Hassan Qudsia, Rakha Allah, Bashir M Zahid
Department of Forensic Medicine and Toxicology, Ziauddin University, Karachi.
Department of Forensic Sciences, Quality Assurance Cell, University of Health Sciences, Lahore.
J Coll Physicians Surg Pak. 2017 May;27(5):283-287.
To estimate age through aspartic acid racemization of human dentin for forensic analysis, and to calculate the margin of error between chronological age and estimated age by racemization method.
Cross-sectional comparative study.
Dental Outpatients' Department, Ziauddin Hospital, Karachi, from 2011 to 2014.
Patients from dental orthodontics department were selected. Verbal expressed consent was taken from the participants. Preliminary data was entered in a specially designed performa having name, chronological age, gender, socio-economic status. Land D ratio of aspartic acid were quantified in dentin for each tooth by High-Pressure Liquid Chromatography technique. Results of 100 samples with known age were used during study to estimate co-efficient of racemization. Regression equation was derived by plotting 85 samples of known age and KR as independent and dependent variables and least square equation was derived - Age = -4.391 +347.396 (co-efficient of racemization).
The estimated co-efficient of determination was 0.74, meaning thereby that the regression equation was 74% correct for estimating age. The calculated correlation between chronological age and co-efficient of racemization was 0.834, which is interpreted as a very strong and positive correlation. The co-efficient of racemization increased with the age. The mean chronological age (38.44 ±13.22) years were statistically similar to the mean calibrated age (37.52 ±12.36) years. The median of actual and calibrated age was found to be 3.4 with inter-quantile value of 13. No statistically significant difference was observed among gender (p=0.837), or socioeconomic status (p=0.35).
Racemization of human dentin could be used as one of the reliable method for estimating age. HPLC is a reliable technique to estimate the co-efficient of racemization because it is highly reproducible, cost-effective and convenient. However, the procedure should be optimized and standardized within all laboratories for quality assurance.
通过人牙本质中天冬氨酸消旋化来估计年龄，用于法医分析，并计算实际年龄与消旋化法估计年龄之间的误差范围。
横断面比较研究。
2011年至2014年，卡拉奇齐亚丁医院牙科门诊。
选取牙科正畸科患者。获得参与者的口头同意。将初步数据录入专门设计的表格，内容包括姓名、实际年龄、性别、社会经济地位。采用高压液相色谱技术对每颗牙齿牙本质中的天冬氨酸L/D比值进行定量。研究期间使用100个已知年龄样本的结果来估计消旋化系数。通过绘制85个已知年龄样本和KR作为自变量和因变量，得出回归方程，最小二乘方程为 - 年龄 = -4.391 + 347.396（消旋化系数）。
估计的决定系数为0.74，这意味着回归方程在估计年龄方面的正确率为74%。实际年龄与消旋化系数之间的计算相关性为0.834，这被解释为非常强的正相关。消旋化系数随年龄增加。实际平均年龄（38.44 ± 13.22）岁与校准平均年龄（37.52 ± 12.36）岁在统计学上相似。实际年龄和校准年龄的中位数为3.4，四分位数间距为13。在性别（p = 0.837）或社会经济地位（p = 0.35）方面未观察到统计学上的显著差异。
人牙本质消旋化可作为估计年龄的可靠方法之一。高压液相色谱是估计消旋化系数的可靠技术，因为它具有高度可重复性、成本效益高且方便。然而，为确保质量，该程序应在所有实验室中进行优化和标准化。
