Does an impacted tooth cause root resorption of the adjacent one?

External root resorption caused by an adjacent impacted tooth was studied radiographically in 199 cases. Resorption of the root had occurred in fifteen instances (7.5 per cent), the cervical region being least affected. The incidence was highest in the 21 to 30-year-old group and mainly involved male patients. Resorption of the periodontium alone was found in sixteen additional patients; of these, five were followed for 1 year after extraction of the impacted tooth. During this period, the damaged periodontium was completely re-established.