What is a common indication for performing a root canal?

Performing a root canal is commonly indicated when there is severe tooth decay or an abscess. In cases of extensive decay, the pulp of the tooth, which contains nerves and blood vessels, can become infected or inflamed. This condition can lead to pain and requires intervention to save the tooth. An abscess, which is a localized collection of pus caused by infection at the root of the tooth, can also create similar symptoms, necessitating a root canal procedure to remove the affected pulp and prevent further complications, such as spreading the infection or losing the tooth.

The other options relate to different dental procedures or concerns that do not specifically require a root canal. Whitening discolored teeth focuses on cosmetic enhancement rather than addressing dental health issues. Replacing lost teeth usually involves prosthetics like implants or dentures, rather than root canal therapy. Preparing for braces is related to orthodontic treatment, which may address alignment but does not involve the endodontic procedures characteristic of a root canal.