Root canal treatment is only required when dental X-rays show that the pulp has been damaged by a bacterial infection. Infections are caused by tooth decay, traumatic damage such as a crack, or repeated dental treatments. Any of these causes may lead to acute inflammation known as an abscess. An abscess forms when tissues in the tooth swell. Symptoms of an abscess range from mild to severe toothache to irreversible damage to the pulp. Root canal treatment is necessary when the pulp, the soft tissue inside the root canal, becomes inflamed or infected. If root canal therapy is not done, the pulp may die, or other chronic infections like gum disease may arise.