Laboratory interproximal access efficacy comparison of bi-level and flat bristled toothbrushes.

A laboratory method for testing interproximal access efficacy (IAE) differentiates between different toothbrush designs and has been correlated with clinical plaque removal efficacy. The purpose of this study was to compare the bi-level trim Advanced Design Research (ADR) toothbrush with two flat-trim toothbrushes, Oral-B 40 (OB) and Colgate Plus Full Size (CPFS) toothbrushes, all in soft texture, for IAE using this laboratory method. Vertical and horizontal motions were used on simulated anterior and posterior tooth shapes at 250, 500, and 750 g brushing weights. Brushing times were 60 seconds. IAE is a measurement of the maximum width of the brushing stroke around the simulated teeth. Sixteen brushes of each design were tested for each parameter monitored. For both brushing motions and tooth shapes tested, at the 250 g brushing weight, ADR had significantly higher IAE (p < 0.01 by ANOVA) compared to OB and CPFS. The IAE values at 500 g for ADR were consistently higher than the other two brushes, while not always significantly different. At 750 g the three brushes approximated each other on IAE and were equally effective. When total IAE (means of all weights tested) were evaluated, the ADR was superior (p < 0.05 by the Student's t-test) to the OB and CPFS products. In this laboratory study, the Advanced Design Research toothbrush had consistently and significantly higher interproximal access efficacy compared to the Oral-B and Colgate Plus toothbrushes. These results were predictive of a recent clinical plaque removal study.