Evaluation of the impact of toothbrush wear on artificial plaque removal efficacy

This study evaluated the artificial plaque removal efficacy and wear patterns of three high-density, ultrasoft toothbrushes with polyester filaments (standard, small, and large head sizes) after simulated long-term use. A 3D-printed jaw model and artificial teeth were used, and brushing tests corresponding to 3 months (3 M) and 6 months (6 M) of use were performed. The wear index (WI) was calculated, and morphological changes of the filament tips were examined using a digital microscope. The artificial plaque retention rate was then measured for new brushes (Control), 3 M, and 6 M specimens. In the small-head toothbrush, the artificial plaque retention rate significantly increased after 6 M compared with the control and 3 M. In contrast, no significant differences were observed across usage periods in the standard- and large-head toothbrushes. The WI increased over time in all toothbrushes, with significantly higher values at 3 M and 6 M in the small-head group. Flattening of the filament tips was observed with increasing simulated use. These findings suggest that high-density toothbrushes with an appropriate head size can maintain artificial plaque removal efficacy for up to 3 months, whereas head size influences cleaning performance and wear characteristics after prolonged use.