Abstract

Background: The combination of NiTi alloy with rotary instrument is a turning point in clinical endodontics that helps to keep the original shape of the canal, reduce the errors such as displacement of the root apex, perforation,... This study aimed to compare the enlargement, canal transportation and centering ratio of two nickel-titanium file systems, WaveOne Gold and Protaper Next. Materials and method: In this in vitro study, forty L-shaped root canals in resin blocks curvatures 400 were divided randomly into two equal groups. The root canals of one group were prepared using Protaper Next files, and the other using WaveOne Gold files. Pre-instrumentation and post-instrumentation imaging were taken for all teeth and stacked on top of each other. The enlargement, canal transportation and centering ratio were evaluated at 1 to 9 levels from the apex. Results: In the apical and middle thỉds, canals prepared with WaveOne Gold files had a greater extension than those prepared with Protaper Next files; in coronal third, the Protaper Next group had a greater extent than the WaveOne Gold group, but the difference was not statistically significant (p > 0.05). Root canal transportation and centering ratio were no significant difference between the groups (p > 0.05). Both of groups were less centered in the canal at levels in curvature of the canal. Conclusion: Both of WaveOne Gold and Protaper Next were same in centering ability.