根据牙齿磨耗度推断年龄的研究

有关牙齿磨耗度与年龄的关系,已有许多学者进行了研究。目前,如何缩小推断年龄误差和提高推断年龄的准确性,是法医工作者所瞩目的问题。在日本,竹井哲司应用数量化第I类理论、多元回归的方法及电子计算机技术,对牙齿磨耗度与年龄的关系进行了研究,得出了推断年龄方程。多元逐步回归的方法较多元回归法可筛选出较好的变量,得出最优回归方程,而用此法进行本     

基于Demirjian法推断年龄的研究进展

近年来,个体年龄推断在法医学实践中逐渐受到关注。常用的年龄推断方法主要是通过骨骼和牙齿发育。与骨骼相比,牙齿更为坚硬且不易受到外部环境影响,因此在年龄推断中具有重要作用。Demirjian法是评估牙龄最常用的方法之一,目前在多个国家得到了广泛应用。本文主要对Demirjian法在不同人群中应用的准确性进行回顾,发现与实际年龄相比,推断年龄大多存在高估现象,结合多位学者的研究结果分析认为,该情况可能与种族、地域、性别等差异具有相关性。     

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。     

中国黑龙江地区汉族未成年人的牙钙化程度及年龄推断

目的探讨未成年人牙齿钙化程度与其年龄的关系,建立根据牙齿钙化程度推断未成年人年龄的方法。方法拍摄黑龙江地区1510名未成年人（男737名,女773名,年龄6～15周岁）牙齿曲面断层影像片,利用计算机观察全口曲面断层影像片中下颌恒牙牙位处钙化程度的影像特征,并建立牙齿钙化分级评分标准,然后根据此标准对下颌牙齿进行分级评分;将其结果输入SPSS13.0软件统计,按α=0.05对牙齿钙化分值分性别分年龄段组进行非参数检验和与年龄的相关性分析,最终建立根据牙齿钙化程度推断年龄的回归方程。结果同名牙左右侧无差异（P〉0.05）,而性别间有差异（P〈0.05）;男女性下颌牙齿的钙化程度均与年龄高度相关（r〉0.7）;所建方程模型合理可靠,盲测结果显示推断年龄与实际年龄间无统计学差异,误差绝对值的平均值男性为（0.367±0.257）岁,女性为（0.367±0.245）岁。结论本研究中未成年人牙齿钙化程度随年龄的增长而呈现增高趋势,直至完全钙化;根据牙齿钙化程度建立的回归方程可用于未成年人活体以及无名尸体的年龄推断。     

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 ...     

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。     

Demirjian法在推断上海汉族青少年生活年龄中的应用

目的研究Demirjian法推断上海汉族青少年生活年龄的适用性。方法收集上海市第九人民医院符合纳入标准的年龄在11～20周岁的汉族青少年口腔曲面全景片501例．其中男性168例．女性333例。按照Demirjian法进行牙龄推断,并对生活年龄与Demirjian法推断的牙龄进行配对t检验：通过单因素数学模型探索两者之间的关系。结果直接应用Demirjian方法推断上海汉族青少年牙龄时．其推断的牙龄与实际生活年龄之间存在差异。通过建立牙龄推断的单因素数学模型。并将其推断的年龄与实际生活年龄进行配对t检验,结果显示男性12～16周岁（不含16周岁）、女性13～14周岁（不含14周岁）和15～17周岁（不合17周岁）年龄段无统计学意义（P〉0．05）,并且有81．04％的样本推断误差小于1岁。结论本研究有望成为推断上海地区汉族青少年生活年龄的有效方法,但不适合17周岁以上青少年人群。     

重庆地区汉族未成年人牙龄推断的研究

目的运用牙齿曲面断层影像技术,研究6周岁～15周岁重庆市未成年人牙齿钙化的规律,从而建立根据牙齿钙化程度推断年龄的方法。方法依据牙齿钙化分级标准对1321名（男性577名,女性744名）重庆市6周岁～15周岁未成年人牙齿曲面断层片上的牙齿钙化程度进行分级评分;将评分值与对应的性别和年龄分别输入SPSS13.0软件进行统计分析,最终建立推断年龄的方程。结果左右侧同名牙齿钙化程度无统计学差异（P〉0.05）,但性别间有统计学差异（P〈0.05）;下颌左右侧8颗牙齿的钙化程度与年龄相关系数均大于0.58;所建利用不同牙齿组合推断年龄的线性回归模型调整拟合优度均大于0.67,估计值标准误男性为0.95周岁～1.11周岁、女性为1.02周岁～1.12周岁。结论该方法可用于法庭科学领域中推断重庆市6周岁～15周岁未成年人活体以及尸体的年龄。     

