Age Estimation Using the Racemization of Amino Acid on Human Teeth

为了更准确地估计牙齿年龄，对牙本质中天冬氨酸的外消旋化（D/L比）进行了研究。1. pH的影响：通过加热实验研究了pH（4和9）对牙齿的影响，以精确估计死亡年龄。固定剂的影响：我们研究并比较了保存在95%乙醇、10%福尔马林和10%中性福尔马林固定剂中牙本质天冬氨酸消旋化的进展程度。保存于10%中性福尔马林中的牙本质天冬氨酸外消旋化率最高，其次是保存于10%福尔马林中的牙本质天冬氨酸，然后是保存于95%乙醇中的牙本质天冬氨酸。在15 ℃保存的牙齿中，几乎没有外消旋化的进展。3.粉红色牙齿的影响：利用牙本质天冬氨酸的外消旋化，从粉红色牙齿估计年龄。这些结果表明，估计年龄的粉红色的牙齿可能被低估，但一个更准确的年龄估计后，可以得到充分的清洗。4.年龄估计的外消旋化率使用加热的牙齿：该比率是高于在加热的牙齿比未加热的总氨基酸，但大致相同的可溶性肽。这些结果表明，从D/L比的牙本质可溶性肽烧伤身体的年龄计算是足够准确的这个参数被用来估计年龄的牙齿烧伤身体。

An investigation into racemization of aspartic acid in dentin (D/L ratio) was carried out for the realization of a more accurate dental age estimate.1.Influence of pH :The influence of pH (4 and 9) on teeth was investigated by a heating experiment for precise estimation of age at death. The reaction rate was highest in dentin in a pH 9 environment, followed by that in water, that in a pH 4 environment, and that in a dry state.2.Influence of fixative :We investigated and compared the degree of progression of racemization of dentinal aspartic acid in teeth stored in 95% ethanol, 10% formalin, or 10% neutral formalin fixatives. The racemization rate of dentinal aspartic acid in teeth stored in 10% neutral formalin was the highest, followed by that for teeth stored in 10% formalin then that for teeth stored in 95% ethanol. Teeth stored in these fixatives at 15ﾟC showed almost no progression of racemization.3.Influence of pink teeth :Age was estimated from pink teeth utilizing the racemization of dentinal aspartic acid. These results suggest that age estimated from pink teeth are probably underestimated but that a more accurate age estimate can be obtained after adequate washing.4.Age estimation from racemization rate using heated teeth :The ratio was higher in heated than in unheated teeth for total amino acid, but approximately the same for soluble peptide. These results suggest that age calculated from the D/L ratio of dentinal soluble peptide from burned bodies is sufficiently accurate for this parameter to be used to estimate age in teeth from burned bodies.