A root canal is designed to treat an infection of the pulp—the inner tooth and nerves. The pulp can become infected as a result of numerous causes, including untreated cavities or damage that develops after a break, chip, or injury. These nerves send signals to the brain to warn you of the infection that are translated as pain and sensitivity, which can make eating and normal activities difficult. Furthermore, if left untreated, an abscess may form, which can lead to more significant health problems and extreme discomfort. Common symptoms of an infection may include: