Idiopathic dental root replacement resorption in old dogs.

The roots of the teeth of 33 large dogs aged 10 years or older were radiographed. These dogs were euthanized for reasons other than oral diseases; dogs with obvious dental or periodontal diseases were excluded. The dogs had shown no clinical signs related to the teeth and the teeth were macroscopically normal. Of the 33 dogs, six had one or more teeth that had abnormally shaped and partially resorbed roots, with replacement of root structure by radiographically normal trabecular bone. Histological examination of radiographically abnormal roots revealed mid-root resorption, without signs of inflammation or hypercementosis. These findings are similar to the condition known as idiopathic dental root replacement resorption in the human dental literature. Possible etiologies of root resorption are discussed.