Factors Associated With Crestal Bone Loss Following Dental Implant Placement in a Longitudinal Follow-up Study

The purpose of this study is to estimate the magnitude of crestal bone loss and to identify factors associated with changes in crestal bone height following placement of dental implants. This was a retrospective cohort study, consisting of a sample derived from the population of patients who had at least 1 dental implant placed in a community practice over a 10-year period. A total of 11 predictor variables were grouped into demographic, related health status, anatomic, implant-specific, and operative categories. The primary outcome variable was a change in crestal bone height (mm) over the course of follow-up. The secondary outcome variable was crestal bone loss at 1 year grouped into 2 categories (bone loss >1.5 mm and <= 1.5 mm). Univariate and multivariate regression mixed-effects models were developed to identify variables associated with crestal bone level changes over time. P values <=.05 were considered statistically significant. The study sample was composed of 85 subjects who received 148 implants. The mean change of the crestal bone was 2.1 +/- 1.5 mm (range = -12.5 to 0.5 mm; median = -1.77 mm). In the multivariate model, none of the variables studied were statistically associated with mean crestal bone loss. Among 84 (66.1%) implants with bone loss >1.5 mm within 1 year, no variables were associated with bone loss in the multivariate model. Of the 11 predictor variables evaluated in this study, none were statistically significant with regard to an increased risk for crestal bone loss or for excessive bone loss within the first year after implant placement.