应用Demirjian法进行法医学年龄推断的评价

目的对应用Demirjian法进行法医学年龄推断的准确度及可靠性进行初步评价。方法应用Demirjian法测定828名上海地区青少年(男279名,女549名,11～19周岁)的牙龄,比较所测牙龄和实际年龄的差异。结果在11～14岁年龄段Demirjian法测定的牙龄比实际年龄高估,在15～16岁年龄段低估,在17岁及17岁以上年龄段具有局限性。结论Demirjian法可以用于测定上海地区11～16岁年龄段青少年的牙龄,使用时需进行适当的修正。     

Demirjian法测定广东地区青少年第三磨牙牙龄

目的评估Demirjian法用于测定广东地区青少年牙龄的可行性。方法收集344例(男性171例,女性173例)广东地区9~25岁汉族青少年全口曲面断层片,应用Demirjian法进行分期评定,并比较测得牙龄与生理年龄的差异,分析男女之间的差异性,并分别比较相应分期与16岁和18岁实际年龄的似然率。结果本文344例样本的统计学分析显示,生理年龄与第三磨牙发育程度呈高度相关,相关系数男性为0.837,女性为0.886;Demirjian法分期为D、E、G期的不同性别之间,第三磨牙的发育程度差异具有统计学意义(P0.05);根据样本分期推断的牙龄与相应个体生理年龄的平均差异,女性为0.98岁,男性为0.88岁,其差异具有统计学意义(P0.05);分期为G期的样本与达到以及大于16岁个体似然率男性为85.7%,女性为94.3%,H期与达到以及大于18岁的似然率男性及女性均为100%。结论根据全口曲面断层片对广东汉族青少年牙龄进行推断不能单独采用Demirjian法,需用其他方法综合校正;而分期中的G及H期可用于对16及18岁年龄的推断。     

Nolla法在乌鲁木齐地区维、汉未成年人群中通过牙龄推断年龄的应用

目的 评估应用Nolla法推断乌鲁木齐地区维吾尔族和汉族3～16岁未成年人群年龄的适用性和准确性。方法 收集2019年～2021年新疆医科大学附属口腔医院年龄在3～16岁的乌鲁木齐地区维吾尔族和汉族拍摄的全口曲面体层片1 208例，其中维吾尔族547例（男性：267例，女性：280例），汉族661例（男性：347例，女性：314例）。按照Nolla法分期标准及其提供的年龄转换表获得牙龄。将所得牙龄与生理年龄进行配对t检验。结果 维吾尔族男性平均生理年龄为（8.81±3.75）岁，女性为（9.62±3.68）岁；男性平均低估了0.06岁，女性平均低估了0.52岁；平均绝对误差（Mean Absolute Error,MAE）男、女性分别为0.70岁和0.80岁。汉族男性平均生理年龄为（9.07±3.77）岁，女性为（8.96±3.86）岁；男性平均低估了0.13岁，女性平均低估了0.64岁；MAE男、女性分别为0.69岁和0.90岁。结论 Nolla法适用于除女性15～16岁的乌鲁木齐地区维吾尔族和汉族未成年人群，维吾尔族准确性高于汉族，男性较女性准确。另外，本研究提出了恒牙总成熟度-生...     

青少年第三磨牙发育的分期模式与年龄相关性研究

目的基于改良Demirjian法探讨上海市汉族青少年第三磨牙发育的分期模式与年龄相关性。方法收集1179例6～30周岁上海市汉族个体全口曲面断层片,依据改良Demirjian法(共9阶段)评估样本中第三磨牙所处的发育阶段。采用Mann-Whitney U及Kruskal-Wallis H检验分析不同性别、牙位的第三磨牙发育差异,建立多元Logistic回归模型以评估发育阶段与年龄、性别及牙位的相关性,并统计各发育阶段中年龄超过12、14、16及18周岁的样本比例。结果第三磨牙的发育阶段与年龄呈显著正相关(P0.001),且年龄对于区分各发育阶段(vs阶段1)的影响均具有显著统计学意义(P0.001)。经比较各发育阶段的年龄均值,上颌整体低于下颌(阶段1除外)、男性整体低于女性(阶段B、G除外)。不论性别,阶段E、F、H的样本年龄分别首次全部超过12、14、16周岁,且阶段H中年龄超过18周岁的样本占比最高(男98.7%、女99.2%)。结论上海市汉族青少年第三磨牙发育的分期模式与年龄显著正相关。上颌第三磨牙发育整体早于下颌、男性第三磨牙发育整体早于女性。阶段E～H有望成为判断个体年龄是否已满12、14、16或18岁的有用指标。     

