Comparing the Cutting Efficiency of Three Ni-Ti Rotary Files in the Curved Root Canals THESIS

Abstract

The aim of the present study was to compare the cutting efficiency and shaping ability of three NiTi rotary instrumentation systems in curved root canals of molar teeth regarding their dentine cutting ability by measuring the dentine thickness before and following preparation as well as the change in the angle of canal curvature and transportation occurred. A total of sixty extracted human permanent mandibular molar teeth were used in this study. Access cavities were done then special measures were taken to ensure standardization and reproducibility of CBCT images.Samples were divided into three main groups according to the type of the instrument system used; Protaper Universal file system (group I), Revo-S file system (group II) and HyFlex CM file system (group III). Then each group was further subdivided into two subgroups (subgroup A and subgroup B) according to the angle of root canal curvature. The dentine removal, canal curvature and mesio-distal transportation were assessed by comparing the pre- and post-instrumentation measurements taken on CBCT images. Cutting efficiency assessment using CBCT images analysis: The dentine cutting ability was assessed on the axial section by subtracting the pre- and post- CBCT images measures of dentine thickness taken at three levels on the axial sections (3, 6 and 9 mm). Then data were collected and statistical analysis was performed. Change in canal curvature and canal transportation using CBCT images analysis: The change in canal curvature was assessed by comparing the pre- and post- CBCT images in the sagittal sections while measurements to assess Mesio-distal transportation were taken on the axial sections at the same three levels have been taken to assess cutting ability.