The effect of four preparation techniques on the amount of apically extruded debris

The amounts of root canal material extruded from extracted teeth using four instrumentation techniques were compared. Eighty extracted human mandibular premolars with single canals and root curvatures of 9 to 28 degrees were divided into four groups: 1, conventional filing technique; 2, cervical flaring technique; 3, ultrasonic technique; and 4, sonic technique. The teeth were opened for endodontic access and a #10 file passed 1 mm beyond the apex to ensure canal patency. All teeth were prepared 1-mm short of the apical foramen. Debris extruded in each case was collected and weighed after it was desiccated. The mean weights of extruded material for the groups were compared by analysis of variance. There was a statistically significant difference in debris extrusion between the conventional filing technique and the sonic technique. The groups ranked from lowest to highest in debris extrusion were as follows: 1, sonic technique; 2, cervical flaring technique; 3, ultrasonic technique; and 4, conventional technique.