Tooth whitening through the removal of extrinsic stain with a power toothbrush: results of four randomized, examiner blind, positive controlled clinical studies.

PURPOSE: To assess the "whitening" through stain removal benefit delivered by a prototype power toothbrush and a positive control power toothbrush over a 2-week period. METHODS: Four independent studies with identical protocols were conducted to examine tooth whitening through the removal of extrinsic stain with power toothbrushes. These were randomized, positive-controlled, two treatment, parallel group, examiner-blind, 2-week studies involving approximately 20 healthy adults with longstanding visible extrinsic stain on the facial surfaces of the 12 anterior teeth. Approximately 10 subjects per group were enrolled into the study for each of the two treatment groups; a prototype-powered toothbrush group (Crest SpinBrush Pro Whitening) and a positive control powered toothbrush group (Sonicare Personal 4100). RESULTS: In these four studies, the positive control sonic power toothbrush statistically significantly (P < 0.05) reduced stain scores by 84%, 77%, 44% and 49% following 2 weeks of brushing. Importantly, the prototype whitening power toothbrush statistically significantly (P < 0.05) reduced stain scores by 88%, 65%, 59% and 57% following 2 weeks of brushing. In both the individual studies and a combined analysis involving all four studies, the adjusted mean changes between treatment groups did not differ significantly between the two treatment groups. In the combined analysis, a one-sided upper 95% confidence bound on the difference in stain reduction scores between the two toothbrushes (positive control minus prototype) was found to be 8.3% of the prototype toothbrush adjusted mean change. This supports that the prototype power toothbrush removed extrinsic stain at least as well as the positive control toothbrush across these four studies.