RESUMEN
AIM: To investigate, retrospectively over a 1- to 16-year follow-up period, the strength and independence of the association of different patient-, tooth- and surgery-related prognostic variables with the outcome of periradicular surgery. METHODOLOGY: The study cohort included 171 teeth in 154 subjects. Clinical and radiographic measures along with the follow-up period were used to determine the healing outcome. For statistical analysis, results were dichotomized into healed/healing versus asymptomatic function/persistent disease cases. The association between candidate prognostic variables and asymptomatic function/persistent disease was analysed individually and adjusted for confounding using a multivariate binary logistic regression model. RESULTS: The percentage of success (healed/healing cases) was found to be 83.6%, whereas the percentage of failure (asymptomatic function/persistent disease cases) was found to be 16.4%. Whilst univariate analysis revealed a positive association of the presence of preoperative signs/symptoms, unsatisfactory quality of the coronal restoration, pronounced root-end resection bevel and inadequate quality of root-end filling with asymptomatic function/persistent disease, after multivariate binary logistic regression analysis only the unsatisfactory quality of the coronal restoration and inadequate quality of root-end filling were strongly and independently associated with disease status. Confounding and interaction effects between candidate prognostic variables was noted. CONCLUSIONS: The findings of this study suggest that whilst the quality of both the coronal restoration and the root-end filling might be the foremost prognostic variables in periradicular surgery, there are synergistic biological interactive and mutually confounding effects with respect to root-end resection bevel and preoperative signs and/or symptoms that may be also associated with an increased proportion of failures after periradicular surgery.