An in-vitro evaluation of remaining dentin thickness inconservative access cavity preparation usingdifferent endodontic access cavity burs- a cone beamcomputed tomographic study

The aim of this study was to evaluate the remaining dentin thickness(RDT) after conservative access preparation using traditional endodontic access cavity bur (Dentsply Maillefer, Ballaigues, Switzerland), endoguide precision micro endodontic bur(SS White) endodontic access bur 248 (Shofu) using cone beam computed tomography. For the present study thirty freshly human sound mandibular molars extracted due to periodontal reason were included. Depending on the type of bur used the conservative preparation was done and teeth were divided into three groups (n=10). Group 1 cavity prepared using traditional endodontic access cavity bur, Group 2 cavity prepared using endoguide precision micro endodontic bur(CK Burs) and Group 3 cavity prepared using endodontic access bur 248(shofu). Cone beam computed tomography (CBCT) images of the teeth were obtained. Conservative access cavity preparation was done using Dental Operating Microscope (DOM×13) magnification. Following access cavity preparation another CBCT scan was taken and RDT was calculated as the shortest distance from the outline of the root canal to the closest adjacent root surface, which was measured in facial, lingual, mesial, and distal surfaces for all the groups. Result: The statistical analysis was performed using ANOVA. Group 1and Group 3 showed increased removal of pericervical dentin whereas Group 2 showed decreased removal of pericervical dentin. Tukey’s pairwise comparison test was performed. A significant difference was observed between conservative preparation using endoguide precision micro endodontic bur, traditional endodontic access bur and endodontic access bur 248(P< 0.05). No significant difference was observed between conservative preparation using traditional endodontic access bur and endodontic access bur 248 (P<0.05). Interpretation and Conclusion: RDT in molars was significantly conserved using endoguide precision micro endodontic bur (CK Burs). Whereas, excessive removal of crown structure which includes percervical dentin and soffit occured using traditional endodontic access bur and endodontic access bur 248 was observed. Pericervical dentin and soffit preservation plays a very important role during access cavity preparation. Hence, endoguide precision micro endodontic burs(CK Burs)proved to have the ability to conserve the pericervical dentin.