When a person has a severe tooth ache or a badly decayed tooth, the nerves in the tooth are infected and inflamed. Sometimes, the infection can spread down the root and infect the bone. Root canal therapy involves removal of the infected nerve and eradication of the bacteria in the root canal. A dental crown is usually necessary after completion of root canal treatment because of substantial loss of tooth structure. The crown is needed to cover the remaining tooth and prevent fracture.
Success for root canal treatment is not guaranteed. Generally, the success rate for first time treatment is around 90%. For re-treatment cases, it is lower at around 65%. In addition, failures can occur because of leakage under the crown.
Root canal therapy generally is a painless procedure performed under local anesthesia. The dentist should ensure that the patient has profound numbness of the affected teeth before commencing on root canal therapy.