Upper molar root resorption because of distal movement. Report of a case.

A case of a patient whose upper first molars suffered severe root resorption as a result of distal tooth movement is presented. Complete destruction of one root was found to have occurred. The initial objective in treatment was to regain arch length and improve the molar relationships with headgear. Subsequently, full-bonded orthodontic therapy was initiated after extraction of all first molars, as loss of root length could be observed radiographically. Examination of the extracted upper first molar roots in a scanning electron microscope revealed extensive areas of superficial root surface resorption which were not detectable on radiographs of these teeth. Care should be taken to avoid impingement of roots on adjacent unerupted teeth, which may result in extensive root damage.