Analysis of the presence of filling material in oval root canals using computed microtomography after endodontic retreatment performed by different techniques

Abstract

Aim: The aim of this study was to evaluate the presence of filling material in oval root canals after endodontic retreatment performed by different techniques, considering the area (mm 2 ), location and root third using computed microtomography (μ-CT). Methods: Thirty human lower central incisor underwent biomechanical preparation, root filling and filling removal using two techniques (n=15): MN- manual retreatment technique (Gates Glidden burs and stainless steel manual files); and RT- rotary retreatment technique (ProTaper Universal and ProTaper Retreatment Systems). Cross-sectional images of the teeth were made using μ-CT to identify the presence of remaining filling in all root thirds of the canal walls. The remaining material detected in 150 μ-CT sections was identified and its area quantified (mm 2 ) for each root third individually. Results: Data analysis showed no difference in the remaining area of filling material (p=0.8611) for the both techniques. Higher frequency of remaining material was verified in the lingual wall of the root canals. Regardless of the retreatment technique, the apical third showed lager areas of remaining filling material. More areas of remaining material were detected in the cervical third of the RT group, whereas for the MN group, most areas were observed in the middle and apical thirds. Conclusion: According to our results, no significant differences were verified between the efficiency of the rotary and manual techniques for removing filling material due to the interferences caused by the root canal anatomy.