Concrescence of a mandibular third molar and a supernumerary fourth molar: report of a rare case.

Concrescence represents a rare developmental anomaly in which two fully formed teeth are joined along the root surfaces by cementum. Maxillary molars are the teeth most frequently involved, especially a third molar and a supernumerary tooth. Very few cases have been reported about the concrescence of a third molar and a supernumerary tooth. According to our current knowledge, this case report is the first in the literature in which concrescence is observed between a third molar and a supernumerary fourth molar in the mandible.