A new method for in vitro evaluation of the interproximal penetration of manual toothbrushes.

A new in vitro method for determining interproximal penetration of different toothbrush designs is reported. This method is based on videotape recordings of the brushing patterns of 31 subjects. Circular, up-and-down, and back-and-forth brush strokes were all employed, with the brush being set at both 45 degrees and 90 degrees angles for back-and-forth brushing. Overall results were weighted according to the proportion of brushing time during which participants typically use each stroke. The tooth morphology was closely simulated by the use of typodonts. Interproximal penetration was measured by removal of "artificial plaque" (an ethyl ester of PVM/MA copolymer) shown to have a tenacity on the typodont tooth surface similar to 12-hour plaque as measured on 6 subjects. The brushing force used was based on the measured brushing force of 8 panelists during actual brushing and was consistent with forces reported in the literature. This method was used to test the interproximal penetration of three different toothbrush designs: rippled pattern (Crest Complete), multi-level (Colgate Precision), and flat-tufted (Oral-B P40). The Crest Complete was found to provide superior interproximal penetration to Oral-B P40 and Colgate Precision for all brushing techniques, although its advantage over the Colgate Precision failed to reach statistical significance for back-and-forth brushing with the brush at a 45 degree angle to the tooth. The Colgate Precision was superior to the Oral-B overall, and for three of four brushing techniques tested. There was no difference between the two brushes on back-and-forth brushing at a 90 degree angle.(ABSTRACT TRUNCATED AT 250 WORDS)