Clinical factors associated with peri-implantitis and the culture-based microbiological profile of peri-implantitis cases: a retrospective matched case-control study

Abstract

Background Peri-implantitis is a biofilm-associated inflammatory disease that can compromise peri-implant tissue stability and implant survival. This study separately examined clinical indicators in a matched case-control analysis and described culture findings among peri-implantitis cases; the microbiological component was not designed to compare disease with health. Methods This retrospective matched case-control study included consecutive adults receiving dental implant treatment between June 2021 and June 2025. Cases met the 2017 World Workshop case definition for peri-implantitis (n = 128), whereas controls without peri-implantitis were selected at a 1:2 ratio (n = 256) by matching on index year and observation time. Microbiological sampling was performed only in cases at disease presentation. All 128 cases were retained in the clinical analyses regardless of culture result; organism-distribution and susceptibility summaries were limited to culture-positive episodes. Clinical associations were evaluated using a post hoc exploratory multivariable logistic regression model. Results Among the 128 peri-implantitis cases, bacterial growth was recovered from 112 episodes (87.5%), whereas 16 episodes (12.5%) were culture-negative. No single organism predominated; the four most frequently recovered taxa each occurred in 19.6%-28.6% of culture-positive episodes. These frequencies are descriptive of cases only. In the matched clinical comparison, history of periodontitis was associated with peri-implantitis (adjusted OR 1.93, 95% CI 1.25-2.99). The larger estimate for immune-related disorders was imprecise (adjusted OR 5.84, 95% CI 1.67-20.47). Anodized implant surface, longer surgery duration, pre-index occlusal overload, higher pre-index plaque index, and fewer maintenance visits were also retained in the exploratory model. Conclusions Culture results describe viable organisms recovered from peri-implantitis cases under the study conditions and do not permit comparison with healthy implants. History of periodontitis was associated with peri-implantitis (adjusted OR 1.93, 95% CI 1.25-2.99); other model estimates remain exploratory because the covariates were selected post hoc, some exposures were sparse, and the analysis was not validated.