Is it permissible for a sick person to break the fast because of toothache?
Praise be to Allaah.
If the person who has toothache needs to break his fast, he may do so, because in this case he is one of the sick to whom Allah granted a concession allowing them not to fast.
And Allah is the Source of strength. May Allah send blessings and peace upon our Prophet Muhammad and his family and Companions. End quote.
Standing Committee for Academic Research and Issuing Fatwas
Fataawa al-Lajnah al-Daaâimah, vol. 2, 9/203
-- Islam QA