To save/protect the tooth. After the root is removed, the tooth is essentially dead. Without a filling (and eventually a crown in most cases), the tooth would be so brittle that it would shatter.
Root canals are filled to prevent infection deep inside the tooth pulp or nerve. If a root canal is not filled the patient risks post-operative infection inside the tooth that has been worked on and can potentially lose that tooth.
Root canals are typically filled to prevent infection, as well as to reduce the potential of temperature sensitivity and pain in the tooth. It may also be done to improve the structural strength of the tooth.
Root canals are filled in with cement, or gutta percha to avoid any inflammation and irritaion with the exposed nerve of the tooth. Without filling-in, the root becomes infected and the whole tooth may die.
The empty canals will become a breeding place for germs,causing dental problems. If food particles gather in the root canal puss may form to create serioud problems. The filled canals will not allow germs or bacterias to gather to create diseases. It will strenghten the gums also.
