The goal of root canal therapy is to improve the health of your damaged tooth. During treatment, the pulp is removed from your root canals through a small opening in the crown. Then the canals are cleaned and disinfected. Treatment may take one or more visits. The tooth is first numbed. An opening is made in your tooth and any existing fillings or decay is removed. Then your dentist removes unhealthy pulp with tiny, flexible files. Using delicate, up-and-down motions, your dentist gently cleans and smoothes your canals to disinfect them and prepares them for filling. The canals are then sealed with an inert material that occupies the space vacated by the removal of the pulp. After the inside of your tooth has been treated, the outside will be restored to protect your tooth's underlying structures and to bring the tooth back into function. Your dentist will usually cover the tooth with a ceramic or metal crown.