Sunan Ibn Majah, Chapter: The Chapters on Blood Money

(the sons of Ummayah): "We went out with the Messenger of Allah (saw) on the military expedition of Tabuk, and with us was a friend of ours. He fought with another man while we were on the road. The man bit the hand on his opponent, who pulled away his hand and the man's tooth fell out. He came to Messenger of Allah (saw) demanding compensatory money for his tooth, and the Messenger of Allah (saw) said: 'Would anyone of you go and bite his brother like a stallion, then come demanding compensatory money? There is no compensatory for this.'" Hence, The Messenger of Allah (saw) invalidated it (i.e compensatory in such case).