The Comparison of two systems of Joy Taper and Bio Race in Transportation and preservation oc central position of curved canals (An invitro Study)

Objective :One of the important measure of proper root canal preparation is Maintaining the original position of the root canal.so ;instrument that result in Minimal change of canal position ,result in better cleaning and shaping . the aim of This study was to comparison of effect of Joy Taper and Bio Race on maintaining of Canal centering ability and transportation by CBCT in mesio buccal canals of human Extracted mandibular first molars in dental branch of Islamic Azad University of Tehran in2017-2018 METHOD AND MATERIAL: In this experimental study a total of 30 of mesiobuccal Root canals of human mandibular first molars with curvature ranging between 20-40 were randomly divided by Schneider and in two groups of 15 canals each , and Two In control Group and were imbedded in a puty imperession material and Submitted To CBCT. Group A was prepared with Joy Taper and group B was Prepared with Bio Race .According to manufactures protocol .pre and post Instrument image was Recorded .Image Were reconstruction and cross sections Corresponding to distance 1,3,7 mm from The anatomic apex were selected for Analysis by Gambill. Statistical analysis was performed With T-test and Repeated Measure ANOVA . RESULT: There was no significant different between the two groups of Joy Taper And Bio Race systems in maintaining the canal centralization P=0.930 and canal Transportation P=0.190, but significantly only in the 7mm control of the Bio Race system,it Was better in centering ability P=0.048  , also in each group at different sections of coronal , Mid and apical there was no significant difference . CONCLUSION:Our findings showed that Joy Taper and Bio Race having the same Result in transportation and centring ability.