Marginal Bone Level Changes in Implant-Supported Fixed Prostheses in a Retrospective Study: A Multifactorial Analysis

Abstract

OBJECTIVE: To identify the site-related, implant characteristic-related, prosthetic, and patient-related factors associated with marginal bone level around dental implant-supported fixed prostheses. MATERIALS AND METHODS: This cross-sectional study analyzed clinical and radiographic data obtained during maintenance visits. The interproximal radiographic bone levels were selected at the site showing the greatest bone loss. The implants were classified as having a bone level ≥ 2 mm (BL group) or < 2 mm (NBL group). Multivariate multilevel logistic regression was used to assess the association between multiple factors and bone level ≥ 2 mm. RESULTS: A total of 196 subjects with 404 implants were included, with a mean follow-up period of 5.21 years. Implementing multifactorial analysis, the results demonstrated that probing depth ≥ 6 mm (odds ratios [OR] 5.39; 95% confidence intervals [CI] 1.21-24.06; p = 0.027), absence of keratinized mucosa (OR 3.54; 95% CI 1.11-11.28; p = 0.033), presence of an implant abutment microgap (OR 2.82; 95% CI 1.12-7.12; p = 0.028), transmucosal height < 2 mm (OR 4.79; 95% CI 1.85-12.41; p = 0.001), and a history of periodontitis (OR 2.80; 95% CI 1.08-7.24; p = 0.034) exhibited a significantly higher risk of marginal bone level ≥ 2 mm. CONCLUSION: Marginal bone level around implant-supported prostheses was influenced by the interplay of multiple factors consisting of deep probing depth, absence of keratinized mucosa, inadequate transmucosal height, microgap configuration, and history of periodontitis. These findings emphasized the need for comprehensive peri-implant assessment, which included monitoring probing depths and soft tissue quality. Additionally, it was crucial to ensure that prostheses were well-designed and had the appropriate transmucosal height. Patients with a history of periodontitis were advised to follow a strict maintenance program. Further prospective studies are needed to confirm the causality for ongoing investigation into the specific aspects and mechanisms involved.