Implant treatment outcomes at the University of British Columbia graduate periodontics clinic : a retrospective analysis

Objectives: Dental implants have predictable outcomes and high survival rates. However, a small subset of patients experience implant failure. A retrospective review of charts at UBC was conducted to determine how patient-, disease-, site-, surgeon- and implant design-centered risk factors affect the survival of implants. Methods: A review of implants placed between 1989-2006 was completed. Inclusion criteria required a one-year post-placement diagnostic radiograph. Implant failure was defined as the loss or removal of an implant at any time. Bivariate analyses were used to identify variables associated with implant failure. Risk factors with p-values < 0.05 or that were deemed clinically relevant by previous studies were included in stepwise linear multiple regression and logistic regression analyses. Results: Based on the inclusion criteria, 107 patients and 300 implants were included in the study. Follow-up ranged from 1.00 to 19.79 years (mean 4.08 + 2.95 years). At follow-up, 92.3% of implants survived and 84.1% of patients did not experience failure, In the failing implant group, 13.1% of patients had one failed implant and 2.8% of patients had two failed implants. The survival rate of replacement implants was 85.71%. Most factors studied had no statistically significant impact on survival. Only simultaneous sinus augmentation and removable prostheses were significantly associated with failure and guided bone regeneration was significantly associated with survival. In the regression analyses, the predictors showing the largest effect on thread exposure were: implant model, jaw (in favor of mandibular implants), and surface (in favor of rough surfaces). The odds ratio for implant failure was 16.87 for osteotome sinus elevation and 0.288 for decreasing implant width. Conclusions: The survival rate for implants placed at UBC is similar to those reported in the literature. Most variables considered risk factors did not have a statistically significant effect on implant failure. Given the high survival rates of implants, a small sample size does not allow for trends in the data to reach statistical significance, even if a true difference exists.Dentistry, Faculty ofGraduat