RESUMEN
Introduction and Objective:To analyze the time required to dissolute the pulp tissue under different methods of sodium hypochlorite activation. Material and methods: 30 bovine pulp fragments, with an approximate volume of 45 ± 5 mg were divided into three experimental groups (n = 10). In group 1, only the fragments were immersed in 15 ml of 2.5% sodium hypochlorite. In group 2, the irrigant was manually stirred with an endodontic instrument type K size 40. In group 3, we used the ultrasonic insert n.39, driven by ultrasound device Jet Sonic Total. The time required for total dissolution of bovine tissue was measured and recorded for statistical analysis. Results and Conclusion: According to analysis of variance (Anova), with p<0.05, Group 1 showed significantly higher dissolution time than Groups 2 and 3. Moreover, no difference between the use of ultrasound and manual activation of the irrigating solution was found.