The International Journal of Periodontics & Restorative Dentistry © 2014 BY QUINTESSENCE PUBLISHING CO, INC. PRINTING OF THIS DOCUMENT IS RESTRICTED TO PERSONAL USE ONLY. NO PART MAY BE REPRODUCED OR TRANSMITTED IN ANY FORM WITHOUT WRITTEN PERMISSION FROM THE PUBLISHER.
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Human Histologic Assessment of a Platform-Switched Osseointegrated Dental Implant Myron Nevins, DDS1 Marcelo Camelo, DDS2 Samuel Koo, DDS, MS3 Richard J. Lazzara, DDS, MScD4 David M. Kim, DDS, DMSc5 This case report examined crestal bone level maintenance surrounding a platform-switched implant that was retrieved due to prosthetic difficulty. The retrieved platform-switched implant threads demonstrated tight contact with the surrounding bone and demonstrated both radiographic and histologic features that were indicative of successful osseointegration. Very high boneto-implant contact (BIC) without epithelial downgrowth to the implant thread was noted. The BIC consisted of a combination of newly formed bone and native bone. The buccal and lingual bone levels coincided with the original platform position noted at the time of the surgery, and did not appear to resorb at all. The result of the present investigation confirms the maintenance of the crestal bone level for platform-switched implants. (Int J Periodontics Restorative Dent 2014;34(suppl):s71–s73. doi: 10.11607/prd.1651)
Associate Clinical Professor, Division of Periodontology, Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, Massachusetts, USA. 2Institute for Advanced Dental Studies, Belo Horizonte, Brazil. 3Postdoctoral Resident and Research Fellow, Division of Periodontology, Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, Massachusetts, USA. 4Private Practice, West Palm Beach, Florida, USA. 5Assistant Professor, Division of Periodontology, Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, Massachusetts, USA. 1
Correspondence to: Dr Myron Nevins, Harvard School of Dental Medicine, Department of Oral Medicine, Infection and Immunity, 188 Longwood Avenue, Boston, MA 02115; email: [email protected]. ©2014 by Quintessence Publishing Co Inc.
The maintenance of the crestal bone level surrounding dental implants is important for providing long-term success and an esthetic outcome. Vertical bone loss of 1.5 to 2.0 mm typically occurs after prosthetic loading.1 The amount of crestal bone remodeling was reduced when a mismatched abutment was inadvertently used in a wide platform implant.2 A number of studies revealed inflammatory infiltrates at the implant-abutment junction and concluded that the presence of inflammatory infiltrates resulted in cervical bone loss.3,4 The platform-switching approach shifts the implant-abutment junction inwardly (in a horizontal direction) and reduces the effect of inflammatory cell infiltrate.2 Several clinical studies have confirmed reduced marginal bone resorption with platform-switching implants.5–9 However, histologic evidence of tissue surrounding platform-switched implants in humans remains sparse.10,11 The current case report examines the periimplant hard tissue around a platform-switched implant retrieved due to prosthetic difficulty.
Volume 34, Supplement, 2014 © 2014 BY QUINTESSENCE PUBLISHING CO, INC. PRINTING OF THIS DOCUMENT IS RESTRICTED TO PERSONAL USE ONLY. NO PART MAY BE REPRODUCED OR TRANSMITTED IN ANY FORM WITHOUT WRITTEN PERMISSION FROM THE PUBLISHER.
s72
Fig 1 Three dental implants have been placed in the mandibular right posterior quadrant.
Fig 2 Micro-CT evaluation demonstrating high BIC.
to its improper angulation, and removal was recommended. The patient agreed with the proposal and consented to donate her implant for research investigation. The harvested platform-switched implant, together with surrounding bone and soft tissue, was processed for microcomputed tomographic (micro-CT) and histologic examinations (Fig 1). The remaining two implants were successfully used as abutments for a three-unit implant-supported fixed partial denture.
Micro-CT and light microscopy
100 μm
200 μm
Fig 3 Light microscopy of retrieved platform-switched implant, demonstrating maintenance of the crestal bone level.
Fig 4 Magnified view of the implant threads demonstrating excellent BIC.
