Should a tooth crack after a root canal?

Roots do not grow back once a dentist drills into the tooth and removes the pulp (the roots and tissue inside the tooth). After that, it is dead and it cannot grow back. Make sure that the dentist (after he fits the crown but before it is permanently sealed) does an X-ray of the tooth to make sure the crown that was ordered properly fits the tooth. Sometimes to the human eye it appears so, but an X-ray can reveal the tiniest opening, which can lead to a re-infection and necessity of the tooth to be pulled.