Analysis on unidentified cases in which dental information was collected from 2014 to 2019 in Miyagi Prefecture, Japan

This study aimed to summarize the characteristics of unidentified cases in which dental information was collected during 2014–2019 in Miyagi Prefecture and to discuss the challenges and social characteristics of dental identification in routine forensic work. Cases were selected and examined from the database of dental charts collected at Tohoku University and the database of the Miyagi Prefectural Police. The annual percentage of cases with matched dental findings ranged from 19.2 − 37.1%, and 80.6% of the cases were identified within four days using dental information. The most common age group was the 50–70 s. Males were more common in the 20–70 s, whereas females were more frequent in the 80–90 s age group. Utilization of dental information was lower for cases involving young people and those over 90 years of age. The number of unidentified cases and unspecified death cases in the central block was significantly higher than other regions. However, there were no significant differences in sex, age, and season between each region. Spearman's rank-order analysis of the unspecified deaths showed a strong correlation with the monthly average temperature (ρ = 0.89, p < 0.01). Within the limitations of this study, the results provide valuable information on the long-term progress of routine dental identification work and could be useful as a reference for a statistical survey. Future research must examine the role of dental information in forensic identification by exploring the role of more specific background characteristics among autopsy cases.