Quantification of Plaque Removal Using a Brushing Simulator

Objectives: This study describes the development of methods that incorporate the combined use of plastic typodonts, simulated plaques and a mechanical brushing simulator to assess the effects of a variety of toothbrush/dentifrice regimens. The development of a custom model with which to cultivate saliva-derived biofilms on typodont surfaces is also described.
Methods: Plastic typodonts were coated with a layer of colored simulated plaque comprising powder indicator spray and brushed using a mechanical brushing simulator. Images were captured under controlled light conditions before and after brushing and color differences were measured using specialist software. This method was used to compare simulated plaque removal from occlusal surfaces before and after brushing and from interproximal areas after brushing with water or a 1450ppm fluoride toothpaste in a silica base (FTP) and a multi-level trim toothbrush. A custom drip-flow model was developed, using salivary inocula to cultivate oral biofilms on typodont surfaces to evaluate plaque removal by a new toothbrush in comparison to an old toothbrush with frayed bristles to simulate 3 months of use. Biofilms were stained and brushed with new or worn brushes to assess differences in biofilm removal.
Results: Image analysis of typodonts brushed under controlled conditions was able to significantly distinguish between brushed and unbrushed surfaces (p<0.05). Further, this method was able to distinguish between brushing with water or with FTP on the removal of simulated interproximal plaque, the latter causing significantly greater reductions (p<0.05). The custom-built drip-flow model was highly effective in cultivating oral biofilms on typodonts. These model biofilms were effective in demonstrating that new toothbrushes remove significantly more plaque from surfaces than brushes which had been worn by repeated brushing (p<0.05).
Conclusions: Laboratory-based models using simulated plaque or oral biofilms, in conjunction with a brushing simulator, were successfully able to quantify a variety of toothbrush/dentifrice regimens.