Risk Factors for Implant Failure and Peri-Implantitis: A Retrospective Cohort Study.

OBJECTIVES: This retrospective cohort study evaluated patient-, implant-, site-, procedural-, biological-, and prosthesis/mechanics-related factors associated with early and late implant failure and peri-implantitis. MATERIAL AND METHODS: Electronic health record data from a university center were analyzed. Forty patient-, implant/site-, biologic-, and prosthesis-related variables were evaluated in relation to early failure, late failure, and peri-implantitis. Bivariate and survival analyses were performed, followed by mixed-effects regression models appropriate to each outcome. Robustness was assessed via clustered bootstrap resampling, penalized regression, and sensitivity analyses. RESULTS: A total of 264 patients and 554 implants were assessed. Cumulative implant failure was 6.8% (3.4% early; 3.4% late), and peri-implantitis incidence was 7.6%. In multivariable analyses, self-reported penicillin allergy (OR = 7.9; 95% CI: 2.7-23.7) and anterior implant location (OR = 5.4; 95% CI: 2.0-14.0) were associated with higher odds of early implant failure, whereas antihypertensive medication use (OR = 0.26; 95% CI:0.08-0.91) was associated with lower odds (p < 0.05). Late implant failure was associated with hypertension (HR = 2.1; 95% CI: 1.3-3.3), previously grafted sites (HR = 1.4; 95% CI:1.0-1.9), and bone-level implants (HR = 10.4; 95% CI: 5.5-19.5). In cluster-robust sensitivity analysis, the association between bone-level implants and late implant failure was attenuated but remained significant (HR = 3.38; 95% CI: 1.96-5.84). Peri-implantitis was associated with periodontitis (HR = 3.6; 95% CI: 1.89-6.97), excess cement (HR = 2.7; 95% CI: 1.25-5.88), and PLCBL (HR = 2.1; 95% CI: 1.09-4.13) (p < 0.05). Robustness analyses generally supported the direction of the identified associations, although some effect estimates were attenuated. CONCLUSIONS: Implant failure and peri-implantitis are associated with distinct, potentially modifiable patient- and treatment-related factors. Recognition of these factors may help identify patients and implants at increased risk of adverse outcomes.