Ohtani S, Yamamoto K
Department of Forensic Medicine, Kanagawa Dental College, Japan.
J Forensic Sci. 1992 Jul;37(4):1061-7.
In a study of age estimation from teeth by means of measuring racemization of aspartic acid (Asp), a representative amino acid, the accuracy of data from enamel and dentin in the same tooth was compared. The correlation of D/L ratio of aspartic acid with actual age gave the following parameters: r = 0.928, sigma = +/- 5.2, k = 4.47 x 10(-4) yr-1 in enamel and r = 0.995, sigma = +/- 1.4, k = 5.75 x 10(-4) yr-1. The difference in ages between one estimated by the D/L ratio and the actual one was within +/- 3 years in dentin, while in enamel an error of from 2 to 11 years was observed. Reaction rate constants of the racemization in a dry postmortem state (15 degrees C) were calculated as k = 9.70 x 10(-8) yr-1 in enamel, and k = 1.33 x 10(-7) yr-1 in dentin. Compared to rates determined from teeth recently extracted from living subjects, the rate was higher in dentin than in enamel. These data reconfirmed that dentin is superior to enamel in making exact age estimations from teeth.
在一项通过测量代表性氨基酸天冬氨酸（Asp）的消旋作用来从牙齿估计年龄的研究中，对同一颗牙齿牙釉质和牙本质数据的准确性进行了比较。天冬氨酸的D/L比率与实际年龄的相关性得出以下参数：在牙釉质中，r = 0.928，σ = ±5.2，k = 4.47×10⁻⁴ 年⁻¹；在牙本质中，r = 0.995，σ = ±1.4，k = 5.75×10⁻⁴ 年⁻¹。通过D/L比率估计的年龄与实际年龄之间的差异在牙本质中为±3岁以内，而在牙釉质中观察到的误差为2至11岁。在干燥的死后状态（15摄氏度）下消旋作用的反应速率常数计算得出：在牙釉质中k = 9.70×10⁻⁸ 年⁻¹，在牙本质中k = 1.33×10⁻⁷ 年⁻¹。与从活体近期拔除的牙齿所确定的速率相比，牙本质中的速率高于牙釉质中的速率。这些数据再次证实，在从牙齿进行精确年龄估计方面，牙本质优于牙釉质。
