Date of Award

Spring 2017

Document Type


Degree Name

Master of Science (MS)



First Advisor

Bhagavatula, Pradeep

Second Advisor

Stover, Sheila

Third Advisor

Hashimoto, Lance


Introduction: The objective of this study was to determine if a correlation exists between the time to core or post and core (core/post) placement following non-surgical root canal therapy (NS RCT), the time to crown placement following core/post placement, and the incidence of an untoward event. Materials and Methods: Utilizing the Delta Dental of Wisconsin Insurance Database, information was analyzed from 476,479 initial NS RCT procedures. Of these teeth, 160,040 had a core/post and a crown placed before the end of the continuous coverage period or occurrence of an untoward event. Untoward events were defined as having a retreatment, apicoectomy, or extraction as defined by the Code on Dental Procedures and Nomenclature (1). Adjusted hazard ratios were calculated using a multivariable Cox proportional hazards model. Results: The survival rate from the time of crown placement to an untoward event was 99.1% at 1 year, 96.0% at 3 years, 92.3% at 5 years, and 83.8% at 10 years. Failure rates were greater when the core/post was placed more than 60 days following the NS RCT, as illustrated by the adjusted hazard ratio of 1.08, and when the crown was placed more than 60 days following core/post placement, as illustrated by the adjusted hazard ratio of 1.14. Overall, the survival rates of NS RCT were greater when performed by an Endodontist versus other providers. Conclusions: Along with other factors, such as provider type, this study shows that the long-term survival rates of initial endodontic therapy are significantly higher when the core/post is placed within 60 days following NS RCT and the crown is placed within 60 days following the core/post.