Survival rates and bone level changes around porous oxide-coated implants (TiUnite).

PURPOSE: This prospective study evaluated implant survival rates and crestal bone changes for porous oxide-coated (TiUnite, Nobel Biocare AB, Gothenburg, Sweden), parallel-walled implants. MATERIALS AND METHODS: All patients receiving TiUnite (porous oxide-surfaced implants [POS]) implants were entered into a database (Triton Tracking System) starting February 1999. Survival rates were calculated from the date of implant placement and related to surgical method of placement (two-stage buried, flapless, immediate placement, immediate placement flapless, one stage), bone quality, and implant characteristics. Failed and nonfailed implants were compared with respect to changes in mean proximal bone levels and the presence of radiolucent areas around the implant apex (shadows). RESULTS: Four hundred nine patients received 817 porous oxide-coated implants, of which 38 failed. Using the last office visit as the censoring date, the cumulative survival date was 93%. The failure rate was independent of bone quality or quantity; implant diameter or length; and surgical method. For the 102 surviving implants, there was no significant change in the average crestal bone loss (+0.13 mm with a standard error, 0.17). For the 17 failing implants, the average crestal bone loss was -4.14 mm (standard error, 0.55). This difference between bone levels of failing and nonfailing implants was highly significant (p < .0001). There was no difference in the prevalence of radiographic shadows around failing and nonfailing implants at time of placement (p < .16). CONCLUSION: Results from this prospective clinical study indicate that 7% of TiUnite surfaced implants failed for unknown reasons. Failing implants were characterized by significant bone loss but not by the presence of shadows.