Question: The dentist uses water to cool the teeth of the patient while bleaching them. Does the patient’s unintentional swallowing of this water affect Sawm (Fast)? Please taking into consideration that one can delay the treatment until night or even until after Ramadaan.
Answer: There is no harm in putting water in the mouth of a fasting person for the sake of treatment and other purposes, on the condition that one does not intentionally swallow it. If some of this water goes unwillingly into the patient’s throat, there is no blame on them. However, delaying the treatment until night or until after Ramadaan keeps one on the safe side... read more here.