Case report
plant (mandibular right first and second premolars and first molar sites) platforms at the crestal bone level. No grafting was required in conjunction with implant placement. Healing abutments were placed for all three implants and surgical flaps were sutured to insert implants in a single-stage approach. The impression for the fabrication of the definitive restorations was planned after a 6-month healing period. However, the platform-switched middle implant (NanoTite Certain Prevail 4/3 × 8.5 mm, Biomet 3i) was deemed to be unrestorable due
A healthy 62-year-old woman presented for treatment of her partially edentulous mandibular posterior ridge. The radiographic survey revealed sufficient bone for the placement of three implants. A full-thickness mucoperiosteal flap was reflected after midcrestal incision. The implant site osteotomy was performed following the manufacturer’s guidelines, and three dental implants (NanoTite Certain Prevail, Biomet 3i) were placed. An attempt was made to position all im-
The platform-switched implant threads demonstrated tight contact with the surrounding bone, as well as both radiographic and histologic features that were indicative of successful osseointegration (Figs 2 and 3). Very high bone-to-implant contact (BIC) without epithelial downgrowth to the implant thread was noted (Fig 4). The BIC consisted of a combination of newly formed bone and native bone. The buccal and lingual bone levels coincided with the original platform position (see Figs 1 and 3), noted at the time of the surgery, and did not appear to resorb at all. The vertical bone levels in the specimen raise the possibility of new thought processes that can be achieved with the NanoTite surface implant. The buccal aspect of the implant demonstrated complete osseointegration, including 100% of the threads. The lingual surface demonstrated complete coverage of
The International Journal of Periodontics & Restorative Dentistry © 2014 BY QUINTESSENCE PUBLISHING CO, INC. PRINTING OF THIS DOCUMENT IS RESTRICTED TO PERSONAL USE ONLY. NO PART MAY BE REPRODUCED OR TRANSMITTED IN ANY FORM WITHOUT WRITTEN PERMISSION FROM THE PUBLISHER.
s73 threads, and the bone extended vertically onto the collar of the implant.
Discussion In this case report, both micro-CT and histologic evaluations demonstrated a stable crestal bone position surrounding a platformswitched implant that was retrieved 6 months after placement. Several preclinical studies have investigated the influence of mismatched abutments on the crestal bone level, but conflicting results have been reported.12–14 Minimal bone loss was observed when implants with nonmatching implant-abutment diameters were placed above the alveolar crest in canines.12,13,15 Human histologic en bloc evidence remains the ultimate approach to evaluating the soft and hard tissue response around implants.16 Few studies have reported the histologic evidence of bone surrounding platform-switched implants in humans.10,11,17 A high BIC with minimal bone loss was noted on 29 immediately loaded platform-switched implants that had been retrieved after 2 to 10 months of function.17 This implant has a NanoTite finish, including the entire collar. The bone in contact with the collar stains more darkly than the native bone adjacent to it, indicating that bone developed during the osseointegration process. This would be consistent with the new bone having more protein content and, therefore, darker staining compared with the native bone. The interpretation of the results would appear to
create the possibility that platformswitched implants with NanoTite surfaces on the collar would encourage osseointegration to occur on the collar of the implant. The observations from this case report should be interpreted with caution due to lack of prosthetic loading. Future histologic reports of long-term platform-switched implants with functional loading would be desirable.
Conclusions The result of the present investigation supports the use of platformswitched implants to maintain the crestal bone level.
Acknowledgments The authors would like to thank Biomet 3i for supporting the micro-CT and histologic analyses.
References 1. Albrektsson T, Zarb G, Worthington P, Eriksson AR. The long-term efficacy of currently used dental implants: A review and proposed criteria of success. Int J Oral Maxillofac Implants 1986;1:11–25. 2. Lazzara RJ, Porter SS. Platform switching: A new concept in implant dentistry for controlling postrestorative crestal bone level. Int J Periodontics Restorative Dent 2006;26:9–17. 3. Ericcson I, Persson LG, Berglundh T, Marinello CP, Lindhe J, Klinge B. Different types of inflammatory reactions in peri-implant soft tissues. J Clin Periodontol 1995;22:255–261. 4. Berglundh T, Lindhe J. Dimension of the periimplant mucosa. Biological width revisited. J Clin Periodontol 1996;23:971–973. 5. Cappiello M, Luongo R, Di Iorio D, Bugea C, Cocchetto R, Celletti R. Evaluation of periimplant bone loss around platform-switched implants. Int J Periodontics Restorative Dent 2008;28:347–355.
