Analysis of apical deviation by type of system used to drive NRT® MANI rotary instruments

Abstract

Purpose: One of the major challenges encountered in treatment of curved canals is maintaining their original features. This study aimed to examine whether the type of system used with NRT® rotary instruments might influence the occurrence of deviation in the apical region.

Methods: Twenty simulated curved canals were divided into two experimental groups. In Group 1, canal preparation was performed with the pneumatic hand piece, using constant speed, but without torque control. In Group 2, an electric motor with constant speed and torque control was used. The simulated blocks were photographed before and after preparation using a platform to maintain the same position in both photographs. Images were manipulated in Adobe Photoshop® to evaluate deviation at 1 mm and 3 mm from the working length (WL). The t test was used for statistical analysis of data. The significance level was set at 1%.

Results and Conclusion: Group 2 (electric motor) had lower values for deviation at both locations analyzed (1 mm and 3 mm from the WL). In both groups, sites 3 mm from the WL had lower mean deviation than sites 1 mm from WL.