Evolution of wear on enamel caused by tooth brushing with abrasive toothpaste slurries

Abstract

Maintaining good oral hygiene is vital to a healthy body and aesthetically attractive smile. Regular tooth brushing prevents cavities, tooth decay and gum disease which if left, can lead to serious health problems. However, cleaning your teeth comes with a drawback. Toothpastes contain abrasive particles, which in combination with the toothbrush, have the potential to wear tooth enamel. To optimise the cleaning efficiency of teeth and minimise the enamel wear it is essential to understand the science behind the tooth/toothpaste/toothbrush interface. An integrated approach is employed in this study to investigate the tribology of brushing, examining the friction and wear evolution. A reciprocating tribometer was modified to enable a toothbrush head to reciprocate against a bovine enamel disk to simulate the tooth brushing action, with a constant feed of either an abrasive free or a silica or alumina containing toothpaste slurry to the contact. The evolution of the friction with time during the brushing simulation as well as the changes in the enamel surface roughness were determined. The alumina slurry resulted in higher friction, increased wear depth and an increased roughening of the enamel surface compared to the silica slurries, with all abrasives causing 2 body grooving to the enamel surface. The spherical silica provided both the lowest friction and material loss of the slurries tested. The abrasive free slurry caused no wear or surface roughening but exhibited the highest friction during brushing.