6. Prosper L, Redaelli S, Pasi M, Zarone F, Radaelli G, Gherlone EF. A randomized prospective multicenter trial evaluating the platform-switching technique for the prevention of postrestorative crestal bone loss. Int J Oral Maxillofac Implants 2009;24:299–308. 7. Canullo L, Iurlaro G, Iannello G. Double-blind randomized controlled trial study on postextraction immediately restored implants using the switching platform concept: Soft tissue response. Preliminary report. Clin Oral Implants Res 2009;20:414–420. 8. Canullo L, Fedele GR, Iannello G, Jepsen S. Platform switching and marginal bone-level alterations: The results of a randomizedcontrolled trial. Clin Oral Implants Res 2010; 21:115–121. 9. Al-Nsour MM, Chan HL, Wang HL. Effect of the platform-switching technique on preservation of peri-implant marginal loss: A systematic review. Int J Oral Maxillofac Implants 2012;27:138–145. 10. Degidi M, Iezzi G, Scarano A, Piattelli A. Immediately loaded titanium implant with a tissue- stabilizing/maintaining design (“beyond platform switch”) retrieved from man after 4 weeks: A histological and histomorphometrical evaluation. A case report. Clin Oral Implants Res 2008;19:276–282. 11. Luongo R, Traini T, Guidone PC, Bianco G, Cocchetto R, Celletti R. Hard and soft tissue responses to the platform-switching technique. Int J Periodontics Restorative Dent 2008; 28:551–557. 12. Jung RE, Jones AA, Higginbottom FL, et al. The influence of non-matching implant and abutment diameters on radiographic crestal bone levels in dogs. J Periodontol 2008;79: 260–270. 13. Cochran DL, Bosshardt DD, Grize L, et al. Bone response to loaded implants with nonmatching implant-abutment diameters in the canine mandible. J Periodontol 2009;80: 609–617. 14. Rodríguez X, Vela X, Calvo-Guirado JL, Nart J, Stappert CF. Effect of platform switching on collagen fiber orientation and bone resorption around dental implants: A preliminary histologic animal study. Int J Oral Maxillofac Implants 2012;27:1116–1122. 15. Hermann JS, Cochran DL, Nummikoski PV, Buser D. Crestal bone changes around titanium implants. A radiographic evaluation of uploaded nonsubmerged and submerged implants in the canine mandible. J Periodontol 1997;68:1117–1130. 16. Nevins M. Should we continue to perform human histologic en bloc investigations [editorial]? Int J Periodontics Restorative Dent 2006;26:525. 17. Romanos GE, Testori T, Degidi M, Piatelli A. Histologic and histomorphometric findings from retrieved, immediately occlusally loaded implants in humans. J Periodontol 2005;76:1823–1832.
Volume 34, Supplement, 2014 © 2014 BY QUINTESSENCE PUBLISHING CO, INC. PRINTING OF THIS DOCUMENT IS RESTRICTED TO PERSONAL USE ONLY. NO PART MAY BE REPRODUCED OR TRANSMITTED IN ANY FORM WITHOUT WRITTEN PERMISSION FROM THE PUBLISHER.
s71
Human Histologic Assessment of a Platform-Switched Osseointegrated Dental Implant Myron Nevins, DDS1 Marcelo Camelo, DDS2 Samuel Koo, DDS, MS3 Richard J. Lazzara, DDS, MScD4 David M. Kim, DDS, DMSc5 This case report examined crestal bone level maintenance surrounding a platform-switched implant that was retrieved due to prosthetic difficulty. The retrieved platform-switched implant threads demonstrated tight contact with the surrounding bone and demonstrated both radiographic and histologic features that were indicative of successful osseointegration. Very high boneto-implant contact (BIC) without epithelial downgrowth to the implant thread was noted. The BIC consisted of a combination of newly formed bone and native bone. The buccal and lingual bone levels coincided with the original platform position noted at the time of the surgery, and did not appear to resorb at all. The result of the present investigation confirms the maintenance of the crestal bone level for platform-switched implants. (Int J Periodontics Restorative Dent 2014;34(suppl):s71–s73. doi: 10.11607/prd.1651)
Associate Clinical Professor, Division of Periodontology, Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, Massachusetts, USA. 2Institute for Advanced Dental Studies, Belo Horizonte, Brazil. 3Postdoctoral Resident and Research Fellow, Division of Periodontology, Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, Massachusetts, USA. 4Private Practice, West Palm Beach, Florida, USA. 5Assistant Professor, Division of Periodontology, Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, Massachusetts, USA. 1
Correspondence to: Dr Myron Nevins, Harvard School of Dental Medicine, Department of Oral Medicine, Infection and Immunity, 188 Longwood Avenue, Boston, MA 02115; email: [email protected]. ©2014 by Quintessence Publishing Co Inc.
