Reference: Fataawa Ramadhaan – Volume 2, Page 479, Fatwa No. 421
Question: If one felt pain in his teeth and went to the dentist who either cleaned them or removed one of his teeth, does any of this have any effect on his fast?
If the dentist gave him an anaesthetic injection, does this affect the fast?
Response: None of that which is mentioned in the question has any affect on the validity of the fast, rather it is an exemption and he must be aware that this injection has no affect on his fast, [i.e] that it does not constitute what is understood as nutritional. Basically, his fast is correct and free from any defect.