Comparison of the Survival Rate Against Fracture of Endodontically Treated Premolars with Exposed Cervical Lesions Restored with Crowns and Resin Composites: A Retrospective Study

Objective: The purpose of this study was to evaluate the effect of coronal restorations on the survival rates against fracture of endodontically treated premolars with exposed cervical lesions and to identify the prognostic factors for fracture. Methods: Data of the endodontically treated premolars with exposed cervical lesions restored with resin composites or crowns between 2011 and 2020 were collected. The presence of a fracture was recorded, and the possible prognostic factors were recorded. Statistical analyses were performed, with a significance level of P<0.05, using a Kaplan-Meier survival analysis, log-rank tests, and Cox proportional hazard models were used to identify the prognostic factors. Results: The survival rates against fracture were not significantly different between the teeth restored with crowns (93.3%) or resin composites (86%) (P=0.05). A high frequency of non-restorable fractures was observed in both groups. Crestal bone reduction to the middle-third of the root was identified as the significant prognostic factor (P<0.05). Conclusion: For endodontically treated premolars with exposed cervical lesions, resin composite restorations provided a high comparable survival rate that was comparable to that of crowns. A higher risk of fracture was found in endodontically treated premolars with crestal bone loss to the middle-third of the root.