Date of Award
Master of Science (MS)
The objective of this study was to determine factors affecting survival of teeth after nonsurgical root canal therapy (NSRCT) among enrollees of Wisconsin Medicaid during the years 2001-2009. Only permanent teeth with NSRCTs and that had permanent restorations within 60 days after treatment completion were included in the analysis. Patients with less than 60 days of insurance coverage after treatment completion were excluded. NSRCTs and untoward events (extraction) were identified based on Code on Dental Procedures and Nomenclature (CDT). Kaplan-Meier methods were used to plot the survival distribution for the overall cohort and subgroups by age, gender, race, tooth location, geographic area (urban vs. rural), and restoration type (crown vs. other). Univariate and multivariable Cox proportional hazards regression were used to model time from root canal restoration to extraction. The multiple regression model included all baseline covariates: age, gender, race, tooth location, geography, and restoration type. After applying the inclusion and exclusion criteria, 14,281 teeth among 11,788 patients were included in the final analysis. The overall 5-year survival rate was 88.67%. Survival rates were higher among younger individuals, males, anterior teeth, and when post-operative restoration was a crown as opposed to a filling. This study concludes that the success of primary endodontic therapy in a Medicaid population can be significantly improved by using post-operative crown restorations.