سنن أبي داود

Narrated Anas bin Malik: Al-Rubayyi', sister of Anas b. al-Nadr, broke (one of) the front teeth of a woman. They came to the Prophet (ﷺ). He made a decision in accordance with the Book of Allah that retaliation should be taken. Anas b. al-Nadr said: I swear by Him who has sent you the truth, her front tooth will not be broken today. He replied: Anas ! Allah's decree is retaliation. But the people were agreeable to accepting a fine, so the Prophet (ﷺ) said: Among Allah's servants there are those who, if they adjured Allah, He (Allah) would consent to it.

Abu Dawud said: I heard Ahmad b. Hanbal say: He was asked : How retaliation of a tooth is taken ? He said: It is broken with a file.