Can we brush our teeth using toothpaste during fasting?
It is Makruh to use either mouth wash or toothpaste while fasting as it endangers the fast. If mouthwash or toothpaste goes down the throat, the fast will invalidate.
Instead, you may use miswak during the fast, to keep your breath fresh and teeth clean. Just make sure that it is not an artificially flavoured miswak.
And Allah Ta’āla Knows Best
Mufti Faisal al-Mahmudi