Comparison of procedural errors resulting during root canal preparations completed by junior dental students in patients using an '8-step method' versus 'serial step-back technique'

Aim: To compare procedural errors occurring during preparation of root canals by junior dental students in patients using a new '8-step method' versus traditional 'serial step-back technique'. Methodology: Junior dental students treated 291 root canals of maxillary and mandibular teeth in patients. A new '8-step method' was used to prepare 149 canals, whilst the traditional 'serial step-back technique' was used for 142 root canals. Instrumentation was carried out in both techniques using standardized stainless steel K-files and coronal flaring with Gates-Glidden reamers. In the apical one-third, a filing motion was used in the traditional technique; with the '8-step method', reaming or filing motions were used in sizes up to 25 and only reaming in sizes larger than 25. All root canals were obturated with guttapercha points and AH26 using a lateral condensation technique. Pre- and postoperative radiographs were made of each tooth. Procedural errors were recorded and statistically analysed using a binomic test for comparison of proportion. Results: Significantly (P < 0.0001) more root canals maintained their original shape with no deviation (91%) with the '8-step method' compared to the traditional 'serial step-back technique' (61%). The procedural errors detected with the '8-step method' consisted of 10 canals with transportation (5%) and five with root perforations (2%); there were no canal obstructions. With the 'serial step-back technique', significantly (P < 0.0001) more errors occurred: 28 canals were transported (17%), 10 had root perforations (7%), and 16 canals were obstructed (6%). The differences in maintaining the original root canal shape between the two methods were significantly greater in molar versus anterior teeth. Conclusions: The new '8-step method' resulted in fewer procedural errors than the traditional 'serial step-back technique' when junior students prepared root canals in patients.