Objective: To evaluate the effects of ultrasound and sonic toothbrushes on the oral hygiene status of healthy people. Methods: This study was administered with a randomized, controlled, and double-blind trial. Twenty-nine firstyear dental hygiene students answered a questionnaire on oral hygiene behavior, and they were divided into one of four groups after pre-examination. Each group used an electronic toothbrush with different modes (2 times/day, 3 min) after tooth brushing instruction (TBI)

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... r four weeks; A (control): used with power off; B: used with the sonic mode (sonic wave: 16,000 strokes/min); C: used with the ultrasound mode (ultrasound frequency: 1.6 MHz); D: used with the ultrasound + sonic mode. The plaque index (PlI) and gingival index (GI) were assessed. The unstimulated saliva flow rate was measured (spitting method, 1 min). The Ethical Committee of the Japan Dental Hygienists' Association approved this study's protocol (vote number: 2). A Wilcoxon signed-rank test was used. Results: The PlI decreased in group C (baseline: 1.42 ± 0.83; 4 weeks: 0.92 ± 0.34; p<0.05) and D (baseline: 1.41 ± 0.3; 4 weeks: 0.92 ± 0.3; p<0.01). The unstimulated saliva flow rate of group C and D, which used electronic toothbrushes with ultrasound, increased significantly (baseline: 0.57 ± 0.33 mg; 4 weeks: 0.78 ± 0.5 mg; p<0.05). The GI did not change in all groups. Participants who had received TBI before this study had an increased unstimulated saliva flow rate (baseline: 0.65 ± 0.35 mg; 4 weeks: 0.87 ± 0.5 mg; p<0.05). Conclusion: The use of electronic toothbrushes with ultrasound for four weeks effectively decreased the PlI and increased the unstimulated saliva flow rate. Professional prophylaxis was required to improve gingival status. TBI enabled participants to use electronic toothbrushes more effectively to stimulate the salivary gland and to increase the unstimulated saliva flow rate.