Comparison of ultrasonic to hand instruments in the removal of subgingival plaque.

The primary objective of this study was to compare the effectiveness of hand and ultrasonic instrumentation in removing subgingival plaque. Twenty-four teeth in five patients were randomly assigned to be scaled by hand instruments, scaled by ultrasonic instruments, or uninstrumented as a control The subgingival tooth surface was delineated by a groove, and the teeth were then extracted for periodontal reasons. The percentage of plaque area relative to the total surface area of the side of the tooth was computed. No significant difference was found between the two methods in removing subgingival plaque. Furthermore, neither method removed all of the plaque.