Procedural Errors Associated With the Use of Rotary and Reciprocating Endodontic Instruments in Undergraduate Settings: A Scoping Review.

Introduction: Root canal treatment (RCT) performed by undergraduate dental students is associated with procedural errors that may compromise outcomes. With the increasing use of rotary nickel-titanium (Ni-Ti) instrumentation, understanding these errors has become important; however, existing evidence remains fragmented. This scoping review aimed to map the available evidence and summarize the reported prevalence of procedural errors associated with RCT using rotary and reciprocating instrumentation in undergraduate dental education. Methods: This scoping review followed the Arksey and O'Malley framework and PRISMA-ScR guidelines. A comprehensive search of MEDLINE via PubMed, Scopus, and the Cochrane Central Register of Controlled Trials (CENTRAL) was conducted for studies published between January 1993 and January 2025. Eligible studies included clinical and preclinical investigations involving undergraduate students using rotary or reciprocating Ni-Ti instrumentation and reporting procedural errors. Data were extracted and categorized into preoperative, operative, and post-operative errors, and prevalence was summarized descriptively. Results: A total of 878 records were identified, of which 24 studies met the inclusion criteria (14 clinical, 10 preclinical). Operative errors were the most frequently reported, particularly instrumentation-related errors such as instrument separation, ledge formation, and canal transportation. In clinical studies, instrument separation ranged from 0% to 5.1%, ledge formation from 0% to 29%, canal transportation from 0% to 21%, and perforation from 0% to 31.2%. Obturation-related errors, particularly underfilling and inadequate filling quality, were also common. In preclinical studies, instrumentation-related errors such as apical zipping, canal obstruction, and loss of working length were more frequently reported. Conclusions: Procedural errors remain prevalent in undergraduate endodontic practice despite the use of rotary and reciprocating instrumentation. Instrumentation-related errors were most consistently reported, while obturation-related errors were more prominent in clinical studies. The heterogeneity in study design highlights the need for standardized assessment criteria and improved training strategies.