Investigation on the age estimation from dentin with an amino acid racemization method.

在调查期间，获得了以下结果。1.在年龄估计方面，用L-天冬氨酸和D-天冬氨酸的混合物制成的人工标准样品代替传统上需要的对照牙，能够准确地估计年龄。2.研制了天冬氨酸(Asp)专用FS柱，可在5分钟内将D型和L分离。3.天冬氨酸在牙槽骨中的消旋率远低于前人研究的股骨外消旋率。这一结果表明，牙槽骨比股骨表现出更活跃的代谢。关于消旋率的性别差异也被观察到。4.牙本质消旋率在人和猛犸象中的比较结果表明，后者的消旋率较低，两组牙骨质侧的消旋率都较高。5.用外消旋方法估计年龄的最佳指示剂是天冬氨酸，因为几乎没有发现使用其他氨基酸的报道。但是，如果可以开发其他氨基酸，将增加该方法的可靠性，因此，除天冬氨酸外，还检测了谷氨酸(Glu)和丙氨酸(Ala)。结果发现，谷氨酸和丙氨酸有足够的潜力用于利用样品中的可溶性成分进行年龄估计。6.下颌骨消旋率检查显示，下颌升支、下颌体下部和下颌体上磨牙区的消旋率分别高于下颌体部、下颌体部上部和下颌体部上部的前部。从这些结果，消旋率是不同的骨面积的不同。7.根据模拟烧伤牙齿的加热实验结果，提出了利用色度计进行深褐色牙齿年龄估计的可能性。

During the investigation period, following results were obtained. 1. On age estimation, accurate age was able to be estimated by using artificial standard samples that were made by mixtures of L-and D-aspartic acid, instead of a control tooth conventionally required. 2. A special FS column was fabricated for aspartic acid (Asp) that can separate type D and L distinctly within 5 minute. 3. The racemization rates of Asp from the alveolar bone presented extremely lower value than that of the femur previously investigated. This result indicated that the alveolar bone showed more active metabolism than the femur. The gender differences regarding the racemization rates was also observed. 4. The results of comparison between the racemization rates of dentin in humans and mammoths showed that lower values on the latter and both groups showed higher values on the cementum side. 5. The optimum indicator for age estimation using racemization method is considered to be Asp since almost no reports using other amino acids have been found. However, if other amino acids can be exploited, reliability of this method will be increased, therefore; besides Asp, glutamic acid (Glu) and alanine (Ala) were tested. As a result, it was found that Glu and Ala have sufficient potential to be used for age estimation by using soluble components of samples. 6. Examination of the racemization rates of the mandible revealed that the mandibular ramus, the lower part of the mandibular body, and the molar region of the upper part of the mandibular body showed higher rates than the mandibular body, the upper part of the mandibular body, and the anterior region of the upper part of the mandibular body, respectively. From these results, racemization rates were different depending upon the area of bone. 7. According to the result of the heating experiment simulating teeth from a burned body, it was suggested that estimation of age from dark brown teeth is possible by using a colorimeter.