Li Mu-Jia, Chu Guang, Han Meng-Qi, Chen Teng, Zhou Hong, Guo Yu-Cheng
Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, 98 XiWu Road, Xi'an, 710004, Shaanxi, PR China; Department of Orthodontics, Stomatological Hospital of Xi'an Jiaotong University, 98 XiWu Road, Xi'an, 710004, Shaanxi, PR China.
College of Medicine and Forensics, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an 710004, Shaanxi, PR China.
Forensic Sci Int. 2019 Aug;301:76-81. doi: 10.1016/j.forsciint.2019.05.015. Epub 2019 May 15.
The Kvaal method as a non-invasive method for age estimation based on the changes of pulpal size caused by secondary dentin deposition has been applied to different ethnics. However, its results are often conflicting and its accuracy is relatively poor. This study aimed to verify the applicability of the Kvaal method to estimate the ages of the Chinese population using digital panoramic radiographs and to formulate specific regression equations for use in Chinese subjects. A sample of 360 digital panoramic radiographs from northern Chinese population were selected, from which the pulpal size and width of six tooth types (maxillary central incisor, lateral incisor, second premolar, mandibular lateral incisor, canine, and first premolar) were measured using Kvaal's method. Then, inter- and intra-observer reliabilities were calculated to evaluate the reproducibility of those measurements. The correlation between chronological age and measurements was also examined and the Chinese-specific equations for age estimation were conducted. After comparing the accuracy of the Chinese-specific equation with the original Kvaal equation, the age of the Chinese population was clearly overestimated by Kvaal's equation, and a Chinese-specific equation could ameliorate age prediction accuracy. In addition, the residuals of the Chinese-specific equation were significantly lower than that of the original Kvaal's method. Thus, we concluded that the original Kvaal equation cannot accurately estimate age in the Chinese population. Although accuracy improved using the Chinese-specific equation that was based on Kvaal's methodology, the standard deviation remained large. In view of the lack of accurate age estimation methods for adults, we propose finding more correlated variables or combining other age estimation methods to increase the accuracy for adult age estimation.
Kvaal方法作为一种基于继发性牙本质沉积导致的牙髓大小变化的非侵入性年龄估计方法，已应用于不同种族。然而，其结果往往相互矛盾，准确性相对较差。本研究旨在验证Kvaal方法在使用数字化全景X线片估计中国人群年龄方面的适用性，并制定适用于中国受试者的特定回归方程。选取了360例来自中国北方人群的数字化全景X线片样本，采用Kvaal方法测量其中六种牙型（上颌中切牙、侧切牙、第二前磨牙、下颌侧切牙、尖牙和第一前磨牙）的牙髓大小和宽度。然后，计算观察者间和观察者内的可靠性，以评估这些测量的可重复性。还检查了实际年龄与测量值之间的相关性，并推导了中国人群特定的年龄估计方程。将中国人群特定方程的准确性与原始Kvaal方程进行比较后发现，Kvaal方程明显高估了中国人群的年龄，而中国人群特定方程可提高年龄预测准确性。此外，中国人群特定方程的残差明显低于原始Kvaal方法。因此，我们得出结论，原始Kvaal方程不能准确估计中国人群的年龄。尽管基于Kvaal方法的中国人群特定方程提高了准确性，但标准差仍然较大。鉴于缺乏针对成年人的准确年龄估计方法，我们建议寻找更多相关变量或结合其他年龄估计方法，以提高成年人年龄估计的准确性。
