Abstract: Objective To evaluate the clinical effects of molars root canal preparation using Waveone.Methods The single file Waveone with crowndown technique was used to prepare 67 teeth and the stainless steel K files were used to prepare 54 teeth with the stepback technique.The lateral condensed technique was employed to fill the root.The root canal preparation time,instrument separation and root canal filling were compared.Results The successful rate of root canal filling in Waveone group was 91.1% and that of the control group was 66.7%.So the rate of Waveone was better than that of the control group(P＜0.01).The root canal preparation time of the group using Waveone was (17.76±1.96) mins and that of the control group was (33.82±2.37) mins.The time of Waveone group was shorter than that of the control group(P＜0.01).Conclusions Root canal preparation with Waveone shortens the time and has good shaping and obturating effects.

Key words: Waveone, root canal treatment, nickel-titanium instruments