A root canal procedure becomes necessary when infection or inflammation develops in the pulp tissue of the tooth. Pulp tissue consists of blood vessels, connective tissue and nerve cells - which explains why intense pain can always be a risk during a procedure. In time, the pain may go away... at least temporarily. Without any treatment, however, the infection will not disappear. It can lead to a dental abscess, and may even contribute to systemic problems in other parts of the body.
How do you know when you need a root canal? Sometimes, the pain you feel makes it an obvious need. If you feel constant and severe pain and pressure in your mouth, or noticeable swelling and extreme sensitivity in your gums, then it's clear you need an evaluation and treatment as soon as possible. Another symptom of pulp tissue damage is sharp pain when you bite down on food. Lingering pain after eating foods that are really hot or really cold is also an indication of potential trouble. If any of these symptoms arise, you need to have an examination as soon as possible.