Most toothpastes contain tiny abrasive particles designed to wear down plaque, but some also chip away at the tooth’s enamel, a bit like pebbles eroding a river bed over years of friction. This computer simulation shows how abrasive particles (coloured balls) sometimes get trapped between toothbrush bristles (blue) and the tooth’s enamel surface (grey). Dragging the particles over the surface can gradually erode the enamel (brown lines). This 'brushing simulator' is being using to test toothpastes with differently-sized particles and toothbrush bristles with different shapes – saving some of the time and cost of laboratory tests. The goal is to find a balance between plaque-beating and enamel-friendly and ultimately to suggest different combinations of toothbrush and toothpaste for different mouths.
Written by John Ankers
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