A split-mouth comparative study up to 16 years of two screw-shaped titanium implant systems

P>Introduction Many studies have dealt with the clinical outcome of oral implants, yet none applied a randomized split-mouth design for a long-term follow-up of similar implant systems. Aim To evaluate two oral implant systems with different surface characteristics in a randomized split-mouth design and to radiologically analyse peri-implant bone level and density over an up to 16-year period. Materials and Methods The study comprised clinical and radiographic records of 18 partially edentulous patients treated with both implant types randomly placed in either left or right jaw sides. Outcome was evaluated over time. Results Clinical and radiographic parameters showed no significant differences over time for both systems. Ten years after implant placement, a significantly increasing peri-implant bone density was noted, while Periotest values were found to be significantly decreasing. Fifteen years after implant loading, mean bone loss was 0.02 mm (range -1.15 to 1.51; SD 0.45) for Astra Tech (R) implants (n=24) and 0.31 mm (range -0.98 to 2.31; SD 0.69) for Branemark (R) implants (n=23). Conclusions The study failed to demonstrate significant differences in the outcome of the peri-implant bone for two implant systems with different surface characteristics. The marginal bone level around oral implants changed < 0.5 mm after 15 years of loading.