Procedural errors in endodontic treatment: analysis of preclinical step-back preparation performed on training blocks

Introduction
Step-back technique is a basic method used for root canal preparation. In dental school curricula, this technique is taught in a preclinical environment, and it is regarded as safe and technically easy to perform, usually with low-risk of complications.

Objectives
The study aims to determine the incidence of different types of procedural errors during root canal preparation by second-year dental students using step-back technique performed on training blocks with 10% and 20% curvature.

Material and methods
Study material consisted of 160 endodontic training blocks, which were prepared manually by eighty second-year dental students using step-back technique. The blocks were assessed by two teachers who specialized in conservative dentistry and endodontics. The occurrence of the following errors was evaluated: working length loss, improper debridement, alteration of original root canal shape, apical over-instrumentation, instrument separation, root canal blockage with dentine chips, apical transportation or perforation in root canal wall, and ledge formation within root canal wall.

Results
Percentage of error-free blocks with 10% curvature was significantly higher than the percentage of error-free blocks with 20% curvature (34% and 4%, respectively). Improper debridement was the most frequently observed error in both groups (42% and 94%, respectively).

Conclusions
Our findings indicate a gap in the correct method of imparting knowledge to dental students regarding root canal preparation techniques. This disparity can be used constructively to create better training programs and more effective modules for dental students to minimize their margin of error.