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。     

陕西省6～15岁汉族未成年人牙龄的研究

目的运用全口曲面断层影像技术,研究陕西省6-15岁汉族未成年人牙齿钙化规律,建立利用牙齿钙化程度推断陕西汉族6-15岁未成年人年龄的方法。方法按照中国汉族儿童及青少年牙齿钙化分级标准,对1997名（男934名,女1063名）陕西省6-15岁汉族未成年人的全口曲面断层影像中下颌恒牙钙化程度进行分级评分;将所得评分值及对应的年龄输入SPSS软件并进行统计分析,最终建立年龄推断的方程。结果下颌同名牙钙化评分值侧别间非参数检验结果 P〉0.05,而性别间非参数独立样本检验结果 P〈0.05;下颌左侧各颗恒牙钙化程度与年龄相关分析结果 r〉0.59;方程拟合优度检验所得校正决定系数均大于0.76,估计值标准误男性在0.85-1.05岁之间、女性在0.83-0.97岁之间。结论本研究建立的方法合理可靠,可用于陕西省汉族6-15岁未成年人年龄的推断。     

Age estimation of Korean adults by occlusal tooth wear

The aim of the present study was to evaluate the validity of the modified Kim's scoring system as a practical method of recording occlusal tooth wear and estimating age. For this purpose, 1092 pairs of maxillary and mandibular full-arch casts were randomly selected, scored, and analyzed. The results showed that the modified Kim's scoring system had excellent reliability, and that occlusal tooth wear had a positive correlation with age. Tooth wear scores of all teeth except the two lower central incisors were higher in males than in females. Calculating tables for age estimation were designed by multiple linear regression analysis. Estimated ages were within +/-5 years of actual ages in 63.5% of male subjects, and 64.0% of female subjects. The accuracy of age estimation was increased when the subjects were divided into two age groups and data were re-analyzed. Collectively, it was shown that the modified Kim's scoring system is a reliable and accurate method for age estimation, and that the data from these 1092 individuals can be used as a standard for age estimation of Korean adults.     

A test of the differential accuracy of the maxillary versus the mandibular dentition in age estimations of immature skeletal remains based on developing tooth length

Liversidge and colleagues developed a method for predicting the age of immature skeletal remains based on the length of developing teeth. This quantitative method combines dental data from both jaws, except for the permanent lateral incisor, and because there are reasons to suspect that these two types of data are not identical and should not be combined, it raises concerns regarding the accuracy of the technique when applied differently to each jaw. In this study, the differential accuracy of the method was test when applied to the maxillary and mandibular dentition. The test sample is comprised of 57 Portuguese subadult skeletons of known age at death. Results suggest an overall high consistency between estimates obtained from both jaws, but for the permanent dentition only. In the deciduous dentition the age estimates obtained from the maxillary teeth tend to be greater than the age estimates obtained from the mandibular pair, and the differences are significant for the incisors and canine. Additionally, ages obtained from the maxillary deciduous canine also differ significantly from true chronological age. In the permanent dentition there were no differences between the ages provided by both jaws but both the maxillary and mandibular second molars show a significant tendency to underestimate true chronological age. Although this study cannot validate completely the method presented by Liversidge and colleagues, it does provide an important test to its accuracy and calls for further research into its overall performance, particularly with respect to the results obtained from both jaws.     

Accuracy of developing tooth length as an estimate of age in human skeletal remains: the deciduous dentition

Dental age assessments are widely used to estimate age of immature skeletal remains. Most methods have relied on fractional stages of tooth emergence and formation, particularly of the permanent dentition, for predicting the age of infants and very young children. In this study, the accuracy of regression equations of developing deciduous tooth length for age estimation (Liversidge et al.) is tested on a sample of 30 Portuguese subadult skeletons of known age at death. Overall the method shows high accuracy and the average difference between estimated and chronological age is between 0.20 and -0.14 years when using single teeth, and 0.06 years, when using all available teeth. However, there is a tendency for the deciduous molars to provide overestimates of chronological age. Results show that age estimates can be obtained within +/-0.10 years with a 95% confidence interval when several teeth are used. Overall between-tooth agreement in age estimates decreases with increasing age but there is less variability of estimates with more teeth contributing to overall mean age. One seemingly limitation of this method may be the fact that it was developed by combining the maxillary and mandibular teeth. The other is related to the accuracy with which radiographic tooth length can be used as a valid surrogate for actual tooth length. Nevertheless, the advantages of this metric method surpass the limitations of chronologies based on stages of dental development.     

