Technical quality of root canal preparation with novice operators - reciprocation compared with continuous rotary motion

Aim: The aim of this study was to compare the ability of two reciprocation motion file systems with a continuous rotary system for preparing simulated canals by undergraduate dental students. Methods: Following clinical demonstration and instructions, 84 undergraduate dental students prepared three endodontic training blocks; first using the continuous rotary motion file system (ProTaper Universal) then two reciprocation motion file systems (WaveOne and Reciproc), following manufacturers' instructions, in a crossover study design. Data on preparation time, user preference and procedural errors including ledges, apical zips, file separation, canal transportation and over-preparation were collected. All preparations were assessed using high magnification digital images by three observers. Data analysis was performed using logistic mixed modelling and odds ratios were calculated comparing the methods. Results: Both reciprocation systems exhibited fewer procedural errors than ProTaper Universal. The odds of an error occurring were significantly higher when using Reciproc compared with WaveOne. The odds ratio was 2.8, with a 95% confidence interval of 1.2 - 6.7 (P = 0.020). ProTaper Universal resulted in the highest incidence of ledges (22.6%), separations (10.7%) and transportations (14.3%). The Reciproc system resulted in the highest incidence of both apical zips (6.0%) and over-preparation (8.3%). No file separation occurred while using both reciprocating systems. Conclusions: Both reciprocation systems produced fewer procedural errors than the continuous rotary system. The results with WaveOne were favourable, with a low incidence of procedural errors, a higher student preference and the shortest preparation time. Parole chiave: outcome, procedural errors, ProTaper, Reciproc, reciprocation, WaveOne