Objectives:The aim was to compare the shaping ability of WaveOne reciprocating files with or without glide path in simulated curved S-shaped root canals.Materials and Methods:Forty ISO #15, 0.02 taper, clear resin Endo Training Bloc-S blocks were studied. The simulated curved S-shaped canals were dyed using ink, preinstrumentation images were scanned, and resin blocks were prepared and divided into Group A: PathFile and WaveOne and Group B: WaveOne. All canals were postoperatively scanned. Pre- and postoperative images were superimposed and evaluated at 12 defined measuring points. The efficacy of the systems was compared based on the amount and direction of canal transportation, centering ability, amount of material removed, and presence of canal aberrations. Mann–Whitney U-test and independent t-test were used for statistical comparison.Results:Both systems produced transportation at all levels and straightened the curved S-shaped canals. No significant differences in the amount and direction of transportation and amount of material removed were observed between the groups at each level (P > 0.05). However, Group A had significantly greater centering ability at the coronal straight zone (P = 0.018) and apical curvature (P = 0.014) levels than did Group B. Moreover, Group B showed more canal aberrations than did Group A.Conclusion:Within the limitations of the present study, the creation of a glide path with the PathFile system improved the centering ability of the WaveOne reciprocating file in the apical and straight coronal portions of the simulated curved S-shaped root canals and reduced the incidence of canal aberrations.