Influence of access cavity design on root canal instrumentation efficacy in molars – An in vitro study

Abstract Background: Several designs of access cavity have been evolved in the recent past with the concept of minimal tooth tissue removal which would improve the root canal treated teeth fracture resistance. Aim: To investigate the effect of conservative design access cavity during the instrumentation of maxillary molar root canals. Materials and Methods: Eighty noncarious maxillary molars were assigned to the traditional and conservative access groups ( n = 40 each). After designated access preparations, the teeth were immersed in Lugols’s solution for staining the pulp tissue. Root canal instrumentation was performed with TruNatomy file system. Pre- and postinstrumentation nano-computed tomography (CT) images were taken and reconstructed using CT-An software. Root canals volumetric analysis was done with CT-Vol software. The analysis of the data was dealt with Shapiro–Wilk test and independent t -test. Results: The volume of pulp canal space before and after instrumentation changed significantly between the traditional and conservative access design groups, according to an independent t -test. In comparison, the mean volume of dentin removed was much larger in the TAC group ( P = 0.0016). The independent t -test manifests difference significantly between traditional endodontic access cavity (TAC) and conservative access cavity (CAC) with percentage of unprepared canal walls. The mean percentage of unprepared area was significantly lesser in TAC group as compared to CAC group ( P = 0.0022). Conclusion: The volume of dentin removed was greater in TAC than with the CAC design. The amount of untouched canal wall area was significantly higher in conservative access design than with the traditional access design group.