lab. It is this technology that makes this technique possible.

Photogrammetry has been around for decades in a variety of industries but is relatively new to dentistry. Intraoral scanners are very accurate when scanning small objects like teeth. But they fail when asked to scan longer distances, such as, for example, one side of an arch to the other. Desktop scanners have traditionally been used to scan for full-arch, implant-supported prosthetics, but they require a model. Getting a verified abutment-level model is best achieved through taking preliminary impressions and then final impressions with the use of a jig. Photogrammetry gets better accuracy within minutes. It’s a beautiful thing and a must for clinicians doing a lot of full-arch implant dentistry.

When the scan is complete and sent to the lab, they can finalize the design. In the meantime, one must graft around implants, graft all sockets, and suture. After the teeth are ready, they are inserted, and Rosen screws are used to secure them. Rosen screws are designed to provide a wedging effect and are meant to be hand-tightened. Once the teeth were inserted, occlusion was dialed in, and then screw access holes were filled with PVS.

Lab Work

The key to designing quickly at the time of surgery is that the design is done before surgery but is just missing the implant connections. With 2 intraoral scans and a photogrammetry scan, the rest is easy. All 3 scans are aligned, and the design is adapted to the implant positions. I’ll walk you through the details.

When the 2 intraoral scans were sent to the lab during surgery, the lab started the sequence of alignments. Remember, the design of the interim was already aligned with the preoperative scans of her failing dentition. The first scan from surgery has 2 important things: the current teeth and the foundation guide. The teeth in the first new scan are used to align this scan to the pre-op scan (Figures 15 and 16). This relates the foundation guide to the interim design. The second new scan has 2 important things as well: the foundation guide and the cylinders. This scan is aligned with the first new scan using the foundation guide as the common reference between them (Figures 17 and 18). These 2 alignments achieve a very important goal: to align the interim design to those photogrammetry cylinders (Figure 19). We can then use those cylinders to align the highly accurate photogrammetry data to the scene (Figure 20), which means the implant positions are now where we need them. The final step is adapting the interim design to the implant positions (Figure 21).

Figure 15. Common points were selected between the first surgery scan and the preoperative scan.

Figure 16. The exocad software used its alignment algorithm to match the scans (dark blue is considered a perfect alignment).

Figure 17. It’s the same idea in the sec- ond scan: The common points on the 2 guide scans are selected.

Figure 18. The dark blue denotes great alignment between the guide in scan 1 and scan 2.

Figure 19. The iMetric cylinders were aligned to the presurgery interim design.

Figure 20. The scan of the cylinders was used to align the photogrammetry data.

Figure 21. The presurgery design was adapted to the newly scanned implant positions.

The next step in the lab is to 3D print the interim design. It is important to note certain requirements of a printer used for this purpose. Not all 3D printers have adequate accuracy to print a design meant to fit a multi-unit abutment and screw. Second, it’s also important to consider the speed of the printer since the patient is waiting. And lastly, the printer has to be able to print a tooth-colored material (Rodin Sculpture [Pac-Dent]) that can withstand occlusal forces.

The final lab step was to wash the print, cure it, and finish it. Allison’s interim prosthesis was washed twice in isopropyl alcohol and cured in a flash unit surrounded by nitrogen (Otoflash G171 [anax USA]). We then used pumice and acetyl polish to give the print a nice shine. It was then ready for insertion.

CONCLUSION

As you can see, this technique is a careful dance between the clinician and the lab. Each has very specific roles and must do them to the best of their ability to ensure success. We have the luxury in our practice to share a roof with the lab so that we can keep everything in-house. For our lab’s clients, we design the interim prostheses before surgery; they capture the scans; we align and adapt; and they print, finish, and deliver. This technique avoids traditional conversions and delivers more predictable, custom interims. This means we are more likely to hit our target goals and give our patients the smiles they are hoping for.

ABOUT THE AUTHOR

Dr. Farley is a surgical prosthodontist practicing in Mesa, Ariz. He and his business partner own and operate Revive Dental Implant Center and Renew Full Arch Lab (renewdigitaldesign.com), where they utilize the newest technologies to provide high-quality full-arch prosthetics. Dr. Farley also teaches live and online courses through their education center, DigitalDDS (digitaldds.com). He can be reached at nfarley@revivedental.com.  

Disclosure: Dr. Farley reports no disclosures. 

In the early 2000s, the field of dentistry was shocked when published reports of severe complications and morbidity surfaced with patients on a newer therapeutic antiresorptive medication (bisphosphonates). Marx¹ and Ruggiero et al² were the first to report patients taking bisphosphonates for cancer treatment (IV) or osteoporosis (oral) becoming susceptible to bone necrosis lesions termed medication-related osteonecrosis of the jaw (MRONJ). Since that time, there has been significant debate and controversy with no general consensus on how bisphosphonate patients should be treated (eg, no treatment, no drug modification, drug holiday, C-Telopeptide [CTX] Test) for dental procedures in implant dentistry.  

Currently, the field of implant dentistry is entering a new challenge, which could be far more significant and controversial than bisphosphonates. A relatively newer class of therapeutic drugs (“biologics”) has been introduced in the medical world for the treatment of a wide spectrum of diseases, including autoimmune, inflammatory, dermatologic, and infectious diseases and neoplasms. These novel medications utilize living organisms and recombinant DNA in their manufacturing processes. Unlike conventional medications that target the entire immune system (eg, steroids, methotrexate, and cyclosporine), biological therapeutics are significantly more beneficial as they only target particular portions of the immune system. This most commonly will result in fewer side effects for the patient.³

Biological therapeutics are the fastest-growing sector in the pharmaceutical industry, with total revenues exceeding $163 billion annually. The annual growth rate is staggering at 8%, far greater than conventional pharmaceuticals, which approximate 4%. Since 1995, the applications for biologic therapeutic patents have increased by more than 25% per year. There are currently more than 200 approved biologic drugs on the market, with approximately 1,500 drugs being evaluated in clinical trials and many more drugs in the pipeline.⁴ The ability of these drugs to treat previously untreatable diseases is what is fueling this growth. With the unlimited scope and potential of these medications, more targeted, effective, and personalized biologic medications will be developed in the future to treat even the most complex diseases.⁵

BIOLOGIC MEDICATIONS

Biologic medications have been approved for a wide array of conditions and disease processes. Biologics are most commonly classified by their suffixes as to their origin: human (“mab”), humanized  (“zumab”), or chimeric (“ximab”). Table 1 describes the most common biologics and their intended targeted conditions and diseases.

