Centering Ability of Three Rotary Nickel-titanium Instruments in Simulated Canals:A Comparative Study / 华中科技大学学报(医学版)

ABSTRACT

Objective To compare the centering ability of three rotary nickel-titanium instruments Reciproc,Protaper and WaveOne in resin-simulated curved root canals.Methods A total of 30 resin-simulated curved canals(curvature=30°)were di-vided into 3 groups(n=10 each)using the random number table.They were prepared with Reciproc(group R),Protaper(group P)and WaveOne(group W)respectively.Pre-and post-operative images were obtained by a digital camera at the fixed position, and superimposed through Photoshop.The center displacement between pre- and post-operative images were measured at 10 points beginning at 1 mm from the end point of the canal with the software Digimizer at a ratio of 1 to 1.The data were analyzed through one-way ANOVA and Student-Newman-Kuels at a significance level ofα=0.05.Results The central point was shifted laterally to the curve at 1,2,and 3 mm from the end point of the canal,while it shifted medially to the curve at 6,7,and 8 mm.The centering ability was better in groups R and W than in group P with significant differences noted(P <0.05).No sig-nificant difference was found in the centering ability between group R and group W.Also there were no significant differences in the centering ability at 4,5,9 and 10 mm among the three groups(P >0.05).Conclusion Reciproc and WaveOne have similar centering ability.They preform better in terms of centering location than Protaper,especially at the apex and the most curved part of the canal.