Objective To study the deactivation of the endotoxin in artificial glass root canals with ultrasonic vibration. Methods 80 artificial glass root canals were randomly divided into 8 groups: Ultrasonic vibration of 5 minutes, 7 minutes, 10 minutes, ultrasonic vibration of 5 minutes together with 3% H2O2 solution, only 3% H2O2 solution, ultrasonic vibration of 5 minutes together with 5.25% NaClO solution, only 5.25% NaClO solution and the control. Standard endotoxin solution was introduced into each root canal. Different time′ s ultrasonic vibration was applied to different groups. After ultrasonic vibration, the endotoxin activity of each group was tested by kinetic turbidimetric limulus test. Result There were no significant differences among the groups of different time ultrasonic vibration and the control（P>0.05）. There was great statistical difference between each group with root canal rinse solution and the control（P
