I while fasting I develop a toothache, can i rinse my mouth with warm salt water to ease the pain?
As Salaam Alaikum.
In this case, you can rinse your mouth with warm salt water, but you must ensure that it does not go down the throat. If it goes down the throat, even mistakenly, your fast will be broken.
And Allah Knows Best.
Mufti Waseem Khan.