Some more information about root canals
Inside your tooth, beneath the white enamel and a hard layer called dentin, is a soft tissue called pulp. This tissue contains blood vessels, nerves, and connective tissue, which help grow the root of your tooth during its development. A fully developed tooth can survive without the pulp because the tooth continues to be nourished by the tissues surrounding it.

Endodontic treatment is necessary when the pulp, the soft tissue inside the root canal, becomes inflamed or infected. The inflammation or infection can have a variety of causes: deep decay repeated dental procedures on the tooth or a crack or chip in the tooth. In addition, an injury to a tooth may cause pulp damage even if the tooth has no visible chips or cracks. If pulp inflammation or infection is left untreated, it can cause pain or lead to an abscess.