The relative cleaning effectiveness of manual and powered toothbrushes

Recently, a number of new low-cost powered toothbrushes have been marketed globally. Assessment of their cleaning capability in vitro is now becoming manageable with novel configurations of new brushing machines, which allow for the conventional brushing action and added device action. In this study, the in vitro stain removal efficiency of two marketed powered toothbrushes (Crest SpinBrush and Dr. Best Battery), a new prototype (Crest SpinBrush Pro) and two manual toothbrushes (Oral-B Indicator Soft and Oral-B CrossAction) was evaluated using a different brushing technique as a modification of the laboratory testing method developed by Stookey and associates at Indiana University Oral Health Research Institute. This was a randomized, parallel-group design study that examined stain removal with a novel toothbrushing configuration adapted for powered and manual toothbrushes. Stain was scored before and after brushing for two consecutive one-minute periods using digital image analysis. The mean change in L* was statistically compared among toothbrushes with analysis of covariance. The mean baseline stain scores ranged from 36.3-40.2 for the five toothbrush treatment groups. There was statistically significant evidence of imbalance with respect to baseline mean L* (p = 0.006), ranging from 36.3 for the CrossAction brush to 40.2 for the Crest SpinBrush Pro. Baseline stain imbalance was addressed with the ANCOVA statistical model which adjusts for baseline L*, effectively comparing all treatments at the same baseline stain level. Baseline L* was not statistically significant (p > 0.1) in the ANCOVA model at one or two minutes. With respect to all surfaces examined, the new prototype powered toothbrush (Crest SpinBrush Pro) delivered an adjusted (via analysis of covariance) mean L* reduction of 14.4 and 22.0 at the end of the first and second brushing periods, respectively, while the four remaining toothbrushes delivered adjusted mean L* reductions ranging from 5.6-8.6 and 9.4-13.3 at the end of the first and second brushing periods, respectively. These results represent 67-157% for the first brushing period, and 65-134% for the second brushing period greater stain removal for the new prototype powered toothbrush. Overall, the new prototype powered toothbrush had statistically significantly greater stain removal (p < 0.001) than all other toothbrushes tested. The results, using this powered toothbrush-compatible brushing machine configuration, show that the new prototype powered toothbrush (Crest SpinBrush Pro) produced statistically significantly enhanced stain removal efficiency relative to the four other toothbrushes, including Crest SpinBrush and Dr. Best powered toothbrushes. The newly configured brushing machine delivered a robust method for separating statistically significant in vitro differences for the complex cleaning action of powered toothbrushes.