Laboratory evaluations of a toothbrush with diamond-shaped filaments for stiffness and efficacy

The purpose of these studies was to evaluate four toothbrushes with a similar flat profile for stiffness and efficacy in removing artificial plaque deposits from interproximal areas, or depth of removal from broad tooth surfaces, and to relate these findings to bristle stiffness. The test toothbrush had 5-mil diameter, elongated diamond-shaped bristles (D). Three toothbrushes contained 5-mil (5), 6-mil (6), or 7-mil (7) diameter round bristles. Stiffness studies were performed using the ISO 8627 method. In the efficacy studies, toothbrushing was conducted with a vertical or horizontal brushing motion on simulated anterior or posterior teeth using a brushing weight of 250 g. The bristles were placed at a 90 degrees angle to the tooth surface, and brushing was performed for 15 seconds at two strokes per second with 50 mm strokes. Each of the toothbrush designs was tested 24 times. Interproximal access efficacy (IAE) was recorded as the maximum width of simulated plaque deposit removed. Depth of deposit removal (DDR) was determined using a color comparative scale, where 0 = no deposit change and 4 = maximum removal. The averages of wet and dry stiffness measurements were found to be 7 > D > 6 > 5; all values were in the range accepted as soft texture. The means for total IAE were ranked D > 5 > 6 > 7, and total DDR mean rankings were D > 7 > 6 > 5. For the round bristles, stiffness was inversely related to IAE and paralleled the DDR rankings. Using ANOVA, the D and 5-mil toothbrushes had significantly higher (p < 0.05) IAE means compared to the 6- or 7-mil products. The D toothbrush had significantly higher (p < 0.05) DDR means than the 5-mil product. The diamond-shaped bristles in these flat profile products resulted in improved depth of deposit removal compared to the same design with 5-mil round bristles.