Comparison of passive ultrasonic debridement between fluted and nonfluted instruments in root canals.

The purpose of this study was to determine if passive ultrasonic irrigation using finger spreaders was more effective than standard files in removing debris after root canal instrumentation. Eighty-five straight canals were instrumented and then passively ultrasonically irrigated with either fluted files or nonfluted finger spreaders for 3 minutes or 1 minute. Images of split canal lumens were imported into Adobe Photoshop CS2 (Adobe Systems, San Jose, CA), and percentage of debris remaining was calculated. Analysis of variance and Student Newman-Keuls post hoc tests (p<0.05) showed that when comparing the entire canal, 3 minutes of activation with a file had significantly less debris remaining than 1 minute of activation with a spreader. There was a trend for 1 minute of activation with a file to have less debris than either 3 minutes or 1 minute of activation with a spreader. When comparing apical, middle, or coronal thirds between groups, no significant differences were found. The use of a nonfluted spreader did not improve debris removal.