An untreated cavity can infect the pulp (“nerve”) of the tooth and cause inflammation and possibly an abscess. At times, the pulp (nerve) can become necrotic (dead) for unknown reasons and lead to problems.
A root canal treatment is performed to clean out this unhealthy tissue inside the tooth and medicate the tooth as to relieve pain and instigate healing.
The canals of the tooth are filled and sealed, and a restoration (typically a crown) is done to repair damage done by the cavity and protect the tooth for time to come.
A tooth that has had a root canal can usually be restored to last as long as any other tooth. Preventive care plays a big part in long term success.
With modern dentistry, most root canal treatments can be performed with little to no discomfort during the procedure. Post-operative discomfort can be treated with medication, if needed.
The cost of a root canal and a restoration is usually less than the cost of removing that tooth and replacing it with an artificial one.