中国北方未成年人群牙龄推断研究

目的运用Cameriere法和Willems法推断中国北方5~14岁人群牙龄,并比较两种方法牙龄推断的准确性。方法收集西安交通大学口腔医院年龄在5~14岁的中国北方未成年人群拍摄的全口曲面断层片2000例,其中男性1000例,女性1000例。分别采用Cameriere法和Willems法进行牙龄推断,利用SPSS 18.0软件对两种方法的推断年龄与生理年龄进行配对t检验,比较推断年龄与生理年龄的差异。结果 Cameriere法的推断年龄比生理年龄平均低估了0.38岁(男性)和0.39岁(女性),而Willems法的推断年龄比生理年龄平均高估了0.61岁(男性)和0.39岁(女性)。对比两种方法的平均绝对误差(mean absolute error, MAE),Cameriere法的MAE为0.87岁,Willems法的MAE为0.91岁。结论 Cameriere法和Willems法均适用于中国北方5~14岁未成年人群的牙龄推断,但Cameriere法比Willems法更准确。     

中国汉族女性青少年法医学活体骨龄推断数学模型的建立

目的建立推断中国汉族女性青少年活体骨龄的数学模型。方法摄取华中、华南及华东等地区的838名年龄介于11～20周岁正常女性青少年双侧锁骨胸骨端以及左侧肩、肘、腕、髋、膝、踝关节的X线片。依据青少年骨发育分级标准对24项骨骼发育指标进行阅片、分级,结合考虑身高、体质量及地区等影响因素．应用SAS8．1及SPSS11．0软件进行统计学处理,探索各指标与年龄的相关性。结果建立了我国汉族女性青少年利用锁骨胸骨端及6大关节骨骺闭合程度联合推断活体年龄的多元回归数学模型．推导出判定我国汉族女性青少年是否已满14、16和18周岁的Fisher’S两类判别分析方程。结论本研究所建立的判定活体年龄的数学模型丰富了活体年龄的法医学鉴定方法,有利于提高活体骨龄鉴定方法的科学性和结论的准确性。     

中国汉族6～18周岁女性人群牙齿生长发育的年龄研究

目的研究牙齿钙化程度与年龄的关系,建立利用牙齿推断中国汉族女性人群年龄的方程。方法通过对6923名6～18周岁汉族女性儿童及青少年全口曲面断层影像下颌恒牙的钙化程度进行评分;将分级值及其对应的年龄输入SPSS软件进行分析,最终建立推断年龄的方程模型;从研究样本外随机抽取已知年龄的样本181例进行肓测。结果牙齿钙化评分值与年龄相关分析结果相关系数r均大于0．6,同名牙评分值侧别间统计分析结果P〉0．05且相关系数r均大于0．93,方程拟合优度检验R^2=0．789,估计值标准误为1．28岁,盲测结果与真实年龄的平均误差为0．421±0．272岁。结论本研究所建立的方法在推断中国汉族女性6～18周岁群体年龄方面有良好的应用前景。     

中国汉族6-18周岁男性牙齿生长发育的年龄研究

目的研究牙齿钙化程度与年龄的关系,建立利用牙齿钙化程度推断中国汉族6～18周岁男性年龄的办程。方法通过对6568名6～18周岁汉族男性全口曲面断层影像上牙齿的钙化程度进行评分;将分级值及其对应年龄输入SPSS软件进行分析,建立推断年龄的方程模型;从研究样本外随机抽取已知年龄的样本160例进行卣测,,结果同名牙齿钙化评分值侧别间秩合检验结果P〉0．05;下颌左侧恒牙钙化评分值与年龄相关分析结果r值均存0．7以上,下颌同名牙间相关系数r均在0．9以上;所建回归模型拟合优度R^2=0．828,估计值标准误为1．23岁;阿测平均洪差为0．423±0．269岁。结论本研究所建立的方法准确可靠,可用于中国汉族6～18周岁男性人群的年龄推断。     

应用放射影像技术进行牙龄推断

牙龄是年龄推断的重要方法之一，国外学者常将其与骨龄联合应用以提高年龄推断的准确性，但国内尚未普遍开展。大量研究表明，应用放射影像学这一无创的检查手段，可以准确观察牙齿的增龄性变化，如牙冠与牙根的发育程度、牙髓腔的变化等。目前应用放射影像学进行牙龄推断的主要方法有Gleiser和Hunt法、Demirjian法及牙髓腔测量法等。其中Demirjian法的准确性最高，但在推断法定敏感年龄时尚存在局限性。随着放射影像学的发展，尤其是CT的出现，依赖其高分辨率以及相匹配的测量软件，可提高牙龄推断的准确性与可靠性，有望成为今后推断活体年龄的重要手段。     

