The Incidence of Root Canal Therapy after Full-Coverage Restorations: A 10-Year Retrospective Study.

INTRODUCTION:The process of restoring a tooth with a crown leaves many opportunities for pulpal irritation. The objective of this study was to identify and analyze the factors that contribute to the incidence of nonsurgical root canal therapy (NS-RCT) after the delivery of single-unit full-coverage restorations. METHODS:Insurance claims from 88,409 crown placements in the Delta Dental of Wisconsin insurance database were analyzed from the years 2008-2017. The Cox regression model was used to analyze the effect of the predictor variables on the survival of the tooth. Untoward events were defined as NS-RCT, tooth extraction, retreatment of root canal, or apicoectomy as defined by the Code on Dental Procedures and Nomenclature. RESULTS:Of 88,409 crowns placed, 8.97% were complete metal, 41.40% were all ceramic, and 49.64% were porcelain fused to metal (PFM). The probability of survival of all teeth with crowns placed was 90.41% after 9 years. NS-RCT was the most common untoward event. PFM crowns exhibited a higher rate of untoward events than complete metal crowns and a lower rate than all-ceramic crowns. Crowns placed on individuals 50 years of age and younger had higher rates of untoward events than those placed on individuals ages 51 years and older. CONCLUSIONS:The risk of endodontic treatment after the placement of crowns is low. This risk increases with the placement of all-ceramic or PFM crowns and as the age of the patient decreases.