Possible Side Effect Complications in Dentistry

Although biologic drugs have far fewer side effects than conventional pharmaceuticals, they do specifically have potential adverse effects on normal bone physiology. There exist many case reports in the medical literature concerning postoperative infections involving biologic medications, especially following orthopedic surgery. Giles et al⁶ showed a significant increase in post-op infections after orthopedic surgery procedures. Ruyssen-Witrand et al⁷ also reported an increased infection rate in rheumatoid arthritis patients undergoing orthopedic joint surgery.

In the dental literature, most documentation is via case reports, as little research or data exists on how biologic medications may affect patients undergoing invasive dental procedures (eg, extractions, dental implants, and bone grafts). Ciantar and Adlam⁸ reported a case of mandibular osteomyelitis on a patient being treated with Infliximab for juvenile arthritis. Sri et al⁹ reported one of the first cases involving an extraction and the development of a mandibular osteomyelitis in a patient being treated for psoriasis with biologic medications (Figure 1).

Figure 1. (a) Preoperative image prior to extraction of mandibular teeth.

Figure 1. (b) Post-extraction osteomyelitis resulting from the patient being treated with Etanercept.

Tsuchiya et al¹⁰ related a case of suppurative osteomyelitis derived from periapical periodontitis in a patient being treated for Crohn’s disease. Ziobrowska-Bech et al¹¹ presented a 10-year study showing a relationship between biologic drugs and children with chronic noninfectious osteomyelitis with either mono- or multifocal bone lesions.

Cillo and Barbosa¹² reported on the first documented implant-related complication with a biologic medication. An adalimumab-related dental implant surgical-site infection presented in a patient 2 weeks after extractions and immediate placement of 5 mandibular implants (Figure 2).

Figure 2. (a) Patient presented with draining mandibular exudate to Allegheny General Hospital (Pittsburgh) emergency department 2 weeks after extraction and placement of 5 mandibular implants.

Figure 2. (b)

Figure 2. (b and c) Extraoral image and CT scan depicting significant fluid collection inferior and posterior to the mandibular symphysis with extension of submental abscess into the bilateral submandibular spaces.

Figure 2. (d) Extraoral drainage with implant removal was completed. (Courtesy of Joseph E. Cillo Jr., DMD, MPH, PhD.)

After extraoral incision and drainage of the involved fascial spaces, implant explantation and debridement of necrotic mandibular bone were completed. The patient healed uneventfully after treatment. Therefore, it appears a definite association exists between biologic medications and post-op infections after invasive dental surgery; however, without controlled, prospective cohort studies, a true prevalence and relationship cannot be established.

POSSIBLE PHARMACOLOGIC RELATIONSHIP

So how does this newest classification of medications result in post-op dental complications? Specifically, biologic medications are tumor necrosis factor (TNF) inhibiting drugs that utilize the immune system’s natural processes to detect and destroy abnormal cells.¹³ TNF plays a central role in the body’s ability to fight infection. When this factor is inhibited (as with biologic medications), an increased susceptibility to infection may result. Multiple studies have shown a direct association between TNF inhibitors and interference with normal bone physiology. Biologic medications have been reported in the literature to decrease bone turnover,^14-16 have direct effects on the viability of osteocytes,¹⁷ and inhibit osteoclastgenesis.¹⁸ Therefore, these detrimental effects on the bone-healing process closely parallel the genesis of MRONJ with antiresorptive (bisphosphonate) medications.  

PREOPERATIVE PREVENTIVE MEASURES FOR BIOLOGIC MEDICATION PATIENTS 

With the number of dental implant procedures increasing significantly every year, clinicians must be aware of the possible sequelae of patients taking biologic medications and undergoing invasive dental procedures. Due to the increased risk of post-op infection, clinicians must work closely with the patient’s physician in the development of a treatment plan that is case-specific for the reduction of post-treatment complications. Medical consultation and clearance are highly recommended prior to any proposed implant treatment, especially on patients taking biologic medications.¹⁸

If a patient presents with a past history of biologic medication use but is not currently being treated with the medications, medical consultation is still recommended to ascertain the level of immune suppression and current status of the patient’s disease process. A detailed verbal and written informed consent is suggested. 

For patients currently taking biologic medications and who have future invasive surgical procedures planned, medical consultation/clearance is highly recommended. There exist many factors the physician will take into consideration in the determination of the best course of treatment for the patient. In general, this should include the specific medication in question (ie, medication toxicity and strength and the potential for adverse effects), medication dosage, treatment duration, comorbidities, the possibility of disease rebound, and type of surgical procedure to be performed. In most cases, modification of the medication is indicated in the perioperative period, which includes a discontinuation via a drug holiday. Smith et al¹⁹ recommends a drug discontinuation of approximately 4 to 5 times the half-life of the medication.

For example, possible discontinuation (drug holiday) prior to surgery for the most common biologics would include etanercept (2 weeks), adalimumab (6 to 8 weeks), and infliximab (4 to 6 weeks).²⁰ The patient’s physician should instruct the patient on the specific instructions of the drug holiday. In no situation should a dental provider modify a patient’s biologic medication that the patient’s physician prescribes. In addition, detailed verbal and written informed consent should be presented to the patient. Biologic therapy is most commonly restarted post-op when satisfactory wound healing is present with no evidence of infection (see Table 2). 