The maintenance of the crestal bone level surrounding dental implants is important for providing long-term success and an esthetic outcome. Vertical bone loss of 1.5 to 2.0 mm typically occurs after prosthetic loading.1 The amount of crestal bone remodeling was reduced when a mismatched abutment was inadvertently used in a wide platform implant.2 A number of studies revealed inflammatory infiltrates at the implant-abutment junction and concluded that the presence of inflammatory infiltrates resulted in cervical bone loss.3,4 The platform-switching approach shifts the implant-abutment junction inwardly (in a horizontal direction) and reduces the effect of inflammatory cell infiltrate.2 Several clinical studies have confirmed reduced marginal bone resorption with platform-switching implants.5–9 However, histologic evidence of tissue surrounding platform-switched implants in humans remains sparse.10,11 The current case report examines the periimplant hard tissue around a platform-switched implant retrieved due to prosthetic difficulty.
Volume 34, Supplement, 2014 © 2014 BY QUINTESSENCE PUBLISHING CO, INC. PRINTING OF THIS DOCUMENT IS RESTRICTED TO PERSONAL USE ONLY. NO PART MAY BE REPRODUCED OR TRANSMITTED IN ANY FORM WITHOUT WRITTEN PERMISSION FROM THE PUBLISHER.
s72
Fig 1 Three dental implants have been placed in the mandibular right posterior quadrant.
Fig 2 Micro-CT evaluation demonstrating high BIC.
to its improper angulation, and removal was recommended. The patient agreed with the proposal and consented to donate her implant for research investigation. The harvested platform-switched implant, together with surrounding bone and soft tissue, was processed for microcomputed tomographic (micro-CT) and histologic examinations (Fig 1). The remaining two implants were successfully used as abutments for a three-unit implant-supported fixed partial denture.
Micro-CT and light microscopy
100 μm
200 μm
Fig 3 Light microscopy of retrieved platform-switched implant, demonstrating maintenance of the crestal bone level.
Fig 4 Magnified view of the implant threads demonstrating excellent BIC.
Case report
plant (mandibular right first and second premolars and first molar sites) platforms at the crestal bone level. No grafting was required in conjunction with implant placement. Healing abutments were placed for all three implants and surgical flaps were sutured to insert implants in a single-stage approach. The impression for the fabrication of the definitive restorations was planned after a 6-month healing period. However, the platform-switched middle implant (NanoTite Certain Prevail 4/3 × 8.5 mm, Biomet 3i) was deemed to be unrestorable due
A healthy 62-year-old woman presented for treatment of her partially edentulous mandibular posterior ridge. The radiographic survey revealed sufficient bone for the placement of three implants. A full-thickness mucoperiosteal flap was reflected after midcrestal incision. The implant site osteotomy was performed following the manufacturer’s guidelines, and three dental implants (NanoTite Certain Prevail, Biomet 3i) were placed. An attempt was made to position all im-
The platform-switched implant threads demonstrated tight contact with the surrounding bone, as well as both radiographic and histologic features that were indicative of successful osseointegration (Figs 2 and 3). Very high bone-to-implant contact (BIC) without epithelial downgrowth to the implant thread was noted (Fig 4). The BIC consisted of a combination of newly formed bone and native bone. The buccal and lingual bone levels coincided with the original platform position (see Figs 1 and 3), noted at the time of the surgery, and did not appear to resorb at all. The vertical bone levels in the specimen raise the possibility of new thought processes that can be achieved with the NanoTite surface implant. The buccal aspect of the implant demonstrated complete osseointegration, including 100% of the threads. The lingual surface demonstrated complete coverage of
The International Journal of Periodontics & Restorative Dentistry © 2014 BY QUINTESSENCE PUBLISHING CO, INC. PRINTING OF THIS DOCUMENT IS RESTRICTED TO PERSONAL USE ONLY. NO PART MAY BE REPRODUCED OR TRANSMITTED IN ANY FORM WITHOUT WRITTEN PERMISSION FROM THE PUBLISHER.
s73 threads, and the bone extended vertically onto the collar of the implant.
Discussion In this case report, both micro-CT and histologic evaluations demonstrated a stable crestal bone position surrounding a platformswitched implant that was retrieved 6 months after placement. Several preclinical studies have investigated the influence of mismatched abutments on the crestal bone level, but conflicting results have been reported.12–14 Minimal bone loss was observed when implants with nonmatching implant-abutment diameters were placed above the alveolar crest in canines.12,13,15 Human histologic en bloc evidence remains the ultimate approach to evaluating the soft and hard tissue response around implants.16 Few studies have reported the histologic evidence of bone surrounding platform-switched implants in humans.10,11,17 A high BIC with minimal bone loss was noted on 29 immediately loaded platform-switched implants that had been retrieved after 2 to 10 months of function.17 This implant has a NanoTite finish, including the entire collar. The bone in contact with the collar stains more darkly than the native bone adjacent to it, indicating that bone developed during the osseointegration process. This would be consistent with the new bone having more protein content and, therefore, darker staining compared with the native bone. The interpretation of the results would appear to
create the possibility that platformswitched implants with NanoTite surfaces on the collar would encourage osseointegration to occur on the collar of the implant. The observations from this case report should be interpreted with caution due to lack of prosthetic loading. Future histologic reports of long-term platform-switched implants with functional loading would be desirable.
