Comparison of the cleaning efficacy of passive sonic activation and passive ultrasonic activation after hand instrumentation in molar root canals

The purpose of this study was to compare the cleaning efficacy of passive ultrasonic activation with that of passive sonic activation after hand instrumentation. Sixty curved molar canals were hand-instrumented to size 35 and divided into three groups. Group 1 received no further treat-ment. Group 2 received 3 rain of passive sonic activation. Group 3 received 3 rain of passive ultra-sonic activation. The roots were split and photomi-crographs (×20) were made of the apical 6 mm of canal. A transparent grid was placed over pro-jected images, and the total number of squares covering the apical 6 mm of canal space and the number of squares containing debris were counted. A debris score was calculated for eac