Tooth Survival Following Non-Surgical Root Canal Treatment in South Korean Adult Population: A 11-Year Follow-Up Study of a Historical Cohort

Objective: This study examined the survival rate of root canal treatment (RCT) and identified the factors affecting the survival/failure of RCT with respect to the patient’s demographic, socioeconomic and dental healthcare factors. Methods: The data of patients with RCT were analyzed using the 2002 patient data of the Korean National Health Insurance Service (KNHIS). The analysis included 1,193,666 patients, with 1,414,715 targeted teeth. Survival analysis was performed using the Kaplan-Meier method based on the occurrence of the untoward event. The proportional hazard of failure of RCT was measured using the Cox proportional hazard model and considering variables were gender, age, income, type of dental healthcare, number of visits for RCT, and type of teeth. Results: The 11-year cumulative survival rate for non-surgical RCT teeth was 88.37%. The Cox proportional hazard model showed significantly lower females (HR 0.704; CI 1.022-1.079) than males. The hazard ratio (HR) of over 65 years (HR 2.959; CI 2.864-3.058) was higher than that of other groups. In addition, the HR varied according to the income level (medical beneficiary was the highest) and the type of dental healthcare (tertiary hospital was the lowest). Conclusion: Performing RCT survival analysis using representative data revealed that the demographic and socioeconomic factors of the patients affect the failure of RCT. This study can serve as the basis for improving the survival trend in RCT and provide important implications in clinical decision-making in endodontics.