A 7-year prospective radiographic evaluation of marginal bone level around two different implant systems: a randomized clinical trial.

OBJECTIVE: The aim of this study was to evaluate the change in marginal bone level radiographically around two different implant systems after 7 years of use. MATERIAL AND METHODS: Twenty fully edentulous patients were included in the study and randomly assigned to two treatment groups of machined surface implants (Branemark, n = 40) and rough-surface implants (Xive, n = 40). The implants were early loaded with individual bar-retained overdentures. All patients were treated by the same surgeon and the same prosthodontist. Clinical and radiographic examinations were conducted at the time of implant loading (baseline) and annually for up to 7 years of use. Measurements to the nearest 0.1 mm were taken at the mesial and distal site, and the average values were calculated for each implant. A three-level mixed-effect analysis of covariance (ANOVA) was used to test the significance of the mean marginal bone change in the two implant groups. RESULTS: The study population consisted of 15 women (75%) and five men (25%) with an average age of 61.6 years. A total of 79 of 80 implants integrated successfully. n = 1 Branemark implant failed after 3 weeks. There was a significant difference (P < 0.001) between the two implant systems at the baseline measurements (0.14 mm Branemark vs. 0.39 mm Xive) and a highly significant difference for the annual bone loss (0.07 mm [Branemark] vs. 0.18 mm [Xive], P < 0.001). CONCLUSION: Both the implant systems are clinically satisfying. Nevertheless, the Branemark group showed a better radiological performance than the Xive group.