Comparison of Canal Transportation, Centering Ratio by Cone-beam Computed Tomography after Preparation with Different File Systems.

AIM One Shape Apical 1 (OSA 1) is a new file for preparing the apical aspect of the root canal after One Shape (OS, Micro Mega, Besançon, France). This study compared apical transportation and centering ratios in curved root canals, which were instrumented with ProTaper Next (PTN, Dentsply Tulsa Dental Specialties, Tulsa, OK) up to size X3 and with OS up to OSA 1. MATERIALS AND METHODS Forty-eight mesial canals of mandibular molars were assigned into two groups (n = 24) with respect to canal length and curvature. Root canals were accessed conventionally and preperation was completed with PTN files up to X3 or with OS up to OSA 1 according to the manufacturer's protocols. Apical transportation was assessed pre- and postinstrumentation using cone-beam computed tomographic (CBCT) scans of 1, 2, 3, 4, and 5 mm sections. A Friedman test was performed to assess the significance between file systems. RESULTS No significant difference was found between the file systems regarding apical transportation and centering ratio values (p > 0.05). Transportation in the mesial direction was greater than the distal transportation for both file systems. CONCLUSION Considering apical transportation and centering ratio in curved canals, two systems provided similar results. CLINICAL SIGNIFICANCE Preparation up to One Shape Apical 1 or ProTaper Next X3 was shown similar results regarding apical transportation and centering ratio. Both systems were safe to use in curved molar root canals.