ULTRASONIC ROOT-END PREPARATION - INFLUENCE OF CUTTING ANGLE ON THE APICAL SEAL

Apical resection is fundamental in obtaining a correct apical seal. Th e purpose of this study was to evaluate how the apical root resection angle and the cavity made by ultrasonic retrotips may influence the ap ical seal. A total of 48 extracted teeth were endodontically treated a nd sealed by gutta-percha vertical compaction: 24 were resected with a 45 degrees angle and 24 with a 90 degrees one, An ultrasound source ( P.M. 400 EMS) and a CT5 Scaler were used to make the retrograde cavity that was filled afterwards with ERA-zinc oxide-eugenol alumina-added cement. Apical leakage was determined using fuchsin and assessed after the roots were sectioned longitudinally. Linear dye penetration in de ntin and at the interface between dentin and cement was measured with a stereomicroscope (x12 magnification), and the results were statistic ally analyzed. Results showed that there was less infiltration both in dentin and in the space between the filling and the dentinal wall in the group with the 90 degrees angle, but this difference was statistic ally significant (p < 0.0001) only for the dentin, None of the samples showed leakage greater than the depth of the preparation. An apical c avity of 3 mm or more along the vertical axis can produce a safe and e ffective seal.