A Scoping Review of 4 Decades of Outcomes in Nonsurgical Root Canal Treatment, Nonsurgical Retreatment, and Apexification Studies-Part 1: Process and General Results.

Introduction: Despite initiatives to standardize reports, variances in study design, outcomes assessed, and tools used are persistent in the literature. This review scoped the existing literature on endodontic outcome studies for future development of core outcome sets.

Methods: A comprehensive literature search of randomized controlled trials, cohort studies, case-control studies, and case series (≥10 patients) published after 1980 including patients ≥10 years of age with any preoperative pulpal and periapical diagnosis in permanent teeth requiring nonsurgical root canal treatment (NS-RCT), retreatment (NS-ReTx), or apexification was performed. Abstracted data were reported through descriptive statistics.

Results: Of the 9957 studies screened, 354 were included. An increase in the quantity of endodontic outcome publications and levels of evidence in their study design was noted over the past 4 decades. Although 41% of the studies included participants 26-50 years of age, literature including participants >50 years old has increased since 2000. Apexification and NS-ReTx were mostly provided by specialists and postgraduate students. The most common follow-up period was 2-5 years (35%), and most randomized controlled trials (58%) reported follow-up times <1 year. Multiple-visit treatment was most common in apexification studies (85%). Deficiency, inconsistency, and ambiguity were observed across many reports.

Conclusions: NS-ReTx and NS-RCT/NS-ReTx studies have increased over the past 2 decades, particularly those focusing on molars and patients >50 years old. Despite the progress in endodontic research, heterogeneity in reporting styles yields considerable limitations, particularly data standardization challenges and inconsistencies in methods and results reporting. This scoping review highlighted the state of available research and supported the development of standardized guidelines for future investigations.