It is narrated from Sayyiduna Imran bin Husayn (may Allah be pleased with him) that a man bit another man's hand, and the front tooth of the one who bit came out. He came to the Prophet (peace and blessings be upon him) and told him (peace and blessings be upon him), "and he (peace and blessings be upon him) declared it void."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 15622