CONCLUSION

In conclusion, biologic drugs are an exciting new class of medications that have revolutionized the treatment of a wide spectrum of conditions and diseases in medicine. In the future, more and more of our dental patients will be utilizing these medications for a full array of disease processes as this promising classification of drugs will continue to grow and become more complex. Therefore, dentists must be aware of the possible complications that may arise from these medications, especially in combination with dental implant procedures.

Unfortunately, there exists minimal research that can quantify the relationship extent between post-op infections and the use of biologic medications. Caution must be used when treatment planning extractions, dental implants, and bone grafting procedures with concomitant use of biologic medications. Post-op infection is the most common adverse effect; therefore, clinicians must be prudent in evaluating the patient pre- and post-op along with consultation with the patient’s physician. In the future, a clearer picture will be determined of the association and risk between TNF-alpha inhibitor therapy and postsurgical infections as more research is completed on this topic.

REFERENCES

1. Marx RE. Pamidronate (Aredia) and zoledronate (Zometa) induced avascular necrosis of the jaws: a growing epidemic. J Oral Maxillofac Surg. 2003;61(9):1115–7. doi:10.1016/s0278-2391(03)00720-1 

2. Ruggiero SL, Mehrotra B, Rosenberg TJ, et al. Osteonecrosis of the jaws associated with the use of bisphosphonates: a review of 63 cases. J Oral Maxillofac Surg. 2004;62(5):527–34. doi:10.1016/j.joms.2004.02.004 

3. Craik DJ, Fairlie DP, Liras S, et al. The future of peptide-based drugs. Chem Biol Drug Des. 2013;81(1):136–47. doi:10.1111/cbdd.12055 

4. Otto R, Santagonisto A, Schrader U. Rapid growth in biopharma: Challenges and opportunities. In: From Science to Operations: Questions, Choices and Strategies for Success in Biopharma. McKinsey Co.; 2014. 

5. Kesik-Brodacka M. Progress in biopharmaceutical development. Biotechnol Appl Biochem. 2018;65(3):306–22. doi:10.1002/bab.1617

6. Giles JT, Bartlett SJ, Gelber AC, et al. Tumor necrosis factor inhibitor therapy and risk of serious postoperative orthopedic infection in rheumatoid arthritis. Arthritis Rheum. 2006;55(2):333–7. doi:10.1002/art.21841 

7. Ruyssen-Witrand A, Gossec L, Salliot C, et al. Complication rates of 127 surgical procedures performed in rheumatic patients receiving tumor necrosis factor alpha blockers. Clin Exp Rheumatol. 2007;25(3):430–6. 

8. Ciantar M, Adlam DM. Treatment with infliximab: Implications in oral surgery? A case report. Br J Oral Maxillofac Surg. 2007;45(6):507–10. doi:10.1016/j.bjoms.2006.06.004 

9. Sri JC, Tsai CL, Deng A, et al. Osteomyelitis occurring during infliximab treatment of severe psoriasis. J Drugs Dermatol. 2007;6(2):207–10. 

10. Tsuchiya S, Sugimoto K, Omori M, et al. Mandibular osteomyelitis implicated in infliximab and periapical periodontitis: A case report. J Oral Maxillofac Surg Med Pathol. 2016; 28(5):410–5. doi:10.1016/j.ajoms.2016.03.003

11. Ziobrowska-Bech A, Fiirgaard B, Heuck C, et al. Ten-year review of Danish children with chronic non-bacterial osteitis. Clin Exp Rheumatol. 2013;31(6):974–9. 

12. Cillo JE Jr, Barbosa N. Adalimumab-Related Dental Implant Infection. J Oral Maxillofac Surg. 2019;77(6):1165–9. doi:10.1016/j.joms.2019.01.033 

13. Mazurek J, Jahnz-Różyk K. The variety of types of adverse side-effects during treatment with biological drugs. Int Rev Allergol Clin Immunol Family Med. 2012;18:35–40.

14. Luo G, Li F, Li X, et al. TNF‑α and RANKL promote osteoclastogenesis by upregulating RANK via the NF‑κB pathway. Mol Med Rep. 2018;17(5):6605–11. doi:10.3892/mmr.2018.8698 

15. Hehlgans T, Pfeffer K. The intriguing biology of the tumour necrosis factor/tumour necrosis factor receptor superfamily: players, rules and the games. Immunology. 2005;115(1):1-20. doi:10.1111/j.1365-2567.2005.02143.x

16. Liao HJ, Tsai HF, Wu CS, et al. TRAIL inhibits RANK signaling and suppresses osteoclast activation via inhibiting lipid raft assembly and TRAF6 recruitment. Cell Death Dis. 2019;10:77. doi:10.1038/s41419-019-1353-3

17. Marahleh A, Kitaura H, Ohori F, et al. TNF-α directly enhances osteocyte RANKL expression and promotes osteoclast formation. Front Immunol. 2019;10:2925. doi:10.3389/fimmu.2019.02925 

18. Ohori F, Kitaura H, Ogawa S, et al. IL-33 inhibits TNF-α-induced osteoclastogenesis and bone resorption. Int J Mol Sci. 2020;21:1130. doi:10.3390/ijms21031130 

19. Smith CH, Anstey AV, Barker JN, et al. British Association of Dermatologists’ guidelines for biologic interventions for psoriasis 2009. Br J Dermatol. 2009;161(5):987-1019. doi:10.1111/j.1365-2133.2009.09505.x 

20. Radfar L, Ahmadabadi RE, Masood F, et al. Biological therapy and dentistry: a review paper. Oral Surg Oral Med Oral Pathol Oral Radiol. 2015;120(5):594-601. doi:10.1016/j.oooo.2015.07.032

ABOUT THE AUTHOR

Dr. Resnik received his dental degree from the University of Pittsburgh School of Dental Medicine. Upon graduation from dental school, he continued his training at the university, receiving a specialty degree in Prosthodontics, a surgical fellowship in Oral Implantology, and a Master’s degree in Oral Implantology/Radiology. He has been faculty and surgical director of the Misch Resnik Implant Institute for more than 30 years. He is also director of the Resnik Hands-On Surgical Implant Boot Camps in Ohio and the Dominican Republic.

