A Case of an Impacted Lower Third Molar which Migrated to a Position Inferior to the Coronoid Process Over a 12-Year Period

Abstract

Despite the considerable amount of literature on the positioning of ectopic impacted third molars, few reports have described cases of distal movement in the jawbone. In the present study, we describe our experience in treating a patient whose impacted lower third molar migrated over a 12-year period from the distal region of the second molar to a position inferior to the coronoid process.
The patient was a 37-year-old man who first visited our facility in April 2012 with a chief complaint of right facial swelling and pain. Radiography revealed complete inverse impaction of the lower right third molar into a position inferior to the coronoid process, with a cyst-like radiolucent area including the crown spreading to the distal region of the lower right second molar.
A radiograph from 12 years earlier showed that the lower right third molar was horizontally impacted distal to the lower right second molar. We therefore concluded that this lower right third molar had migrated apically over a 12-year period due to being displaced by the coronal lesion. Histopathological assessment indicated that the lesion was a dentigerous cyst. It is now 1 year since we performed the surgery and the patient has made good progress without any relapse to date.