Ability Of Three Kinds Of Rotary Ni-Ti Instruments To Model Moderately Curved Root Canal

Objective: To compare the effects on forming ability of moderately curved root canal between Protaper next,Waveone and Twisted File Adaptive(TFA)three ki-nds of rotary Ni-Ti instruments.Methods: Eighty moderately curved(20 degrees)plastic root canals were randomized into four groups,namely,TFA group(group T),Waveone group(group W),Protaper next group(group P)and st-ainless steel K protaper group(group K),20 root canals in each.TFA protaper,W-aveone protaper,Protaper next and stainless steel K protaper were respectively use-d for root canal preparation.Changes of root canal curvature and deviation of roo-t tip were recor ded.The axis center rate was recorded,time of root canal preparat-ion was statisti cally analyzed,and the length of root canal work after preparation was determined.Results:(1)The time of root canal preparation in group W was t-he shortest,fol lowed by group T,and group K was the lowest(P<0.05);(2)For distance from t eeth root to cusp 3,5,7 mm section,the offset of group T was t-he minimum(P<0.05),followed by group W,and the offset of group K was the maximum(P<0.05).The axial center rate of group T was the highest,followed by group W and group P group,and group K was the lowest(P<0.05);(3)Befor-e preparation,t here was no significant difference in bending degree between groups(P>0.05).Aft er preparation,the bending degrees in all groups were reduced,and the decrease of bending degree in group K was the most obvious while in group T was the mini mum.Conclusion: The forming ability of TFA rotary Ni-Ti instr-ument to moderat ely curved root canal is good,with high elasticity,high toughness,high c-enter loc ation ability,and little deviation.