Dental identification in routine forensic casework: clinical and postmortem investigations.

The aim of this study was to examine the factors which may disturb dental identification of unknown human remains and the practical value of dental evidence in routine forensic casework, including the changes due to dental treatment and postmortem interference. In the investigation of changes due to dental treatment on 696 patients' dental history at two clinics, increase of the number of dental restorations was the greatest in the initial 1-2 years. This finding suggests that dental treatments performed in early period after initial examination contributes more to forensic dental identification than those performed afterwards. The lower anterior teeth (incisors and canines) remained relatively unchanged for years compared with other teeth. The molars appeared to be more frequently restored at a relatively younger age and more frequently missing in the elderly. The investigation of 260 unknown remains in 971 forensic autopsy cases during a period of seven years (1992-1998) at our institute indicated the particular usefulness of dental evidence in cases where the candidates were identified from some other evidence, and usually in cases having a postmortem period corresponding to the obligatory preservation term for the clinical dental records and radiographic films. There were non-identity in the status of dental treatments between ante-mortem dental findings due to additional treatments received after the last day of examination recorded in the corresponding clinical dental records. Postmortem damage from decomposition and fire was more frequently observed in the anterior teeth. These observations indicate that precise documentation of dental evidence including postmortem deterioration and the establishment of a well-organized dental database of missing persons together with a suitable screening system is required to more effectively utilize dental evidence in routine forensic casework.