A blind, two-way crossover clinical trial was carried out to compare the effectiveness of plaque removal between an electric toothbrush (Interplak) and a conventional manual toothbrush (Butler 311). Twenty adult patients having completed all active periodontal therapy and currently on periodontal maintenance program participated in the study. Each toothbrush was used for a period of 2 weeks by all subjects. The mean differences between baseline plaque scores and after the subjects used the brushes were analyzed by the paired t-test. The results indicated no difference in plaque removal between the Interplak and the control brush with the exception of the distal surfaces of the maxillary teeth.