Longevity and Risk Factors of Post Restorations after up to 15 Years: A Practice-based Study

Introduction: The aims of this multicenter, practice-based cohort study were to evaluate the success and survival of endodontically treated teeth with post restorations (ETT+Ps) and to analyze factors associated with the longevity of ETT+Ps. Methods: Eight general dental practitioners each placed up to 27 ETT+Ps without any restriction to post materials or dimensions. Only incisors, canines, and premolars were included. At the last follow-up visit, ETT+Ps were considered as successful if the post and the initially placed definitive restoration were sufficient, whereas ETT+ Ps were considered as survived if the post was still in function. Multilevel Cox proportional hazards models were used to evaluate the association between a range of predictors and time until no success and no survival. Results: Overall, 195 endodontic posts in 195 patients were followed up for a mean (95% confidence interval) of 91 (81-101) months; the longest follow-up was 15 years. Of these, 122 ETT+Ps were considered successful (estimated success time = 110 [101-120] months), and 152 ETT+Ps survived [estimated survival time = 133 [124-141] months). Regarding the categories of success and survival, the annual failure rates were 6.0% and 3.3%, respectively. Recementation of old (telescopic) crowns after placing new posts was the only significant predictor for decreased time until failure for both success and survival analyses. By excluding recemented restorations, annual failure rates decreased to 3.5% and 2.1%, respectively. Conclusions: For EET+Ps placed in a private practice setting, high success and survival rates were observed. If old (telescopic) crowns were recemented after new posts were placed, the high risk of subsequent failure should be considered and communicated with patients.