Effect of Bruxism on the Clinical Success of Posterior Composite Restorations in Endodontically Treated Teeth: A Cross-Sectional, Case-Control Study.

Abstract

Aim: To determine the effect of bruxism on the success of posterior composite restorations (PCRs) in endodontically treated teeth (ETT).

Methods: This cross-sectional, case-control study included 40 case patients (bruxists with PCR post-ETT) and 40 controls (non-bruxists). A matching case-control model was used based on sex, age, follow-up period, cavity classification, and caries risk group. Potential risk factors affecting restoration success, such as sociodemographic characteristics and clinical findings, were recorded. The PCRs were evaluated according to revised FDI criteria. Fisher's exact test and binary logistic regression analysis were used for statistical evaluation (p < 0.05).

Results: Considering caries at restoration margins (p = 0.007), color match (p = 0.039), dental hard tissue defects at restoration margins (p = 0.001), occlusion and wear (p = 0.001), and surface luster and texture (p = 0.035), bruxists achieved significantly lower success than non-bruxists. Cases had lower overall success than controls (p = 0.001). Bruxism (OR: 1.25, 95% CI: 0.00-1.58), periodontal status (OR: 0.18, 95% CI: 0.03-1.15), TMJ disorders (OR: 0.05, 95% CI: 0.00-1.15), and presence of enamel cracks (OR: 1.67, 95% CI: 0.00-1.68) significantly affected restoration success (p < 0.05).

Conclusion: Bruxism significantly affects functional, esthetic, and biological success of PCRs in ETT. In bruxists, PCRs in small/medium-sized cavities failed primarily because of wear, followed by color mismatching, roughness, caries, and dental hard tissue fractures.

Trial registration: ClinicalTrials.gov identifier: NCT06881355.