河南省安阳市6-15周岁汉族人牙龄的研究

目的建立利用牙齿钙化程度推断未成年人年龄的方法。方法选取河南省安阳市1575名（男性900名,女性675名）6～15周岁人群的全口曲面断层影像片,依照牙齿钙化分级标准对下颌恒牙钙化程度进行评分分级;所得数据经SPSS13．0软件统计分析,建立根据牙齿钙化程度推断年龄的方程;采用拟合优度检验、模型方差分析、回归系数检验和共线性诊断、残差分析对方程的合理性进行检验及盲测。结果下颌同名牙间钙化分级评分值无统计学差异（P〉0．05）,而下颌同名牙性别间钙化评分值在部分年龄组存在差异（P〈0．05）;下颌恒牙的钙化程度与年龄相关系数r均大于0．7;所建方程模型调整决定系数均大于0．8,估计值标准误男性为0．92岁至1．04岁、女性为0．92岁至1．00岁;推测年龄与真实年龄的平均误差男性为0．433±0．288岁、女性为0．502±0．297岁。结论本研究建立的方法在推断相关地区、相关年龄段人群的年龄推断中有较好的应用前景。     

Validity of Demirjian's and modified Demirjian's methods in age estimation for Korean juveniles and adolescents

In estimating age of juveniles and adolescents, the teeth are employed primarily because of its low variability and less affection by endocrine and nutritional status in development. Demirjian established criteria for evaluating maturity of teeth and his method has been used throughout the world. However, several studies showed the inappropriateness of Demirjian's method on populations other than the one it is based on. Consequently some researchers modified Demirjian's method using data of several different populations. Demirjian himself also published a revised method to overcome other shortcomings of his original method. The aim of this study was to test the validity of Demirjian's and the modified methods (Demirjian's revised, Willems', Chaillet's and new Korean methods) for Korean juveniles and adolescents. 1483 digital orthopantomograms which consist of 754 males and 729 females in the age range of 3-16 years were collected. New age estimation method based on Korean population data was calculated. Dental age was estimated according to each method and the validity was evaluated using the differences between chronological and dental age. The inter- and intra-observer reliability was evaluated to be excellent. Statistically significant difference was observed between chronological and dental age in all the methods for both sexes except new Korean method for both sexes and Demirjian's revised method for males. However, when analyzing absolute and squared value of difference, Willems' method was found to be most accurate followed by new Korean method with slight difference for Korean population for both sexes. In conclusion, both Willems' method and new Korean method conducted by present study were proven to be suitable for Korean population.     

Reliability of the methods applied to assess age minority in living subjects around 18 years old. A survey on a Moroccan origin population

We present a review of a population of 114 immigrant Moroccan males for which an age estimation was requested. The subjects' real chronological age was confirmed by the Moroccan Embassy in Spain. The confirmed age range was between 13 and 25, with an average age of 18.1 years and a standard deviation of 2.03. The following tests were performed to arrive at the forensic estimation of age: general physical examination, carpus X-ray (Greulich and Pyle method) and dental orthopantomography to determine the degree of maturity of the third inferior molars (Demirjian's method). Carpus X-ray (skeletal age) was the most useful method, followed by Demirjian's method (dental age), as prediction factors of a chronological age of over or under 18. The combination of skeletal and dental age variables represented a significant improvement in the prediction of the chronological age of the subjects in this population, reducing the number of ethically unacceptable test errors to a minimum.     

Dental age estimation in Belgian children: Demirjian's technique revisited.

Aim: The purpose of this study was to evaluate the accuracy of Demirjian's dental age estimation in children in a Belgian Caucasian population and to adapt the scoring system in case of a significant overestimation as frequently reported. We selected 2523 orthopantomograms of 1265 boys and 1258 girls, of which 2116 (1029 boys and 1087 girls) were used for estimating the dental age with the Demirjian's technique. The 407 other orthopantomograms were beyond the original age limit. A second sample of 355 orthopantomograms was used to evaluate the accuracy of the original method and the adapted method. A signed-rank test was performed to search for significant age differences between the obtained dental age and the chronological age. A weighted ANOVA was performed in order to adapt the scoring system for this Belgian population. The overestimation of the chronological age was confirmed. The adapted scoring system resulted in new age scores expressed in years and in a higher accuracy compared to the original method in Belgian Caucasians.     

Morphologic analysis of third-molar mineralization for eastern Turkish children and youth

To date, there has been no chronological age estimation according to third-molar mineralization in eastern Turkish children and adolescents. The aim of this study was to analyze the development of the mandibular third molar and its relationship to chronological age in subjects aged 7-22 years according to Demirjian's stages. The final sample consisted of 1348 [622 males (mean age, 12.72 ± 3.14) and 726 females (mean age, 12.92 ± 2.89)] conventional orthopantomograms from eastern Turkish youths. An independent t-test was performed to evaluate the difference between sexes. Regression analysis was performed to obtain regression formulae for dental age calculation with chronological age. In males, there was a difference between males and females only at stage C (p = 0.03); females were advanced 0.37 years compared with males at the stage C. Third-molar development among eastern Turkish children and youths occurs at a more advanced age than other populations for almost all stages.     

