Reference: Fataawa Ramadhaan – Volume 2, Page 479, Fatwa No. 420
Question: If one causes blood to flow, such as having his molar tooth pulled out?
Response: There is no problem, because he did not have his tooth pulled out to cause blood flow, rather, because of pain. So therefore, he wished to have his tooth removed. Then it is the norm that blood will flow after having the tooth removed. However, it is very little blood and does not amount to cupping.