Dragonborn
Scale cleaning and dental work. Different scaled dragonborn have to deal with dirt and things in-between scales can cause discomfort as well as hosts for parasites.For the teeth, probably to ensure there is no blockage or spills for their breath weapon.Annoyingly painful.Weaving would also be paramount since those same scales may end up snagging and cutting up human clothing.
Tritons
A water pick is It's a small water hose that shoots pressured water.Not strong enough to pierce flesh, but xan definitely get chunks out from between teeth.They could make a paste.I'd imagine it's mor using their inherent water magic to make a washing machine out of their mouth.