Cyclic fatigue resistance of OneShape and WaveOne instruments using different angles of curvature.

This study compared the cyclic fatigue resistance of OneShape (OS) instrument which used continuous rotation with WaveOne (WO) instrument which used reciprocating motion. OS size 25, 0.06 taper and WO primary size 25, 0.08 taper were used in simulated canals with 45 degrees , 60 degrees , and 90 degrees angles of curvature until fracture. The number of cycles to fracture (NCF) was recorded to evaluate cyclic fatigue resistance. Data were statistically analyzed using two-way analysis of variance and Tukey's HSD test. Weibull analysis was performed on NCF data. WO had a significantly higher NCF than OS for all angles of curvature (p<0.05). According to Weibull distribution, WO instrument was predicted to have a higher number of cycles to survive than OS instrument. WO instrument which used the reciprocating motion had a greater resistance to cyclic fatigue than OS which used continuous rotation movement.