Dr. Resnik maintains faculty positions at numerous universities, including the University of Pittsburgh (Graduate Prosthodontics), Temple University (Oral Implantology and Periodontics), and Allegheny General Hospital (Oral & Maxillofacial Surgery) in Pittsburgh.

Along with his passion for lecturing and education, Dr. Resnik is also an accomplished author, having published more than 200 articles, and his recent textbooks, Avoiding Complications in Oral Implantology and 4th Edition of Contemporary Implant Dentistry, are best sellers in the field of implant dentistry.

Dr. Resnik currently maintains a private practice in Orlando. He can be reached at resnikdmd@gmail.com.

Disclosure: Dr. Resnik reports no disclosures. 

I didn’t realize what had happened to me until I had hit rock bottom.  I just couldn’t do it anymore. I hated my practice. I regretted dentistry. I was so afraid of getting sued, getting a bad review, or disappointing someone. Nothing I did felt right. I was totally burnt out.

At that point, I only had two options available to me.  I cut my losses, leave dentistry, and work off my educational and practice debt in some other job – maybe in a cubicle situation – maybe I could go to law school so I could be the one suing. Or, I could get to the roots of my burnout, deal with the causes, and turn this mess around into something good. Gratefully, I chose the second option.   

It took years but during the long climb back to getting back to enjoying dentistry, I learned a lot about burnout, what causes it, and how to avoid it.  I recently pulled this hard-won wisdom into my book, The Stress-Free Dentist: Overcome Burnout and Start Loving Dentistry Again[1]. I don’t want any other dentist to have to go through what I did.  But if they are, then I have a few encouraging words for you because trust me I’ve been there and back.  YOU CAN DO THIS. 

You can stop burnout before it stops you, and this book is chock full of information on how to do that.  Once you’ve gotten past the stress and burnout, you can finally be engaged at work, at home, and actually, be happy with your profession.

There are many reasons why dentists get burned out.  Some of the big ones are

• The overwhelming amount of debt or overhead
• Lack of HR and business training
• The day-to-day exhausting nature of the profession

It’s important to remember to not give in to the false belief that dentistry is just a stressful profession and there is nothing you can do, or that this is the profession I chose and I’ll just have to deal with the stress until I retire. No. This is no way to live and this mentality is unsustainable for a 40-year career. 

There are concrete steps you can take to relieve pressure in these areas. For instance, one way to conquer this false belief is to invest in yourself, learn to deliver a new treatment or technology, and introduce it into your practice.  Adding these new modalities, especially high-value services such as guided Implantology (implant dentistry), 3-D printing, impression-less digital scanners, clear aligners, and/or sleep apnea and airway treatments can create what I call the three R’s: Return on investment,  Re-energize your staff, and practice, and Reinvent yourself.

5-PART SERIES

This will be the first of a five-part series focusing on how dentists can rejuvenate their careers and overcome or avoid burnout by adding some of these high-value treatments and technologies. 

For this installment, we’ll focus on adding digital planning and guided implant dentistry.

“Digital plans and fully guided surgery systems are a technology that I, my staff, and my patients love because the surgeries are quicker, more accurate, predictable, and it causes less overall stress.”

Adding implants to your practice can feel like a daunting task, especially if you have minimal or no experience with them. It doesn’t have to be that way. Especially if you are digitally planning your cases and using surgical stents and fully-guided implant surgery. If you get the proper training and onboard your staff and take things slow with proper case selection, it can be a rewarding game changer for you and your practice.

BETTER-THAN-EXPECTED STRESS RELIEF

Digital plans and fully guided surgery systems are a technology that I, my staff, and my patients love because the surgeries are quicker, more accurate, predictable, and it causes less overall stress. Less-stressed patients relieve my stress as well. Better for me, better for the staff, and of course, better for the patient.  Its win-win-win.

THE END GAME IN MIND

I have a predictable digital workflow for my implant cases. I mark any vital anatomy and merge my CBCT with the corresponding impression or scan, I virtually plan my cases in implant dentistry by starting with the crown or prosthesis first. I essentially work backwards, starting with the end restoration in mind. I then place the implant into the digital plan. From there I can customize the case. 

Sometimes I have to completely change my treatment plan.  

The important thing is that I have essentially performed the surgery and placed the restoration on my computer before I have even touched the patient. This typically creates a predictable surgery and ultimately excellent prosthetic result. It’s important to remember that the patient is not in your chair to get an implant. They are there to replace their missing tooth or teeth with an esthetically functioning crown or prosthesis. 

This backward planning will also show you if there are going to be prosthetic challenges that you and the patient need to know about. Planning backwards will help you avoid mistakes and complications, reduce stress, and create a collaborative experience with the patient. 

It may also turn out to be a case that you don’t feel comfortable working on.

 TAKE IT SLOW

As you do more cases, you will get more confident and competent, and your case numbers and acceptance rate will go up. It becomes a domino effect that the entire practice can feel. Make no mistake, though, the digital plan and guided surgery are only as good as your brain and the surgical and restorative execution of the implant. A race car doesn’t drive itself. There has to be a skilled driver with a well-planned strategy to win the race. I highly recommend you start with simple cases. 

Patient selection and case selection in the early learning phase are critical. Know your anatomy and your limitations. Don’t stray out of your comfort zone. For example, starting your journey into implant dentistry by replacing a central incisor, in close proximity to a sinus or nerve, an area deficient in bone, or by attempting an immediate placement can get you into trouble and ruin your confidence. Start with a molar or premolar with lots of bone and on an easy to work on patient. 

GREAT FOR MARKETING AND GETTING PATIENTS TO SAY YES 

There’s nothing more frustrating than when you invest in some technology or just learn a new technique and you can’t get patients to move forward with treatment. Well, during the initial implant consultation, I explained my entire digital workflow for placing and restoring implants. I will explain how I will take a CBCT of their jaw and an intra-oral scan of their teeth and merge them together in an implant planning software. 

