The beloved Rasûl of Allah śallAllāhu álayhi wa sallam said,

When you stand at night to offer Salâh, you should clean your teeth with a Miswāk because when you recite the Qur’ân an angel places his mouth on yours and anything coming out of your mouth enters the mouth of that angel. [Shu’ab al-Îmân, vol. 2, pp. 381, Ĥadīth 2117]