Can dental treatment invalidate the fast? Is the fast broken by having dental treatment? Does receiving dental care interrupt the fast?

Fasting is not invalidated solely due to dental treatment. The injections made for painless treatment do not invalidate fasting because it is not considered as eating and drinking. However, if water, blood or substances used in treatment reach one’s stomach during the treatment while gargling mouth with water etc., then fasting is invalidated and qada is required.

Source: Presidency Of Religious Affairs The Turkey, High Board of Religious Affairs FATWAS

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