Age estimation by pulp/tooth area ratio in anterior teeth using cone-beam computed tomography: comparison of four teeth

Abstract Objectives Age estimation is one of the most important factors in forensic medicine. Measuring secondary dentin deposition using cone-beam computed tomography images is an easy and noninvasive method. The aim of this study was to evaluate cone-beam computed tomography images as a reliable method to estimate chronological age by pulp/teeth ratio in anterior teeth in Iranian population. Methodology A total of 649 CBCT images from 377 Iranian patients aged between 20 and 69 years were evaluated. Pulp/teeth ratio (PTR) in maxillary and mandibular canine and central incisor teeth was measured in the axial and sagittal sections using OnDemand 3D Dental software. The Pearson correlation coefficient was determined to evaluate the correlation between the variables. Linear regression analysis, as well as age estimation formula, was used for each tooth separately. Results The regression analyses indicated that maxillary central incisors were more reliable for age estimation (R2=0.586 and standard error of estimate=7.045) compared with the other anterior teeth studied. Maxillary canine teeth had the lowest predictive power (R2=0.392 and standard error of estimate=8.387). Also, comparison of the axial and sagittal sections showed that the axial sections had a higher predictive power. (R2=0.48 for axial plans and R2=0.328 for sagittal plans) Conclusion The use of cone-beam computed tomography in age estimation by pulp/teeth ratio of anterior teeth is useful and a reliable method for age estimation in Iranian population.

【摘要】
研究目的：年龄推断是法医学中的关键影响因素之一。利用锥形束计算机断层扫描（cone-beam computed tomography, CBCT）图像测量继发性牙本质沉积，是一种简便且无创的检测方法。本研究旨在评估以锥形束计算机断层扫描图像为基础，通过测量伊朗人群前牙的牙髓牙体比（pulp/teeth ratio, PTR）推断实际年龄的可靠性。
研究方法：本研究共评估了377名年龄介于20~69岁的伊朗患者的649份CBCT图像。使用OnDemand 3D Dental软件，在轴位及矢状位截面中测量上颌尖牙、上颌中切牙、下颌尖牙与下颌中切牙的牙髓牙体比（PTR）。通过计算皮尔逊相关系数分析各变量间的相关性，并针对每颗牙齿分别开展线性回归分析，构建年龄推断公式。
研究结果：回归分析结果显示，相较于本研究中其余受试前牙，上颌中切牙用于年龄推断的可靠性更高（决定系数R²=0.586，估计标准误=7.045）。上颌尖牙的预测能力最低（决定系数R²=0.392，估计标准误=8.387）。此外，轴位与矢状位截面的对比结果表明，轴位截面的预测能力更优（轴位层面R²=0.48，矢状位层面R²=0.328）。
研究结论：利用锥形束计算机断层扫描结合前牙牙髓牙体比开展年龄推断，是一种适用于伊朗人群的可靠且有效的年龄推断方法。