I will then virtually place the crown for future tooth position and then place and adjust my implant. From there, I export the case and 3D print a surgical guide. The patients can sense my passion and are typically impressed with the technology that it becomes easier for them to accept and move forward with treatment. After successful and efficient treatment, they are very inclined to post on social media and tell their friends and family all about it. 

ENJOY GOING TO WORK EVERY DAY

Life is too short to dread going to work every day. For me taking things slow, not straying out of my comfort zone when adding digital planning and guided implant surgery to my practice has decreased those Sunday night blues.  Now implant dentistry is one of the least stressful, more enjoyable, and financially rewarding treatments I provide on a weekly basis.

For me, being able to control my stress levels by making choices and having a positive impact on patients has relieved my burnout. If you can feel yourself losing joy in dentistry and wishing you could change your past, there’s hope. 

Find some tools that make you happy and expand your practice and your options. Dentistry is a great life once you find your groove, but it can take a while to get there. With new treatment modalities and keeping up with the latest technology, you can start loving your job again.

ABOUT THE AUTHOR

Dr. Eric Block is a full-time practicing dentist in Acton, Massachusetts, husband, and father of two kids. He is on a mission to help dental professionals across the country overcome burnout and anxiety.

He authored his first book titled “The stress-free dentist: Overcome burnout and start loving dentistry again.”

He is the founder and CEO of the marketplace website called DealsforDentists.com, which helps dentists save time and money by helping them find new customer offers from companies across the industry.

He also interviews dentists and vendors on the Deals for Dentists Podcast and can be reached at info@dealsfordentists.com or info@thestressfreedentist.com.

Guided bone regeneration (GBR) is the most common method used for bone augmentation in implant dentistry. GBR utilizes a barrier membrane to occlude soft-tissue cells and allow slower growing bone cells to repopulate the defect and regenerate bone.¹ Additional principles for successful GBR include tension-free primary closure of the flap over the site, angiogenesis during healing to provide the necessary blood supply and undifferentiated mesenchymal cells, space creation, and maintenance for bone ingrowth, and stability of the wound during healing.² The type of membrane used for GBR is based on several factors, including the morphology of the osseous defect, rigidity for space maintenance, barrier function, and handling characteristics. Another important consideration is the type of bone graft material used under the membrane. This article will discuss characteristics of GBR membranes that direct their use for the treatment of various bone defects.

Membranes for GBR

Proper membrane selection is critical for optimal bone regeneration. There are several membranes available today, each with distinctive characteristics that should be considered to optimize clinical performance and improve outcomes. Membranes can generally be classified as either non-absorbable or absorbable. Non-absorbable membranes remain intact during healing and bone regeneration. They exhibit biocompatibility, exceptional mechanical strength, increased rigidity, and favorable space maintenance. These features make them ideal for horizontal and vertical bone augmentation, especially when managing non-space-making defects. However, this type of membrane requires a second surgical procedure for removal and is more technically challenging to use as it requires rigid fixation with tacks or screws. They also have a higher risk of exposure to the oral environment, thus increasing the risk of secondary infection and diminished bone regeneration.³ 

Figure 1. Preoperative view of 2 failing dental implants replacing the mandibular incisors.	Figure 2. A periapical radiograph reveals significant bone loss around the implants and adjacent teeth.
Figure 3. The healed ridge after implant removal.	Figure 4. The ridge is exposed for cortical perforations and harvesting autogenous bone.

Absorbable membranes were developed to overcome some of the disadvantages of non-absorbable membranes. Collagen-based products are the most commonly used absorbable membranes. Absorbable collagen membranes have several advantages, including ease of handling, improved soft-tissue healing, and lower risk of membrane exposure.⁴ They also decrease patient morbidity as they do not require retrieval after healing. The disadvantages of collagen membranes include a lack of space maintenance and a more limited barrier function time compared to non-absorbable membranes. 

Figure 5. Tenting screws were placed in the anterior mandible to support the graft.	Figure 6. The ridge was augmented with particulate autograft, bovine bone mineral, and platelet-rich fibrin.
Figure 7. The collagen membrane is secured with periosteal sutures.	Figure 8. The reconstructed ridge after 6 months of healing.

Absorbable collagen membranes can be made from native collagen or artificially cross-linked. Commercially available collagen membranes provide different resorption times based on the type of collagen and the cross-linking process. It is important to select a membrane that maintains its structural integrity for the time necessary to allow the proliferation and maturation of bone cells within the defect. Although native collagen membranes have desirable handling properties and incorporate well into the tissue bed, this type of membrane degrades more rapidly.⁵ Cross-linking the collagen fibers slows the rate of degradation and maintains structural integrity to prolong barrier function. This feature is important when greater osseous gains are required as longer barrier function is necessary to allow proliferation and maturation of the bone-forming cells. Cross-linking can be produced by either chemical or physical reagents. One of the most widely performed techniques is the use of glutaraldehyde.4 However, glutaraldehyde cross-linking has been shown to elicit a greater inflammatory response and is associated with a higher incidence of wound dehiscence and membrane exposure.^6-8

Figure 9. Exposure of the healed ridge reveals bone gain to the level of tenting screws.	Figure 10. An occlusal view of the healed ridge reveals favorable 3D contour.
Figure 11. Placement of implant No. 27.	Figure 12. Placement of implant No. 25.

Ribose Cross-Link Technology

Glycation uses a non-toxic, naturally occurring sugar (ribose) to cross-link the collagen fibrils while maintaining a high level of biocompatibility. OSSIX Plus collagen membrane (Dentsply Sirona) is an example of an absorbable ribose cross-linked collagen membrane that uses glycation through Dentsply Sirona’s patented GLYMATRIX technology. This membrane is one of the most extensively researched, with more than 100 scientific publications on its use, and offers several advantages for guided bone regeneration. OSSIX Plus is cross-linked to a much higher degree than native or other cross-linked collagen membranes, resulting in a unique resistance to collagenases and a significantly longer barrier function of 4 to 6 months.⁹ This characteristic can have significant clinical advantages, particularly in larger, extrabony defects where prolonged barrier function is necessary. In addition, a graft material with greater biologic activity, such as autogenous bone, is often needed for vertical augmentation.¹⁰ 

Figure 13. An occlusal view of the 2 implants in the reconstructed mandible.	Figure 14. Pre-op view of the failed maxillary implants supporting a fixed bridge.
Figure 15. Periapical radiograph of the maxillary left implant reveals severe marginal bone loss.	Figure 16. The maxillary ridge following healing after implant removal.

