Most personal identification techniques using dental forensics involve a direct comparison of analog images of the oral cavity with preexisting dental charts. Nevertheless, for the forensic identification of individuals, more efficient and faster methods are required. The progression in digital technology in dentistry has been remarkable, and oral scanning and digital X-ray imaging devices are now used routinely in dental practice. We report a new personal identification technique using intraoral Standard Triangled Language (STL) data, which were obtained using a digital intraoral scanner. We compared the STL data from two virtual corpses with those from a larger population of dental clinic patients to investigate whether the corpses could be identified based solely on the dental impression data. We applied the following two methods: analysis of the area of the three virtual planes connecting the cusp tip of the three adjacent molars (method A) and analysis of the area of the virtual three planes connecting the bulge of each of the three molars (method B) . No virtual corpse could be identified with either of the methods with a margin of error of 0 mm 2 . Method A was able to perform the screening without omitting the individual within a margin error of ≥± 4 mm 2 to obtain a positive result from the screening. In method B, the error range had to be increased to ≥±5 mm 2 . Method A was able to search more accurately than method B, possibly because of the large standard deviation of the measured values across the two teeth. Method B might require multiple measurements to obtain accurate search results. In conclusion, we suggest that our new method could improve the efficiency of personal identification.

The identification of corpses is according to physical characteristics. Among these, teeth are often used for personal identification because they are insusceptible to post-mortempostmortem alterations. Recently, different types of digital data, like optical impressions, have been employed in dentistry. This research identified three indices on the teeth of Standard Triangled Language (STL) data collected using optical impression-taking and evaluated the possibility of personal identification by examining the area of the triangle obtained from three indices. STL data generated from intraoral plaster models (n ＝140) were fabricated virtual antemortem (VAM) data. STL data collected directly from the intraoral cavity (n ＝24) were employed as virtual post-mortempostmortem (VPM) data. Three indices were identified for each first premolar, second premolar, and first molar. Two techniques were devised to find the three points. The area of the triangle created utilizing the three measurement points were employed to assess the conditions under which each VPM data could be excluded from the VAM data group. Although no significant difference existed between the two techniques, one method was preferred for screening. Optimal conditions for both methods were screening carried out with two teeth, including the second premolar. In both methods, only the individual was screened out of 140 individuals when the second premolar was added in the two-teeth condition. This study demonstrated the possibility of personal identification by assessing the area obtained using three measurement points on teeth as indices, indicating a potential application in forensics in the future.