The accuracy and precision of third molar development as an indicator of chronological age in Hispanics

The accuracy and precision of chronological age estimation based on the stages of third molar tooth development was studied in a sample of 679 radiographs from individuals of Hispanic origin. The age range was 14.0 to 25.0 years. Eight raters from the University of Texas Health Science Center at Houston Dental Branch evaluated the radiographs according to Demirjian's schematic definitions of crown and root formation. The objective of this study was to evaluate the chronology of third molar development in Hispanics following the protocol of a previous study. Within the Hispanic population, the rate of male third molar development is greater than that of female third molar development for ten stages of crown-root formation. Also within this Hispanic population sample, the rate of maxillary third molar development is ahead of mandibular third molar development. The mean absolute difference between chronological age and estimated age was +/-3.0 years in females and +/- 2.6 years in males.     

Accuracy of different dental age estimation methods on Turkish children

Tooth development is widely used to estimate age or maturation. Dental age estimation is so important for various research works. Numerous methods have been described to estimate dental age based on the dental maturation. The aims of this study were to decide the best method to estimate dental age on Turkish children by reviewing several methods and to illustrate the differences among the methods and to assist future studies. The records of Turkish children between the ages of 7 and 13 years who visited the Department of Pediatric Dentistry of the Faculty of Dentistry of the Süleyman Demirel University in Isparta, Turkey were reviewed and a total of 425 healthy children with complete records, satisfactory panoramic radiographs, similar socio-economic background and ethnic origin were included. Panoramic radiographs were examined with Nolla's, Haavikko's and Demirjian's methods. Dental age was calculated for each method, and the differences between the estimated dental age and the chronological age were compared with paired t-test and Wilcoxon signed rank test. The accuracy of three methods was obtained with ICC (intraclass correlation coefficient). An under-estimation of the dental age was observed by using Nolla's and Haavikko's methods (boys -0.53±0.95, girls -0.57±0.91, both -0.54±0.93; boys -0.60±0.80, girls -0.56±0.81, both -0.58±0.80, respectively) and an over-estimation of the dental age was observed by using Demirjian's method (boys 0.52±0.86, girls 0.75±0.90, both 0.64±0.89). Haavikko's method was more accurate in the dental age estimation compared to the other methods. All of the three methods are not completely suitable for Turkish children and establishment of the population-specific standards is essential and crucial.     

Age estimation of Korean children based on dental maturity

The aim of this study was to evaluate the relationship between age and dental maturity and to establish the standard database of dental maturity based on the Demirjian's stages, which can be used for the age estimation of Korean children. For this purpose, dental maturity was measured by the Demirjian's stages on a randomly selected sample of panoramic radiographs taken from 2706 patients between 1 and 20 years of age and analyzed by multiple linear regression analysis based on the method of least squares. The results showed that, except for the third molars, the development of permanent teeth in Korean children was more advanced in females. The Demirjian's stage G of the second molar appeared last in both male and female subjects by age 18, showing 95th percentile at age in the male and female subjects between 16.7-17.4 years and 17.1-17.3 years, respectively. Coefficients of determination (r(2)) of the Demirjian's stages relative to age in regression analysis were 0.9721 in male and 0.9740 in female subjects. The standard error was 0.63 years in male and 0.62 years in female subjects. The estimated age according to regression analysis was within +/-1.0 year of the actual age in 92.0% of male and 92.5% of female subjects. Collectively, the data of the present study can be used as a reference for dental maturity and a standard for age estimation of Korean children.     

Comparison of dental maturity in children of different ethnic origins: international maturity curves for clinicians

Dental maturity was studied with 9577 dental panoramic tomograms of healthy subjects from 8 countries, aged between 2 and 25 years of age. Demirjian's method based on 7 teeth was used for determining dental maturity scores, establishing gender-specific tables of maturity scores and development graphs. The aim of this study was to give dental maturity standards when the ethnic origin is unknown and to compare the efficiency and applicability of this method to forensic sciences and dental clinicians. The second aim was to compare the dental maturity of these different populations. We noted an high efficiency for International Demirjian's method at 99% CI (0.85% of misclassified and a mean accuracy between 2 to 18 years +/- 2.15 years), which makes it useful for forensic purposes. Nevertheless, this international method is less accurate than Demirjian's method developed for a specific country, because of the inter-ethnic variability obtained by the addition of 8 countries in the dental database. There are inter-ethnic differences classified in three major groups. Australians have the fastest dental maturation and Koreans have the slowest.