A unique property of the OSSIX Plus membrane is the in situ ossification of the collagen. A human histological case series was the first to demonstrate direct mineral apposition on glycated collagen.¹¹ This has also been confirmed in a case series study that showed collagen and bone apposition on the membrane remnants, further demonstrating this membrane’s high grade of biocompatibility.¹² The combination of high biocompatibility and prolonged degradation of the ribose cross-linked membrane results in the integration of the membrane into the local bone as the material serves as a substrate for ossification. 

Figure 17. Exposure of the atrophic maxilla.	Figure 18. A tenting screw is used to support the particulate bone graft and membrane.
Figure 19. The ridge was augmented with particulate autograft, bovine bone mineral, and platelet-rich fibrin.	Figure 20. The graft in the left maxilla was covered with collagen membrane and secured with periosteal sutures.

Figure 21. The graft in the right maxilla was covered with collagen membrane and secured with periosteal sutures.	Figure 22. The reconstructed ridge after 6 months of healing.
Figure 23. Six dental implants were inserted into the reconstructed maxilla.

Ideally, tension-free, primary flap closure is obtained over the graft site. Unlike non-absorbable membranes, exposure of conventional absorbable collagen membranes usually does not result in a serious infection. However, the bacterial contamination of the membrane results in faster degradation and may well compromise bone ingrowth. Studies have demonstrated greater resistance to breakdown by bacterial collagenases with ribose cross-linked collagen membranes after exposure to the oral cavity.¹³ A clinical study comparing native collagen, ePTFE, and ribose cross-link membranes found OSSIX Plus was capable of supporting gingival healing and bone fill even when prematurely exposed.¹⁴ 

CASE REPORTS

Case 1

The patient was a 45-year-old male who had 2 failed implants in the anterior mandible (Nos. 25 and 26) (Figure 1). The periapical radiograph revealed severe bone loss around the implants and the adjacent teeth (Nos. 24 and 27) (Figure 2). The implants and the adjacent teeth were removed, and the area was allowed to heal for 2 months (Figure 3). The anterior mandible was planned for vertical bone augmentation for the placement of 2 implants to support an implant bridge. The ridge was exposed, and cortical perforations were performed in the graft site. A bone-harvesting bur (Auto-Max [Mega’Gen]) was used to procure particulate autograft from the mandibular symphysis (Figure 4). Tenting Screws (Pro-fix) were then inserted to provide added support for the particulate graft and space maintenance (Figure 5). The particulate autograft was mixed with bovine bone mineral (Bio-Oss [Geistlich Pharma]) and platelet-rich fibrin (IntraSpin System [BioHorizons]) (Figure 6). The graft was covered with an OSSIX Plus collagen membrane. Periosteal lasso sutures were then used to secure the membrane (Figure 7). The graft was then allowed to heal for 6 months (Figure 8). Re-entry found significant vertical bone gain and 3D reconstruction of the defect (Figures 9 and 10). Two Bone Level Tapered Implants (Straumann USA) were inserted into the anterior mandible (Nos. 25 and 27) (Figures 11 to 13).

Case 2

The patient was a 56-year-old female who presented with failing maxillary implants supporting a fixed bridge (Figure 14). Periapical radiographs revealed significant marginal bone loss around the implants (Figure 15). The implants were removed, and a temporary complete denture was delivered (Figure 16). Exposure of the maxilla revealed inadequate bone width for implant placement and a significant loss of facial contour (Figure 17). 

Tenting screws were then inserted into the anterior maxilla (Figure 18). The particulate autograft was harvested with a bone scraper and mixed with bovine bone mineral (Bio-Oss) and platelet-rich fibrin (Intra-Spin System) (Figure 19). The graft was covered with OSSIX Plus collagen membranes. Periosteal lasso sutures were then used to secure the membranes (Figures 20 and 21). The graft was then allowed to heal for 6 months. Re-entry found significant vertical bone gain and 3D reconstruction of the defect (Figure 22). Six Straumann Bone Level Tapered Implants were inserted into the maxilla (Figure 23).

CONCLUSION

GBR has become a routine procedure in implant dentistry for predictable regeneration of bone and repair of osseous defects. Barrier membranes should be purposefully selected for each clinical scenario with consideration to their desired features. With several commercially available membranes, it is critical to be aware of their barrier function timeline, handling characteristics, and outcomes in clinical studies.

The OSSIX Plus collagen membrane is supported by evidence-based research and can offer excellent regenerative potential in demanding osseous defects due to its superior barrier function, degradation resistance, and ossification properties. The case examples in this article exhibit its use for horizontal and vertical bone augmentation using GBR with a resorbable membrane. 

REFERENCES

1. Dahlin C, Linde A, Gottlow J, Nyman S. Healing of bone defects by guided tissue regeneration. Plast Reconstr Surg. 1988;81(5):672–6. doi:10.1097/00006534-198805000-00004 

2. Wang HL, Boyapati L. “PASS” principles for predictable bone regeneration. Implant Dent. 2006;15(1):8-17. doi:10.1097/01.id.0000204762.39826.0f

3. Simion M, Baldoni M, Rossi P, et al. A comparative study of the effectiveness of e-PTFE membranes with and without early exposure during the healing period. Int J Periodontics Restorative Dent. 1994;14(2):166-80. 

