Cyclic Fatigue Resistance of 2-Shape Endodontic System

Abstract

Aims: This study aimed to evaluate the effect of different tapers (4% and 6%) on the cyclic fatigue resistance of the 2Shape endodontic system using three types of canal curvature 45°,60°, and 90°. Materials and Methods: This research used Sixty (60) NiTi rotary files. Two sets of these files were created. (n = 30 for each group), group one TS1 (0.25) taper 4%, group two TS2 (0.25) taper 6%. Then, each group was subdivided into three subgroups (n = 10 for each subgroup) each subgroup was tested in 45°, 60° and 90° canal curvature respectively in a stainless-steel metal block containing an artificial canal with a radius of curvature of 3mm and diameter of 1.5 mm. Each file was rotated continuously at 300 rpm and 1.2 N.cm torque for TS1, 300 rpm, and 2.5 N.cm for TS2 until it fractured. The time it took to separate the files was noted. Each file's number of cycles to failure (NCF) was computed. Kolmogorov-Smirnova normality test was done for all instruments and One-way ANOVA was used to examine the data statistically. Results: At 45º canal curvature there is a highly significant difference between 2Shape taper 4% and 2Shape taper 6% (p ≤ 0.01). Regarding canal curvature of 60º there is a highly significant difference between 2Shape taper 4% and 2Shape taper 6% (p ≤ 0.01). For canal curvature of 90 º there is a highly significant difference between 2Shape taper 4% and 2Shape taper 6% (p ≤ 0.01). Conclusions: This study concluded that the 2Shape system resists cyclic fatigue better at canal curvature of 45° followed by 60° and 90°. Regarding the taper used 4% is better than 6%. To limit the possibility of separation, it is advised that these files be used just once.

Keywords

• cyclic fatigue
• ؛2shape system
• ؛ts1