Commodore produced a library of cartridges for the Vic-20 and a great many of them were games. This cartridge is a rather unique game - perhaps Commodore, recognizing that a great may of its users were forsaking physical activity for gaming, decided that it could, at least, contribute to the well-being of its users by reminding them of the importance of brushing their teeth.
Probably not. In this game, the player controls a small figure with a toothbrush. The figure travels around the mouth of a large individual (whom we never see) and brushes away bits of plaque while avoiding various germ-like creatures that also inhabit the mouth.