In vitro evaluation of apical microleakage in retrofillings with different resection angles

Paraendodontic surgery is a procedure that aims to solve problems that could not be solved by, or when it is not possible to perform conventional endodontic treatment. The aim of this experimental study was to compare the apical microleakage of teeth sectioned at 45° or 90° to the long axis of the tooth and rootend filled with mineral trioxide aggregate (MTA) using stereomicroscopy. In this study, 26 maxillary central incisors were used. Cleaning and shaping were performed with use of the Oregon technique and the samples were randomly divided into two groups. In Group A (n=10) apical section was performed at an angle of 90°, making a retrocavity with an ultrasonic tip and retrofilling with MTA. In group B (n=10) the same procedures were performed, but the apical section was at a 45° angle. Then the samples were immersed in a dye (India ink), placed in an oven at 37° for 48 h before applying the clearing technique. Afterwards the teeth were assessed by stereomicroscope at 20x magnification to analyze dye leakage. Data were submitted to the Student'st test with significance level p<0.05. There was statistically significant difference between groups. Group B showed higher apical microleakage values compared with group A (P=0.004), but both groups showed dye leakage. The results showed that the 90° apical section promoted lower dye microleakage values at the dentinretrofilling material interface than the 45°section and could be considered the most effective technique for apical preparation in paraendodontic surgery.