Incidence and Risk Factors of Peri-Implantitis Over Time-A Prospective Cohort Study.

Aim: This prospective cohort study aimed to evaluate the incidence and risk/protective factors of peri-implantitis over time.

Methods: A university-representative cohort was evaluated at baseline and after a mean follow-up time of 3.9 years. The main outcome was the incidence of peri-implantitis, defined as bone loss > 1 mm between the two examinations in implants showing bleeding on probing. Putative risk/protective factors assessed at baseline were tested through multilevel (mixed-effects) logistic regression analyses.

Results: A total of 73 patients with 322 implants were included. During the follow-up period, 14 implants (4.3%) were lost in 9 patients (12.3%). Incidence of peri-implantitis was observed in 22.2% of patients and 9.4% of implants. In the final multilevel multiple logistic regression model, the following factors were associated with occurrence of peri-implantitis: periodontitis severity (stage IV periodontitis: OR = 41.29; 95% CI: 4.10-415.54), periodontal bone loss/age ratio (> 1: OR = 8.87; 95% CI: 1.47-53.73), smoking (current smokers: OR = 7.84; 95% CI: 1.83-33.50), sleep duration (> 7 h: OR = 19.97; 95% CI: 1.69-236.39), implant location (incisor: OR = 60.60; 95% CI: 4.04-908.33), restoration type (full-arch fixed restorations: OR = 89.84; 95% CI: 3.66-2202.97), and restoration margin location (juxta-marginal: OR = 14.17; 95% CI: 1.20-166.76). Keratinized tissue width assessed at baseline was not associated with incidence of peri-implantitis.

Conclusion: Approximately one in five patients and one in 10 implants experienced incident peri-implantitis over a nearly four-year period. Periodontitis (Stage IV and Grade C), lifestyles (smoking and sleep duration), implant location, and prosthetic factors (restoration type and margin location) emerged as risk factors for peri-implantitis.