4. Bunyaratavej P, Wang HL. Collagen membranes: a review. J Periodontol. 2001 Feb;72(2):215-29. doi:10.1902/jop.2001.72.2.215. https://pubmed.ncbi.nlm.nih.gov/11288796/

5. Moses O, Vitrial D, Aboodi G, et al. Biodegradation of three different collagen membranes in the rat calvarium: a comparative study. J Periodontol. 2008;79(5):905–11. doi:10.1902/jop.2008.070361

6. Rothamel D, Schwarz F, Sager M, et al. Biodegradation of differently cross-linked collagen membranes: an experimental study in the rat. Clin Oral Implants Res. 2005;16(3):369-78. doi: 10.1111/j.1600-0501.2005.01108.x

7. Tal H, Kozlovsky A, Artzi Z, et al. Long-term bio-degradation of cross-linked and non-cross-linked collagen barriers in human guided bone regeneration. Clin Oral Implants Res. 2008;19(3):295-302. doi:10.1111/j.1600-0501.2007.01424.x

8. Becker J, Al-Nawas B, Klein MO, et al. Use of a new cross-linked collagen membrane for the treatment of dehiscence-type defects at titanium implants: a prospective, randomized-controlled double-blinded clinical multicenter study. Clin Oral Implants Res. 2009;20(7):742-9. doi:10.1111/j.1600-0501.2008.01689.x 

9. Scheyer ET, McGuire MK. Evaluation of premature membrane exposure and early healing in guided bone regeneration of peri-implant dehiscence and fenestration defects with a slowly resorbing porcine collagen ribose cross-linked membrane: a consecutive case series. Clin Adv Periodontics. 2015;5(3):165-170. doi:10.1902/cap.2014.130080

10. Misch CM, Basma H, Misch-Haring MA, Wang HL. An updated decision tree for vertical bone augmentation. Int J Periodontics Restorative Dent. 2021;41(1):11-21. doi:10.11607/prd.4996 

11. Zubery Y, Nir E, Goldlust A. Ossification of a collagen membrane cross-linked by sugar: a human case series. J Periodontol. 2008;79(6):1101–7. doi:10.1902/jop.2008.070421 

12. Friedmann A, Strietzel FP, Maretzki B, et al. Observations on a new collagen barrier membrane in 16 consecutively treated patients. Clinical and histological findings. J Periodontol. 2001;72(11):1616–23. doi:10.1902/jop.2001.72.11.1616 

13. Klinger A, Asad R, Shapira L, et al. In vivo degradation of collagen barrier membranes exposed to the oral cavity. Clin Oral Implants Res. 2010;21(8):873–6. doi:10.1111/j.1600-0501.2010.01921.x

14. Moses O, Pitaru S, Artzi Z, et al. Healing of dehiscence-type defects in implants placed together with different barrier membranes: a comparative clinical study. Clin Oral Implants Res. 2005;16(2):210–9. doi:10.1111/j.1600-0501.2004.01100.x

ABOUT THE AUTHORS

Dr. Misch received his DDS degree from the University of Michigan in 1985. In 1991, he received certificates in postgraduate prosthodontics and oral implantology as well as a Master of Dental Science degree from the University of Pittsburgh. Dr. Misch then completed a residency in oral and maxillofacial surgery in Pittsburgh. He is board certified by the American Board of Oral and Maxillofacial Surgery as well as the American Board of Oral Implantology/Implant Dentistry. He is a Clinical Associate Professor at the University of Florida, University of Alabama, University of Pennsylvania, and University of Michigan. Dr. Misch serves as editor-in-chief of the International Journal of Oral Implantology and is on the editorial boards of several other dental journals. He practices as a dual specialist at Misch Implant Dentistry in Sarasota, Fla. He can be reached at cmisch@umich.edu.   

Disclosure: Dr. Misch is a consultant for Datum Dental and Dentsply Sirona.

Dr. Misch-Haring is a third-year periodontics resident at the University of Alabama at Birmingham (UAB) School of Dentistry. She received her DMD degree from the UAB School of Dentistry in 2019, graduating as class valedictorian. Dr. Misch-Haring is a member of the Omicron Kappa Upsilon dental society, the American Academy of Periodontology, and the Academy of Osseointegration. She can be reached at mmisch@uab.edu.

Disclosure: Dr. Misch-Haring reports no disclosures.  

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Leena Palomo, DDS, MSD, an accomplished dental educator, clinician, and researcher, has been named chair of the Ashman Department of Periodontology and Implant Dentistry at New York University College of Dentistry (NYU Dentistry), effective September 1, 2021.

Dr. Palomo will join NYU Dentistry from Case Western Reserve University School of Dental Medicine (CWRU), where she is currently a tenured professor of periodontics. She brings over a decade of collaboration with the Cleveland Clinic and the Center for Specialized Women’s Health to her new position. Her research interests include women’s health, aesthetics, and quality of life. She has mentored numerous dental and medical postgraduate students who have received accolades and honors for the quality of their theses.

Through her collaborations, she played a key role in periodontal research and treatment for the rheumatoid spectrum diseases, speaking at many national and international Sjögren’s and rheumatology meetings, and publishing her findings on wellness in multidisciplinary and interprofessional journals. As department chair, she will integrate the knowledge gained through her extensive international collaborations to make the Ashman Department of Periodontology and Implant Dentistry the global leader in both predoctoral and postgraduate periodontology and implant dentistry education.

“I believe that curiosity is fun,” says Dr. Palomo of her teaching philosophy. “We dissect the evidence from periodontal anatomy, microanatomy, current and classic literature, and evaluate what we know, what we think we know, and ask questions about how periodontology impacts overall wellness. These questions drive discovery. There is nothing more satisfying as a dentist than knowing that you have delivered the very best care. So, I love watching students bring evidence-based treatment and state-of-the-art technology, as well as classical findings, chairside to their patients. Together, we keep asking questions, seeking new knowledge, and having fun as lifelong learners.”

Dr. Palomo received her bachelor’s, dental, and master’s in dentistry (periodontology) degrees from CWRU, and a certificate in periodontics, also from CWRU. She earned a certificate in general practice from the St. Elizabeth Health System.

