On September 14, 1997, a dead body of a female was found on a path in Chiba Prefecture. As a result of judicial autopsy, the cause of death was asphyxia by strangulation. Although the body and clothes were intact, the post-mortem interval was estimated only several hours, due to the insufficient information for any positive identification, Chiba Prefectural Police Headquaters requested to exam by dental findings to us. The examination was carried out soon, and the X-ray examination was performed using the Compuray beside the body (Fig. 6). As a result, we judged the body's age was 17(}1) years old from calcification degree of unerupted mandibular third molars (Fig. 8) and others.