This study compared the effectiveness of three different types of electric toothbrushes, i.e., Interplak, Philips, and Rotadent, with a manual multitufted toothbrush (Blend-a-Med), in removing supragingival plaque and in preventing the development of gingivitis in adolescent patients with fixed orthodontic appliances. A single blind, cross-over, clinical trial was carried out in 36 adolescent patients, randomly divided into four equal groups. Every group tested each type of toothbrush, in a different sequence. Plaque and gingival scores were recorded at baseline and after 1 and 2 months of the test period. All patients received a professional prophylaxis after each clinical evaluation, except during the test period. The analysis of the data was performed with the nonparametric Friedman test. The results demonstrated, in essence, for all parameters that the manual toothbrush was the most effective. Of the three electric toothbrushes tested, the Philips toothbrush seemed to give slightly better results than the Interplak toothbrush, whereas Rotadent very clearly gave results inferior to all others. Personal preference on the four toothbrushes used revealed that the group as a whole least preferred a manual brush. However, the answers on the questionnaire did not always show a logical consistency. Therefore it should be interpreted with some caution.