A new in vitro method for testing the interproximal cleaning potential of toothbrushing

A new laboratory method was developed and used to evaluate the approximal penetration of different toothbrushing techniques. Before brushing, the approximal surfaces on teeth numbers 33 to 38 were covered by a colored coating. After brushing from both the buccal and lingual sides, the teeth were removed and the remaining coatings on the approximal surfaces were photographed and magnified, and their areas were determined by computerization. Two conventional toothbrushing techniques and two toothbrushing techniques specially designed to enhance interproximal access were used. It was found that considerable areas on the approximal surfaces were left untouched by the toothbrush bristles, regardless of the toothbrushing technique employed. The findings suggest that improvements in toothbrush design will be a more important contribution to the attainment of effective interproximal brushing than the development of new brushing techniques. This test method shares many similarities with in vivo conditions and seems also well suited for evaluating interproximal cleaning potential of new toothbrushes.