Objective To study the accuracy of Nolla method for age estimation of Northern Chinese Han children aged between 5.00 and 14.99 years based on original transformation tables and multiple regression model. Methods A total of 2 000 orthopantomographs （OPGs） were collected from the Hospital of Stomatology, Xi'an Jiaotong University, including 1 000 males and 1 000 females. Development stage of 7 left mandibular permanent teeth （except third molars） was assessed based on Nolla method, then age estimation was conducted through transformation tables and multiple regression model, respectively. Firstly, the development stage results of 7 permanent teeth were added up and the estimated age was obtained through the original transformation tables. Secondly, 80% of the samples （80 males and 80 females in each age group） were randomly selected from 2 000 OPGs as the train set. The chronological age of the selected patients was taken as the dependent variable, while gender and the development stage results of 7 permanent teeth were taken as the independent variable to establish multiple regression model. The remaining 20% of the samples were substituted into the model as the test set, to verify the accuracy of age estimation by multiple regression model. Results Mean chronological ages of males and females were 10.03±0.09 years and 10.01±0.09 years, respectively. The age estimated by original transformation tables showed an overestimation for males （0.18 years on average） and an underestimation for females （0.02 years on average）, with mean absolute error （MAE） of 0.94 years and 0.97 years, respectively. While the results by multiple regression model showed that males were overestimated by 0.06 years on average and females were underestimated by 0.02 years on average. The MAE was 0.66 years and 0.77 years, respectively. Conclusion The Nolla method is suitable for age estimation of Northern Chinese Han children. Compared with the original transformation tables method, the multiple regression model is more accurate for age estimation.
题目: Nolla法推断中国北方汉族儿童年龄的准确性.
摘要: 目的 基于原始表格转换法和多元回归模型，研究应用Nolla法推断中国北方汉族5.00~14.99岁儿童年龄的准确性。 方法 收集在西安交通大学口腔医院就诊的5.00~14.99岁中国北方汉族儿童患者的口腔全景曲面体层摄影片（简称“全口曲面体层片”） 2 000张，其中男性1 000例，女性1 000例。基于Nolla法对下颌左侧7颗恒牙（除第三磨牙外）进行发育分期评估后，分别通过原始表格转换法和多元回归模型进行年龄推断。首先将7颗恒牙的发育分期结果求和，根据年龄转换表获得推断年龄。其次，从2 000张全口曲面体层片中随机选取80%的样本作为训练集（每个年龄段男性、女性各80例），以所选患者的生理年龄为因变量，以性别、7颗恒牙的分期结果为自变量建立多元回归模型。之后将剩余20%的样本作为测试集代入模型，以验证采用多元回归模型进行年龄推断的准确性。 结果 男性样本的平均生理年龄为（10.03±0.09）岁，女性为（10.01±0.09）岁。经原始表格转换法进行年龄推断的结果显示，男性平均高估0.18岁，女性平均低估0.02岁，平均绝对误差（mean absolute error，MAE）分别为0.94岁和0.97岁；通过建立多元回归模型进行年龄推断的结果显示，男性平均高估0.06岁，女性平均低估0.02岁，MAE分别为0.66岁和0.77岁。 结论 本研究基于Nolla法可实现中国北方汉族儿童的年龄推断。相较于原始表格转换法，建立多元回归模型进行年龄推断更加准确。.
关键词: 法医人类学；年龄推断；全口曲面体层片；Nolla法；多元回归模型；中国北方；儿童.
Keywords: forensic anthropology; age estimation; oral panoramic tomography; Nolla method; multiple regression model; Northern Chinese; children.
Copyright© by the Editorial Department of Journal of Forensic Medicine.