Influence of root canal curvature on the screw-in effect of nickel-titanium rotary files in simulated resin root canal.
10.5395/JKACD.2010.35.5.374
- Author:
Ji Young SON
1
;
Jung Hong HA
;
Young Kyung KIM
Author Information
1. Department of Conservative Dentistry, Kyungpook National University School of Dentistry, Daegu, Korea. wisekim@knu.ac.kr
- Publication Type:Original Article
- Keywords:
Canal curvature;
Dynamometer;
Nickel-titanium rotary file;
Screw-in effect;
Simulated resin root canal
- MeSH:
Dental Pulp Cavity;
Nickel;
Titanium
- From:Journal of Korean Academy of Conservative Dentistry
2010;35(5):374-379
- CountryRepublic of Korea
- Language:English
-
Abstract:
OBJECTIVES: Nickel-titanium (Ni-Ti) rotary instruments have some unexpected disadvantages including the tendency to screw-in to the canal. The purpose of this study was to evaluate the influence of root canal curvatures on the screw-in effect of Ni-Ti rotary files. MATERIALS AND METHODS: A total of 80 simulated root canals in clear resin blocks were used in the study. Canals with curvature of 0, 10, 20 and 30 degrees were instrumented with ProTaper instruments SX, S1, S2 and a ProFile of #25/0.06 to 1.0-2.0 mm beyond the initial point of root curvature. The screw-in force was measured with a specially designed device while canal was instrumented with a ProFile of #30/0.06 at a constant speed of 300 rpm. The data were subjected to one-way ANOVA and Scheffe multiple range test for post-hoc test. RESULTS: Larger degree of canal curvature generated significantly lesser screw-in forces in all groups (p < 0.001). CONCLUSIONS: More attention needs to be paid when using rotary instruments in canals with less curvature than canals with more curvatures to prevent or reduce any accidental overinstrumentation.
