Purity: Burial of Separated Body Parts
Practical Laws of Islam as per the teachings of Ayatullah Sistani
Ruling 613:
If a part of the corpse becomes separated – even if it is its hair, nail, or tooth – it must be buried with the body. In the event that the separated part is found after the body has been buried, then based on obligatory precaution, even if it is its hair, nail, or tooth, it must be buried in a different place. Furthermore, it is recommended to bury nails and teeth that were separated from a person’s body when he was alive.
-Ayatullah Sistani, Practical Laws of Islam, Purification (Taharah)