Laws of Tzom Gedaliah, 3rd of Tishrei 5782

Is it permitted to bathe on a fast day?

All fast days except Tisha B'Av are permitted for bathing, anointing, wearing leather shoes, and marital relations (Chazon Ovadia p. 21). There is no difference whether one bathes in hot or cold water, or immerses in a mikveh.

Is it permitted to brush teeth on a fast day?

It is permitted to rinse one's mouth on a fast day when filling the mouth with less than a revi'it of water, even with toothpaste. With more than a revi'it, it is not appropriate to do so (Chazon Ovadia p. 28).

Ach Tov VaChesed - Daily Halacha