Root canal treatment is usually very successful. However, if the infection comes back, the treatment can sometimes be repeated. This would usually be carried out by a specialist endodontist. What if I don’t have the treatment? The alternative is to have the tooth out. Once the pulp is destroyed it can’t heal, and it is not recommended to leave an infected tooth in the mouth. Although some people would prefer to have the tooth out, it is usually best to keep as many natural teeth as possible.