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[The effects of three nickel-titanium rotary instruments on root canal curvature]
1Department of Endodontics, Faculty of Stomatology, Sun YatSen University of Medical Sciences, Guangzhou 510055, Guangdong province, China. xi-wei@21cn.com
Objective:
To investigate the effects of three nickel-titanium rotary instruments on root canal curvature and their working efficiency.
Methods:
64 curved mesial canals of extracted lower molars were randomly assigned to four groups: Flexofile, LightSpeed, ProFile, Qantec SC. Root canal preparation was carried out at two stages: first to size 30, then to size 40. The root canal curvatures before and after preparation as well as preparation time were measured.
Results:
Preparation with Flexofile resulted in the maximum reduction of root canal curvatures. The differences between three nickel titanium (Ni-Ti) groups and Flexofile were statistically significant from bucco-lingual view (P<0.01). No significant differences were detected between pre- and post-operative curvatures within Ni-Ti groups when preparation was carried out to size 30 (P>0.05). Preparation with ProFile or Quantec SC instruments cost significantly less time than the other two groups P<0.01).
Conclusion:
Preparation with Ni-Ti rotary instruments maintained the root canal curvature to a maximum extent. The techniques were also timesaving.