Evaluation of canal preparation with rotary and hand Niti files in curved root canals using Cone Beam Computed Tomography: An In Vitro Study

Background: Cleaning and shaping the root canal is an important phase in endodontic therapy. A prepared root canal should have a shape that flares from apical to coronal regions, maintaining the apical foramen and not changing the original canal curvature. Aim: To compare canal transportation, canal centring ability and remaining dentin thickness, in curved root canals using Twisted Files, PathFiles-ProTaper System, RaCe files, WaveOne reciprocating files and hand NiTi K-files with Cone Beam Computed Tomography. Materials and methods: 125 canals with completely formed apices and angle of curvatures ranging from 10 degrees to 60 degrees were used. The teeth were divided in five experimental groups of 25 each. Instrumentation was performed in Group I with Twisted files, Group II with PathFile-ProTaper, Group III with Hand NiTi files, Group IV with RaCe files and Group V with WaveOne reciprocating files. CBCT images were obtained before and after instrumentation with Kodak CS9300 equipment (CS3D Imaging Software 3.1.9). The amount of canal transportation, centering ability and remaining dentin thickness was calculated at nine levels. Results were analysed using ANOVA test and Post-hoc Bonferroni Multiple Comparison test. Results: Statistically significant difference was noted among the groups at the middle and apical third level with WaveOne files showing the least and hand NiTi files showing the highest transportation. The mean centering ratio was statistically highest with WaveOne and smallest with hand NiTi files at the middle third level. At the apical level (p < 0.05) the mean remaining dentin thickness was highest with WaveOne and smallest with PathFile-ProTaper. Conclusion: WaveOne and Twisted files were similar in terms of canal transportation, centring ability and remaining dentin thickness. Hand NiTi files and Pathfile-ProTaper systems produced maximum amount of canal aberrations.