Li Mujia, Zhao Jiamin, Chen Wenjie, Chen Xin, Chu Guang, Chen Teng, Guo Yucheng
Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, Xi'an, China.
Department of Orthodontics, Stomatological Hospital of Xi'an Jiaotong University, Xi'an, China.
Forensic Sci Res. 2020 Mar 18;7(2):132-137. doi: 10.1080/20961790.2020.1717029. eCollection 2022.
Due to the secondary dentin formation, the dental pulp undergoes changes in shape throughout life. Based on this phenomenon, the Kvaal method has been applied to various populations for age estimation, and its usefulness has been verified. When applying the Kvaal method to Chinese subjects, we observed a relatively strong correlation between mandibular canines and age. This study notes the correlation between canines and chronological age and is the first to identify which canine is most closely related to chronological age. In addition, a new, simpler formula is determined based on canines according to Kvaal's methodology. The radiographs of 360 individuals from northern China were selected, from which the widths and lengths of the pulp from four canines were measured according to the Kvaal method. Next, inter- and intra-observer reliabilities were analyzed in order to assess the repeatability of these measurements. The correlation between measurements and age was examined, and Chinese-specific age estimation formulae were derived. The results revealed that the ratios from the left maxillary canine exhibited the strongest correlation with age compared to the other canines, whereas the left mandibular canine showed the weakest correlation, which may contribute to the overall poor correlation of mandibular canines with age. What's more, the formula derived from the left maxillary canine in this study displayed the highest coefficients of determination, and the formula derived from all canines showed the lowest residuals. Both of these formulae performed better than the Chinese-specific formula derived from six different types of teeth in our previous study, which had formerly possessed the highest coefficients of determination and the lowest residuals. Thus, we concluded that canines do play an important role in age estimation in the Chinese population, and the correlation between maxillary canines and chronological age is stronger than that of mandibular canines, although no distinct trend as to which side is better correlated with age was established. Going forward, we recommend the analysis of additional samples from different geographical regions and populations to further verify the importance of canines in age estimation.
由于继发性牙本质的形成，牙髓在一生中会经历形状变化。基于这一现象，Kvaal方法已应用于不同人群进行年龄估计，其有效性已得到验证。将Kvaal方法应用于中国受试者时，我们观察到下颌尖牙与年龄之间存在相对较强的相关性。本研究记录了尖牙与实际年龄之间的相关性，并且首次确定了哪颗尖牙与实际年龄关系最为密切。此外，根据Kvaal的方法，基于尖牙确定了一个新的、更简单的公式。选取了来自中国北方的360名个体的X线片，按照Kvaal方法测量了四颗尖牙髓腔的宽度和长度。接下来，分析了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。检查了测量值与年龄之间的相关性，并推导了针对中国人的年龄估计公式。结果显示，与其他尖牙相比，左上颌尖牙的比值与年龄的相关性最强，而左下颌尖牙的相关性最弱，这可能是下颌尖牙与年龄总体相关性较差的原因。此外，本研究中从左上颌尖牙推导的公式显示出最高的决定系数，而从所有尖牙推导的公式显示出最低的残差。这两个公式的表现均优于我们之前研究中从六种不同类型牙齿推导的针对中国人的公式，后者之前具有最高的决定系数和最低的残差。因此，我们得出结论，尖牙在中国人群年龄估计中确实起着重要作用，并得出上颌尖牙与实际年龄的相关性强于下颌尖牙的结论，尽管未确定哪一侧与年龄的相关性更好的明显趋势。展望未来，我们建议分析来自不同地理区域和人群的更多样本，以进一步验证尖牙在年龄估计中的重要性。
