Development of time since death estimation method using teeth in a body immersed in water

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K17383
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Social dentistry
• Research Institution: Tokyo Dental College
• Principal Investigator: Ishikawa Noboru 東京歯科大学, 歯学部, 講師 (10772288)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 法歯学 / 死後経過時間 / 水中死体 / 身元不明死体

Outline of Final Research Achievements

The purpose of this study was to develop a new method for estimating time since death for immersed bodies. The change in the amount of deposits on the tooth surface with time was analyzed using the Electron Probe X-ray Micro Analyzer. As a result, the estimation formula of time since death for the immersed body could be calculated. In addition, when the difference in water component (sea water, river water, lake water) was examined, it was suggested that it is necessary to calculate each formula by classifying it into seawater and freshwater based on the difference in the contained components. In this study, we focused on seawater and calculated the regression equation.

Free Research Field

法歯学

Academic Significance and Societal Importance of the Research Achievements

死後長期に経過した死体は、腐敗の影響から死後経過の推定は徐々に困難になる。さらに白骨化した場合においてはその傾向が顕著である。さらに水中死体の場合は死亡現場（あるいは入水現場）と発見現場が異なることがほとんどであるため、死体の身元確認のためにも死後経過時間の推定は重要である。本研究ではその点に要点を置き、法歯学的観点から死後経過時間の推定式の算出を行った。