If dental caries infect the pulp of a tooth or if it is damaged, root canal treatment is often the only way to save the tooth. The pulp, or nerve chamber, is hidden within the hard cover of the tooth. To reach the pulp, the tooth has to be numbed and drilled. Then, the inflamed pulp is removed. Root canals are cleaned out, enlarged and then polished. There are different filling methods. The standard filling material is gutta-percha, a natural elastic material.