Dental tribology at the microscale

Dental wear caused by tooth care is a complex phenomenon that depends on the quality of the tooth material, the type of toothbrush and the brushing slurry. Tooth wear is commonly determined in abrasion experiments using a standardized toothbrush in contact with a radioactively labeled dentin sample (RDA method). The increase of radioactivity in the slurry is a direct and highly-sensitive indicator for wear. It is, however, detrimental that RDA provides an integral view of the tribological processes leaving microscopic issues undetected. Therefore, in this contribution the macroscopic system of brush versus tooth was reduced to a microtribological setup analyzing the contact between a single bristle (monofilament) and a tooth sample. This setup allowed to correlate friction and wear events to topography and structure of the tooth and will enable the evaluation of cleaning processes microscopically in the future. In addition, results of this work were related to the literature results of RDA experiments. ► Aim of this study was to analyze friction and wear on human enamel during cleaning. ► The system was successfully reduced to the contact of a toothbrush filament and enamel. ► The setup allows to correlate friction and wear effects with topography changes on enamel. ► The setup is able to provide information on abrasion properties of toothpastes. ► Friction and wear are induced by the trapping of toothpaste particles during sliding.