Retreatment or replacement of previous endodontically treated premolars with recurrent apical periodontitis? An 8-year historical cohort study.

OBJECTIVES: The study evaluated previously-endodontically-treated premolars affected by periapical lesions and/or secondary caries requiring a multidisciplinary decision between (non-surgical) retreatment or extraction and implant replacement over an 8-year minimum follow-up. MATERIALS AND METHODS: The decision-making was performed among a pool of patients attending a University Dental School. All patients presented at least one failing previously endodontically treated premolar. Recorded parameters were: structural conditions (residual coronal-structure, caries), periodontal and endodontic status (CEJ-MBL, initial-PAI, post-presence). Two experienced operators made the decision-making and classified teeth as retreatable and restorable (Endo-group) or suitable for extraction and implant replacement (Implant-group). Logistic regression and Cox-proportional-hazard analyses with clustered-standard-errors compared baseline-characteristics and treatment-outcomes. Odds-ratios (ORs) with 95% confidence-intervals (CIs) were reported for baseline-characteristics. Hazard-ratios (HRs) expressed the association of treatment-groups with time-to-event. RESULTS: Ninety-six patients (n = 124 premolars) were enrolled (49 M;47 F; mean-age 53.1 +/- 11.6 years). The decision-making splitted 54.8% treatments to Endo-group (n = 68) and 45.2% to Implant-group (n = 56). The 8-year survival were 85.1% for Endo-group and 98.2% for Implant-group. The 8-year success were 80.5% and 93.9%. The HR from Cox regression favored Implant-group (HR = 0.12, P = 0.049). The Endo-group showed the highest number of critical complications (15%) due to fractures, despite the healing of lesions. Implant-group had a higher percentage of minor prosthetic complications (14%). CONCLUSIONS: Endo-group demonstrated higher percentage of critical complications compared to Implant-group during the follow-up. Root fractures were accounted as main responsible, while periapical disease did not affect healing, survival and clinical longevity. CLINICAL SIGNIFICANCE: Insufficient crown structure was the major parameter associated with root fracture. In these cases, implant replacement strategy represented an adequate therapy justified by the higher success compared to root canal retreatment.