Influence of operator’s experience on the shaping and centering ability of WaveOne single-file system

Aim. The aim of this study was to assess the influence of operator experience on the centering ability of WaveOne reciprocating system on S-shape simulated root canals. Methods. Forty S-shaped canals in resin blocks were assigned in two groups (n=20 for each group). Groups 1 was shaped by an expert operator, postgraduate in endodontics with more of ten years experience, while a not expert operator, a student in the last year of study, with poor endodontic experience performed shaping in Groups 2. A first survey of canals has been made with K-file 10 to assess the working length (WL), after that the glide path was achieved with PathFile 1, 2, and 3 (Dentsply Maillefer) at the WL. Subsequently, samples in groups 1 were shaped with ProTaper system (S1-S2-F1-F2), while group 2 was shaped with single WaveOne Primary reciprocating file in order to have in each method a tip size of 0.25 mm. Photographic method was used to record pre- and post-instrumentations images. After superimposition, it has been evaluated centering ability and total amount of resin removed between the two groups. Data have been analyzed using GraphPad Prism software 6.00 (GraphPad Prism Software, San Diego, CA,USA) by an expert in statistical analysis. Statistical significance between different groups was determined by oneway ANOVA and T test. Results. Centering ability was evaluated at each point (9 points in total) subtracting the amount of resin removed from the inner part to that removed from the outer aspect of the canal, while shaping ability was evaluated summing each others these parameters. Centering ability result to be different only at 4 and 5 millimeters from the apex, while shaping ability seems to be different between 4 and 6 millimeters from the apex. Conclusion. Shaping and centering abilities seems to be minimally conditioned by operator experience. Differences between the two groups were found only from 4 to 6 point levels, showing no differences at the apical levels.