When a tooth becomes infected, the treatment options include either root canal therapy or having the tooth removed. In most cases, root canal is the preferable choice, because it is the only way to save the tooth. Root canal consists of the dentist making a small hole in the tooth and then removing the tiny nerves and blood vessels within the root(s). The roots are then shaped, disinfected, and filled with an inert material. The procedure is usually painless, and is successful about ninety percent of the time when properly preformed. Of course, this also means that about ten percent of the time, a root canal will become re-infected or "fail", and continue to cause problems for the person.
When a tooth with root canal is successful, a person will have no pain or other signs of infection. A root canal that is failing will usually continue to cause pain or discomfort, especially when biting down. In some cases, a failing root canal will cause swelling, also known as an abscess. There are several reasons why a tooth that has root canal can fail. A root canal can fail if some of the infected nerves and blood vessels are left inside the roots, the inert filling does not completely seal off the roots from bacteria, the tooth is damaged during the procedure (perforation), or the tooth fractures between or within the roots. A root canal can fail within days, weeks, months or even many years after the procedure has been completed.
Even if a root canal fails, there are options available. In many cases, the root canal can be re-treated. The old inert filling is removed; the roots are reshaped and disinfected, and then re-filled. If this is not possible, a procedure called an apicoectomy can be preformed. An apicoectomy involves having the tip of the root surgically removed, and then placing a filling over the severed root tip. Although some dentists may recommend an apicoectomy as the initial remedy, it is usually prudent to consider re-treating the root canal first, if at all possible. Proper re-treatment of the root canal can cause less discomfort and may be more successful than an apicoectomy. If these measures fail, the tooth may have to be removed.
The success of root canal is highly dependent on the skill, experience and technique of the dentist performing it. Some dentists may not feel comfortable providing root canal therapy, and may elect to send their patients to a root canal specialist (an endodontist) for treatment. Root canal therapy is both safe and effective, and new techniques may prove to build upon the already high success rate.