As far as I´m concerned there could be an issue regarding making oneself bleed, by using a toothbrush. Are there any other problems that may arise by brushing teeth with a toothbrush in Shabbes? ...
Are you allowed to mix a pinch of baking soda with water and rinse your mouth with it instead of using mouthwash? Also there are two way to mix it: place some baking soda on your finger/hand and ...
What, if any, modern-day hygiene products are prohibited "oils" on Yom Kippur? Are deodorants and perfumes in this category? What about medical ointments?