Musannaf Ibn Abi Shayba 18:929

Abu Bakr narrated to us, he said: Abu Usamah narrated to us, from Ibn Jurayj, he said: Ibn Abi Mulaykah informed me, from his grandfather, that a person came to Abu Bakr, and a person had bitten him, so he pulled his hand away from him, and his front tooth fell out. Abu Bakr said: "You have lost a front tooth."