Influence of kinematics on the cyclic fatigue of ProTaper Gold and WaveOne Gold

[摘要] Introduction: The aim of the study is to assess the difference in the dynamic cyclic fatigue resistance of ProTaper Gold (PTG) and WaveOne Gold (WOG) files tested in clockwise and counterclockwise continuous rotation against two different reciprocal motions. Materials and Methods: A total of 200 files were tested at 300 rpm. These files were divided into four groups according to direction and type of motion: (A) clockwise continuous rotation, (B) counterclockwise continuous rotation, (C) reciprocal motion with 150° counterclockwise and then 30° clockwise motion, and (D) reciprocal motion with 150° clockwise and then 30° counterclockwise motion. The files were operated in a stainless steel artificial canal with a 60° angle of curvature and a 5-mm radius. A continuous, axial oscillating motion was applied at one cycle/s. The number of cycles to failure (NCF) was recorded. The data were analyzed using two-way analysis of variance. Results: No significant difference in NCF was found between Groups A and B or between Groups C and D in all rotary systems used (P 0.05). However, reciprocal motions exhibited higher cyclic fatigue resistance than continuous rotations (P < 0.05). Moreover, PTG showed higher cyclic fatigue resistance than WOG (P < 0.05). Conclusions: Reciprocal motions have increased cyclic fatigue resistance, but the direction of the motion had no effect on the fatigue life of the tested instruments. PTG files had higher resistance to cyclic fatigue than WOG files.

[学科分类] 口腔科学

[关键词] Cyclic fatigue;kinematics;ProTaper Gold;WaveOne Gold