The purpose of this study was to compare the subgingival and interproximal plaque removal of a manual toothbrush to that of an oscillating counter-rotational electric toothbrush. ninety teeth were divided into control, manual, and electric groups and test teeth received a total of 20 seconds of brushing. The teeth were then anesthetized, extracted, stained, dried, and examined with a computer-assisted video analysis system. The control group had 13.88% plaque-free interproximal surfaces, compared to 30.57% for the manual group and 53.23% for the electric group. The mean subgingival plaque-free measurement w as 0.05 mm for the control group, 0.64 mm for the manual group, and 1.36 mm for the electric group. The differences between the means were statistically significant for both measurements.