Prolonged retention of primary teeth and TMD from the archaeological sample in the Edo Japanese

Prolonged retention of bilateral primary second molars was observed in ancient human skeletal remains excavated from temple ruins of the middle to late Edo period in Japan. Radiographs showed no sign of bilateral second premolars which appeared to be congenitally missing. Furthermore, there was inflammatory deformation of the left mandibular condyle, and pseudarthrosis at the articulation with the left mandibular fossa and a small hole on the articular surface were observed. The case of this study is a rare case in which prolonged retention of bilateral primary second molars was speculated to have resulted in malocclusion, which in turn might have led to temporomandibular disorder. In addition, this case is reported here because its information is thought to be applicable to clinical practice in modern dentistry.