Conclusions The result of the present investigation supports the use of platformswitched implants to maintain the crestal bone level.
Acknowledgments The authors would like to thank Biomet 3i for supporting the micro-CT and histologic analyses.
References 1. Albrektsson T, Zarb G, Worthington P, Eriksson AR. The long-term efficacy of currently used dental implants: A review and proposed criteria of success. Int J Oral Maxillofac Implants 1986;1:11–25. 2. Lazzara RJ, Porter SS. Platform switching: A new concept in implant dentistry for controlling postrestorative crestal bone level. Int J Periodontics Restorative Dent 2006;26:9–17. 3. Ericcson I, Persson LG, Berglundh T, Marinello CP, Lindhe J, Klinge B. Different types of inflammatory reactions in peri-implant soft tissues. J Clin Periodontol 1995;22:255–261. 4. Berglundh T, Lindhe J. Dimension of the periimplant mucosa. Biological width revisited. J Clin Periodontol 1996;23:971–973. 5. Cappiello M, Luongo R, Di Iorio D, Bugea C, Cocchetto R, Celletti R. Evaluation of periimplant bone loss around platform-switched implants. Int J Periodontics Restorative Dent 2008;28:347–355.
6. Prosper L, Redaelli S, Pasi M, Zarone F, Radaelli G, Gherlone EF. A randomized prospective multicenter trial evaluating the platform-switching technique for the prevention of postrestorative crestal bone loss. Int J Oral Maxillofac Implants 2009;24:299–308. 7. Canullo L, Iurlaro G, Iannello G. Double-blind randomized controlled trial study on postextraction immediately restored implants using the switching platform concept: Soft tissue response. Preliminary report. Clin Oral Implants Res 2009;20:414–420. 8. Canullo L, Fedele GR, Iannello G, Jepsen S. Platform switching and marginal bone-level alterations: The results of a randomizedcontrolled trial. Clin Oral Implants Res 2010; 21:115–121. 9. Al-Nsour MM, Chan HL, Wang HL. Effect of the platform-switching technique on preservation of peri-implant marginal loss: A systematic review. Int J Oral Maxillofac Implants 2012;27:138–145. 10. Degidi M, Iezzi G, Scarano A, Piattelli A. Immediately loaded titanium implant with a tissue- stabilizing/maintaining design (“beyond platform switch”) retrieved from man after 4 weeks: A histological and histomorphometrical evaluation. A case report. Clin Oral Implants Res 2008;19:276–282. 11. Luongo R, Traini T, Guidone PC, Bianco G, Cocchetto R, Celletti R. Hard and soft tissue responses to the platform-switching technique. Int J Periodontics Restorative Dent 2008; 28:551–557. 12. Jung RE, Jones AA, Higginbottom FL, et al. The influence of non-matching implant and abutment diameters on radiographic crestal bone levels in dogs. J Periodontol 2008;79: 260–270. 13. Cochran DL, Bosshardt DD, Grize L, et al. Bone response to loaded implants with nonmatching implant-abutment diameters in the canine mandible. J Periodontol 2009;80: 609–617. 14. Rodríguez X, Vela X, Calvo-Guirado JL, Nart J, Stappert CF. Effect of platform switching on collagen fiber orientation and bone resorption around dental implants: A preliminary histologic animal study. Int J Oral Maxillofac Implants 2012;27:1116–1122. 15. Hermann JS, Cochran DL, Nummikoski PV, Buser D. Crestal bone changes around titanium implants. A radiographic evaluation of uploaded nonsubmerged and submerged implants in the canine mandible. J Periodontol 1997;68:1117–1130. 16. Nevins M. Should we continue to perform human histologic en bloc investigations [editorial]? Int J Periodontics Restorative Dent 2006;26:525. 17. Romanos GE, Testori T, Degidi M, Piatelli A. Histologic and histomorphometric findings from retrieved, immediately occlusally loaded implants in humans. J Periodontol 2005;76:1823–1832.
Volume 34, Supplement, 2014 © 2014 BY QUINTESSENCE PUBLISHING CO, INC. PRINTING OF THIS DOCUMENT IS RESTRICTED TO PERSONAL USE ONLY. NO PART MAY BE REPRODUCED OR TRANSMITTED IN ANY FORM WITHOUT WRITTEN PERMISSION FROM THE PUBLISHER.
