ObjectiveTo compare the shaping ability of HyFlex, S3, K3XF and ProTaper in simulated resin canals.MethodsForty curved artificial root canals in resin blocks were divided into four groups randomly, and prepared to an apical using HyFlex, S3, K3XF and ProTaper, respectively. Images of pre- and post-instrumentation were superimposed by Photoshop CS5. Incidence of instrument fracture was recorded. The amount of resin removed by each system was measured at 10 measuring points by AutoCAD 2010. The data were analyzed by using one-way analysis of variance.ResultsOne case of instrument fracture occurred in S3, K3XF and ProTaper respectively. The centering ability of HyFlex was the best at 2 mm to 3 mm from the apex(PPConclusionThe four systems could maintain the original canal morphology well without obvious canal transportation and ledging. In the apical of the root canal, the shaping ability of HyFlex was the best compared with others, whereas K3XF seemed to have more advantages in the middle.
