Internal resorption is an unusual condition of a tooth when the dentin and pulpal walls begin to resorb centrally within the root canal. The first evidence of the lesion may be the appearance of a pink-hued area on the crown of the tooth; this condition is referred to as pink tooth of Mummery, after the 19th century anatomist James Howard Mummery, and represents the hyperplastic, vascular pulp tissue filling-in the resorbed areas.
The cause can sometimes be attributed to trauma to the tooth, but other times there is no known etiology. If the condition is discovered before perforation of the crown or root has occurred, endodontic therapy (root canal therapy) may be carried out with the expectation of a fairly high success rate.
The fact remains that for many afflicted by Internal Resorption, the cause is actually unknown as it cannot be tied to a specific injury or traumatic incident. This has become so prevalent that the Internal Resorption Research Project has been created to anonymously collect data from these individuals to determine if there are any common threads or trends that may help determine the cause.