Comparison of screw-in effect for several nickel-titanium rotary instruments in simulated resin root canal.
10.5395/JKACD.2010.35.4.267
- Author:
Jung Hong HA
1
;
Myoung Uk JIN
;
Young Kyung KIM
;
Sung Kyo KIM
Author Information
1. Department of Conservative Dentistry, School of Dentistry, Kyungpook National University, Daegu, Korea. skykim@knu.ac.kr
- Publication Type:Original Article
- Keywords:
Dynamometer;
Nickel-titanium rotary file;
Screw-in effect;
Simulated resin root canal
- MeSH:
Dental Pulp Cavity;
Root Canal Preparation
- From:Journal of Korean Academy of Conservative Dentistry
2010;35(4):267-272
- CountryRepublic of Korea
- Language:English
-
Abstract:
Screw-in effect is one of the unintended phenomena that occurs during the root canal preparation with nickel-titanium rotary files. The aim of this study was to compare the screw-in effect among various nickel-titanium rotary file systems. Six different nickel-titanium rotary instruments (ISO 20/.06 taper) were used: K3(TM) (SybronEndo, Glendora, CA, USA), Mtwo (VDW GmbH, Munchen, Germany), NRT with safe-tip and with active tip (Mani Inc., Shioya-gun, Japan), ProFile(R) (Dentsply-Maillefer, Ballaigues, Switzerland) and ProTaper(R) (Dentsply-Maillefer, Ballaigues, Switzerland). For ProTaper(R), S2 was selected because it has size 20. Root canal instrumentations were done in sixty simulated single-curved resin root canals with a rotational speed of 300 rpm and single pecking motion. A special device was designed to measure the force of screw-in effect. A dynamometer of the device recorded the screw-in force during simulated canal preparation and the recorded data was stored in a computer with designed software (LCV-USE-VS, Lorenz Messtechnik GmbH, Alfdorf, Germany). The data were subjected to one-way ANOVA and Tukey's multiple range test for post-hoc test. P value of less than 0.05 was regarded significant. ProTaper(R) produced significantly more screw-in effects than any other instruments in the study (p < 0.001). K3(TM) produced significantly more screw-in effects than Mtwo, and ProFile(R) (p < 0.001). There was no significant difference among Mtwo, NRT, and ProFile(R) (p > 0.05), and between NRT with active tip and NRT with safe one neither (p > 0.05). From the result of the present study, it was concluded, therefore, that there seems significant differences of screw-in effect among the tested nickel-titanium rotary instruments. The radial lands and rake angle of nickel-titanium rotary instrument might be the cause of the difference.
