Development of standard samples for age estimation using the amino acid racemization method with dentin

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K23018
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0907:Oral science and related fields
• Research Institution: Tokyo Medical and Dental University
• Principal Investigator: Minegishi Saki 東京医科歯科大学, 大学院医歯学総合研究科, 助教 (00882820)
• Project Period (FY): 2020-09-11 – 2023-03-31
• Keywords: 年齢推定 / ラセミ化 / 象牙質 / アスパラギン酸

Outline of Final Research Achievements

The aim of this study is to develop standard samples for age estimation using the amino acid racemization method. Amino acid samples extracted from dentin powder were treated with aspartate transaminase (AST), and changes in the racemization rate due to differences in the amount of AST, reaction time and amount of substrate were investigated. As a result, it was confirmed that the racemization rate increased and decreased in a short time, indicating that it is possible to prepare standard samples. In addition, when the racemization rate of endodontically treated teeth which are relatively easy to obtain as extracted teeth was compared with that of vital teeth, the former was found to be higher than the latter. It was clarified that the racemization rate of treated teeth possibly changed.

Free Research Field

法歯学分野

Academic Significance and Societal Importance of the Research Achievements

ラセミ化法による年齢推定は精度が高い方法として知られているが、手技が煩雑であることや検量線作成のために同歯種の幅広い年代の抜去歯収集が必要になることから実務に積極的に応用されていない。我々はこれまで高温加熱によって人工的にラセミ化率を変えられること明らかにしてきたが、より簡便で安全な方法の開発が必要と考えてきた。本研究では、ASTに着目し、酵素量、反応時間および基質量を変えることで、短時間で安全にラセミ化率の上昇および減少を確認できたことは学術的および社会的意義が大きいと考える。また、失活歯の応用を考える上で、生活歯とはラセミ化率が異なることを明らかにできた点も意義あるものと考える。