Marginal Bone Response of Submerged and Nonsubmerged Osteoconductive Alkali-Etched Implants in Thick and Thin Biotypes: A 2-year Clinical Follow-up Study

Purpose: This follow-up study evaluated the implant success rate and marginal bone response of submerged and nonsubmerged osteoconductive two-piece implants with a moderately rough implant neck in thick and thin gingival biotypes. Materials and Methods: The stability of the hard tissue surrounding the implants was evaluated, based on clinical and radiographic examinations performed after implant placement and every follow-up thereafter. The clinical data were processed via linear mixed-effects model statistics at the patient level. Results: Forty-three edentulous and partially edentulous patients were treated with a total of 97 implants with an osteoconductive surface. After 2 years in function, all the implants and dental prostheses reached a 100% success rate according to predefined criteria. Taking implantation as a baseline, the mean change in the marginal bone level (Delta MBLp) after 2 years in function was -0.36 mm (SD: 0.55), and bone resorption higher than 1 mm and less than 2.5 mm was observed for seven implants. Taking dental prosthesis placement as a baseline, the Delta MBLp after 2 years of loading was -0.13 mm (SD: 0.39), and bone resorption higher than 1 mm and less than 2.0 mm was observed only for two implants. Statistically significant differences in mean marginal bone loss were observed in the gingival biotype (P = .006) and submersion (P < .05). Their influence on the dynamics of peri-implant bone loss during the process of biologic width restoration was analyzed. Conclusion: This study demonstrated the high stability of peri-implant hard tissue and the 100% success rate of the implant system with a moderately rough neck. The biotype and implant submersion were evaluated as factors having a significant influence on marginal bone loss.