Peri-implant tissue behaviour next to different titanium surfaces: 16-year post-trial follow-up

The present post-trial follow-up investigated the influence of titanium implants with different surface treatments on clinical behavior of soft and hard peri-implant tissues. Each of the 18 included patients received at least two adjacent implants: one control implant with a dual acid-etched (DAE) surface in their apical portion and a machined coronal part, and one test implant with a DAE surface up to its coronal portion. Peri-implant bone level change (BLC), probing depth (PD), bleeding on probing (BOP) and plaque index (PI) were recorded. A total of 42 implants was inserted. The mean follow-up period was 9.3 years (range: 5–16 years) and there were six dropouts. No implant failed. Moderate crestal bone remodeling occurred during the first year after implant insertion, with lower bone loss next to test implants compared to control ones (0.80 vs. 1.39 mm; p = 0.002). This difference was also detected at the 5-(p = 0.011), 6-(p = 0.008) and 7-year follow-up appointment (p = 0.027). No statistically significant differences were found in bone resorption between implants rehabilitated with ceramic vs. composite resin veneering material. No statistically significant differences were detected between test and control implants for BOP, PI, and PD at any time point. The results of the present study suggest that DAE surfaces reduce peri-implant bone loss in the initial phase of healing compared to machined surfaces, while they do not significantly affect soft peri-implant tissue and bone maintenance in the long-term. In conclusion, the minimally rough surfaces favour peri-implant bone maintenance and their effect is greater in the first year post implant insertion.