Ectopic eruption of a lower permanent molar from the mediaeval necropolis of Alcáçova do Castelo, Mértola, Portugal.

The mediaeval necropolis of Alcáçova do Castelo is located in Mértola, Southern Portugal, and dates from the 14th to the 16th centuries. The archaeological campaigns started in 1978 and continue today, having yielded more than 759 graves. This report discusses an ectopic tooth eruption observed in skeleton 535, an adult female individual. A distal right permanent lower molar presents an ectopic eruption at the posterior margin of the coronoid process. On the opposite side, the first and second permanent molars are present, the left permanent lower third molar is absent and the mandibular ramus cannot be evaluated since it is broken off and lost. Tooth migration (heteropia) is a common pathological condition documented in clinical literature. However ectopic eruption of lower distal molars is a rare event, and there are few known cases. This is the first case described in archaeological populations worldwide.