Maintenance Adherence, Periodontitis, and Prosthetic Factors in Peri-Implantitis: A Cohort Study

Implant survival rates are high, yet peri-implantitis and implant failure still compromise long-term treatment success. How maintenance adherence, patient susceptibility, and prosthetic design interact to shape these outcomes in routine practice has not been fully characterized.

This single-center retrospective cohort included 260 patients with 469 implants placed between 2017 and 2023 and followed until June 2026 (median 69.3 months). From documented supportive-care records we classified maintenance adherence as regular (≥ 2 documented visits per year or mean interval ≤ 6 months), irregular (0.5-< 2 visits per year among patients not meeting the absent/lost rule), or absent/lost (< 0.5 visits per year; patients with 0.5-< 0.8 visits per year were assigned to absent/lost only when the chart explicitly documented long-term nonadherence to the planned recall schedule). Periodontitis history was staged according to the 2017 classification. Prosthetic and implant-level factors included keratinized mucosa width, retention type, residual cement, emergence profile, food impaction, and occlusal overload. The primary outcome was peri-implantitis; secondary outcomes included implant failure and marginal bone loss. Generalized estimating equations accounted for implant clustering within patients, and survival was assessed by Kaplan-Meier analysis.

Peri-implantitis developed in 80 implants (17.1%) and implant failure in 18 (3.8%). Compared with regular maintenance, irregular maintenance (adjusted OR: 2.09, 95% CI: 1.08-4.06; p = 0.029) and absent/lost maintenance (adjusted OR: 4.67, 95% CI: 2.21-9.87; p < 0.001) carried progressively higher peri-implantitis risk. Stages III-IV periodontitis (OR: 1.70, 95% CI: 0.87-3.32), keratinized mucosa < 2 mm, suspected residual cement, food impaction, and occlusal overload showed directionally elevated but nonsignificant associations. Longer maintenance intervals were associated with higher peri-implantitis probability in a dose-response fashion, and marginal bone loss was most pronounced when advanced periodontitis and absent/lost maintenance coincided.

Poor maintenance adherence was independently associated with peri-implantitis and greater marginal bone loss. Advanced periodontitis history and site- or prosthesis-related factors showed directionally elevated but statistically nonsignificant adjusted associations with peri-implantitis, while advanced periodontitis remained associated with greater bone loss. These findings support risk-stratified supportive care programs-combining periodontal risk assessment, individualized recall intervals, and systematic prosthetic evaluation during maintenance visits-as a strategy to protect long-term peri-implant health.