[Migration of a retained premolar into the processus muscularis of the mandible].

Migration of an impacted mandibular premolar is a rare finding, whereas dystopia of lower jaw cuspids is described much more often in the literature. We present a patient in whom radiographic studies show the migration of a mandibular premolar to the muscular process over a period of 14 years. Most of the tooth migration along the vertical portion of the mandibula into the processus muscularis took place after the root development had ended.