Objectives: To compare the cleansing efficacy of a representative "ten seconds" auto-cleaning device with that of uninstructed manual toothbrushing in a pilot study.
Materials and methods: Twenty periodontally healthy probands refrained from oral hygiene for 3 days. Baseline full-mouth plaque scores (Rustogi Modified Navy Plaque Index, RMNPI) were assessed. After randomization, probands cleaned their teeth either with the auto-cleaning test device according to the manufacturer's protocol or with a manual toothbrush. Plaque reduction was assessed by two aligned blinded investigators. After a 2-week recovery, the clinical investigation was repeated in a crossover design. The brushing pattern of the auto-cleaning device was analyzed in probands' casts.
Results: Full-mouth plaque reduction was 11.37 ± 3.70% for the auto-cleaning device and 31.39 ± 5.27% for manual toothbrushing (p < 0.0001). The investigation of the auto-cleaning device's brushing pattern in dental casts revealed a positive relationship of bristle rows in contact with tooth surfaces and the cleansing efficacy in the respective areas. A maximum of 2/4 bristle rows were in contact with the tooth surfaces; in some areas, the bristles had no contact to the teeth.
Conclusions: Uninstructed manual toothbrushing is superior to auto-cleaning. The alignment and density of the auto-cleaning device's bristle rows need to be improved, and assorted sizes would be necessary to cover different jaw shapes.
Clinical relevance: The auto-cleaning device has been developed to accommodate individuals with poor dexterity or compliance. To date, it is unable to provide sufficient plaque reduction due to an inappropriate bristle alignment and poor fit with diverse dental arches.
Keywords: Auto-cleaning; Biofilm(s); Electric; Oral hygiene; Plaque index.