A Diplomate of the American Board of Periodontology (ABP) and longtime examiner for the ABP, Dr. Palomo was recently elected ABP Director. She continues to work with the ABP to define and test the ideal skillset of knowledge, skills, and abilities required of a Diplomate-level periodontist.

“Dr. Palomo’s demonstrated leadership, teaching excellence, research, mentorship, and commitment to collaboration well qualify her to lead our Ashman Department of Periodontology and Implant Dentistry at this time,” said Charles N. Bertolami, DDS, DMedSc, the Herman Robert Fox Dean of NYU Dentistry. “I am confident that she is exactly the right person to lead the department as it seeks to further advance periodontal education, research, and patient care.”

About NYU College of Dentistry
Founded in 1865, New York University College of Dentistry (NYU Dentistry) is the third oldest and the largest dental school in the US, educating nearly 10 percent of the nation’s dentists. NYU Dentistry has a significant global reach with a highly diverse student body. Visit http://dental.nyu.edu for more.

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Dentsply Sirona’s Smart Integration Award recognizes female dentists and dental technicians from around the world who are working in a smartly integrated practice or lab environment and who offer their patients excellent, modern treatment solutions, according to the company. Teresa A. Dolan, DDS, MPH, vice president and chief clinical officer at Dentsply Sirona, discusses the award and why it matters.

Q: The Smart Integration Award by Dentsply Sirona has existed since 2019. How did it come into being?

A: The Smart Integration Award honors extraordinary success stories and innovative ideas of female dentists and dental technicians. Modern dentistry is all about innovation, and technology is changing rapidly. As the leading company in the field of digital dentistry, we always strive to find the best possible solutions in the digital workflows of dentistry practices. The key to our success is communicating with our customers. By asking our customers how connected workflows support efficacy and how they integrate the patients’ needs into treatment, we can find ways to optimize dental treatment.

Q: The Smart Integration Award recognizes female talent in dentistry. What is the specific situation of women in this profession today?

A: Today, more and more women work in the field of dentistry. In many countries, over 50% of students at dental schools are women. The creative potential of women in the profession will shape the future of dentistry, and we are committed to supporting their professional advancement.

The Smart Integration Award and Expert Development Program are tailored to the specific demands of women leaders and innovators. We learned a lot from research on this topic. For example, support in developing professional networks is a priority. So, with the Smart Integration Award, we wanted to establish a platform for building a strong international network of female talent within the profession.  

There is also a considerable demand for education and training that empowers women professionals to open or grow their own practices. We get a lot of positive feedback for the women-centered environment of the competition and network. Many female professionals feel more comfortable in this setting.

Q: How important is it for a company like Dentsply Sirona to consider specific needs of men and women in the field of dentistry?

A: The integration of different perspectives enables us to develop technological solutions holistically. We work with female and male dentists, technicians, hygienists, and team members and learn about their needs in detail so that we can offer relevant innovations that best meet the expectations of our customers. This can be different requirements in terms of ease of use, but also in terms of comfort and ergonomics.

To continuously develop our portfolio, we establish contacts with the most talented dentists from their early career and through their career development. In programs like the Global Clinical Case Contest and SCADA student research competition, we cooperate with universities around the world and provide professional development opportunities for their very talented students, and thus help ensure that the best possible treatment continues to be available to patients in the future.

Q: Dentsply Sirona is continuously investing in dental education programs. What is the focus of these programs?

A: With training and education, we strive to empower dental professionals all over the world. This is part of our purpose and mission as a company. We want our customers and dental professionals to bring forward modern dentistry and deliver the best possible treatments to their patients.

Today, dental professionals can choose from a wide range of in-depth education programs. This education happens online and in-person through Dentsply Sirona Academy and key educational partners. We continue to open new education centers in markets around the world.

With our Women in Dentistry program, we invite professionals to hone their skills in a wide range of topics. With EPIC—Educate, Practice, Innovate and Connect—we introduced the Women’s Dental Meeting in Charlotte, North Carolina, and bring female practitioners from all over the United States together for two days of education centered on CEREC, networking, and building a community of women CEREC users.

Clinical education is part of that foundation upon which the industry moves forward, delivering better oral health care and ultimately improving the lives of patients. The numbers prove that our education and training programs are at the pulse of dental professionals’ needs. In 2020, more than 1 million dental professionals in 80 countries participated in one or more of our 7,289 courses.

Q: What is the process to apply for the Smart Integration Award 2021 as well as the requirements?

A: Registration is open online until June 28. All female dentists are invited to submit their success stories or ideas for improving workflow and/or patient experience through the use of connected products within Imaging, Treatment Centers, Digital, Orthodontics, Endodontics, Dental Conservation, Dental Technology, Hygiene, Implantology, Equipment Management, Design, and User Experience.

The award is open to both women who own their practice as well as women dentists who are employees whether they are specialists or work in a general practice. Participants are free to design their entry however they like using photos, video, text, or sketches.

Q: Will the award presentation be digital, and have you already confirmed a date?

A: While we would be thrilled to be able to meet in person for an award presentation, we will continue to monitor the pandemic situation globally. Safety is our main concern and therefore we will hold off on a decision until a later date.

Dr. Dolan leads Dentsply Sirona’s global clinical affairs and is responsible for its strategic direction. In this role, she oversees professional education activities in accordance with ADA CERP standards and guidelines. She also supports the unique clinical initiatives and strategies of each Dentsply Sirona business unit. Prior to joining Dentsply Sirona in 2013, she worked with the University of Florida College of Dentistry, serving as both a professor and dean. Dr. Dolan is a a Phi Beta Kappa graduate of Rutgers University and earned a DDS degree from the University of Texas. She also holds a master of public health degree from the University of California, Los Angeles. Dr. Dolan’s areas of specialization are in dental public health and health services research, as well as gerontology and geriatric dentistry. Among a multitude of honors, she was a Robert Wood Johnson Foundation Dental Health Services Research Scholar and also completed a Veterans Administration Fellowship in Geriatric Dentistry.

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