Personal Identification by Superimposition of Three-dimensional Intraoral Models

Victim identification following disasters is an important task for the dentist. Use of records of previous dental treatment proved effective in victim identification after the crash of Japan Airlines Flight 123 in 1985. This dental identification procedure can be problematic, however. In exceptional cases, the victim may have had very little or no prior treatment, making identification by this means impossible. The purpose of this study was to establish a new method of dental identification based on morphological comparison of the oral cavity, rather than on evidence of prior dental treatment. This new method involves superimposing 3-dimensional (3-D) models created by digital impression-taking devices, use of which is becoming increasingly widespread in present-day dental treatment. A total of 75 dental models were used to obtain 3-D models. These were then used in a total of 77 superimposition tests. The results demonstrated that the degree of similarity was 98.03－41.30%, and the degree of difference 0.17－29.69%. This indicated that differences among the dental models could be identified with 100% precision. Personal identification by superimposition of such 3-D models offers a useful tool that could compensate for the shortcomings of standard dental identification.