Root Canal Treatment or endodontic therapy becomes necessary as a treatment for the infected or necrotic pulp of a tooth. Pulp infections may progress without symptoms and can be detected through regular dental examination, but commonly involve severe toothache. A tooth's nerve and pulp can become irritated, inflamed and infected due to deep decay, overstress of teeth, periodontal disease or root exposure. Often the treatment will involve the replacement of older insufficient root canal fillings as a cause of inflammation.