上、下尖牙髓腔/牙体表面积比值的年龄判定价值研究

目的 通过三维重建测量上、下颌尖牙髓腔/牙体表面积比值(Pulp/Tooth area Ratio,PTR)来推断个体年龄,为临床年龄推断的应用提供科学依据.方法 收集口腔门诊患者年龄在16～65岁200例锥形束CT(Cone beam computed tomography,CBCT)影像资料,以4个尖牙为测量对象并...     

Relationship Between Pulp Tooth Area Ratio and Chronological Age Using Cone‐beam Computed Tomography Images

This study investigated the relationship between chronological age and pulp tooth area ratio (PTR) in maxillary central teeth using cone‐beam computed tomography (CBCT) images in the Turkish population. The sample consisted of CBCT images of 120 male and female subjects between 14 and 75 years old. The PTR of the maxillary central teeth was calculated using inVivo 5 software (Anatomage, San Jose, CA). Data were analyzed with independent t‐test and Pearson's rank correlation test. There was a significant negative correlation between chronological age and PTR (r = ?0.615). The results showed that the PTR of maxillary central teeth is a reliable method for age estimation in the Turkish population.     

The Effects of Racemization Rate for Age Estimation of Pink Teeth

Pink teeth is thought to result from the seepage of hemoglobin caused by dental pulp decomposition. We investigated whether racemization can be applied for age estimation in cases of pink teeth where the whole tooth is used. The pink teeth used were three cases and the normal teeth for control were five mandibular canines of known age. Age of the pink teeth was calculated on the basis of regression formula obtained from the five control teeth. Only a slight error was noted between the actual and estimated ages of the pink teeth (R² = 0.980, r = 0.990): Cases 1–3 actually aged 23, 53, and 59 years were estimated to be 26, 52, and 60 years. Based on our results of testing pink teeth of known age, we suggest that racemization techniques allow for the age estimation of pink teeth using the same methods for normally colored teeth.     

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。     

Accuracy of BR Regression Equation for Impacted Teeth in Age Estimation in Haryana Population of India

Abstract:  Dental cementum is a vital tissue that demonstrates continuous apposition throughout the life of a tooth. Positive correlation has been reported between the coronal displacement of cementum and age in impacted teeth and BR regression equation has been proposed. The present study is an attempt to calculate accuracy of BR regression equation in Haryana population of India. The study was conducted on 20 impacted mandibular third molars extracted from healthy patients, aged between 22 and 32 years. The bucco-lingual ground sections were prepared and the distance between the edges of enamel and cementum were measured with micrometer attached to a light microscope and BR regression equation was applied for age estimation. Although the estimated age with BR regression equation was less than chronological age it was not statistically significant. Hence, the BR regression equation can be used in medicolegal as well as in forensic odontology for age estimation.     

Dental age assessment: the applicability of Demirjian method in eastern Turkish children

In the literature, little is known about the applicability of this method in Turkish children. The aim of this study was, therefore, to evaluate the reliability of Demirjian method of age estimation when used for eastern Turkish children. A retrospective study was performed on a sample of panoramic radiographs taken from 807 healthy eastern Turkish children. The stages of dental maturity of the mandibular left seven permanent teeth for each subject using the eight radiographic dental maturity stages demonstrated by Demirjian were evaluated. A paired t-test was used for statistical analysis. The mean difference between the chronological and dental ages ranged from 0.2 to 1.9 years in girls and from 0.4 to 1.3 years in boys. The differences between the chronological and dental ages were statistically significant in all age groups. The applicability of Demirjian method is not suitable for eastern Turkish population.     

Age estimation by occlusal tooth wear

The purpose of the present investigation was to test the accuracy of a new scoring system in recording tooth wear for age estimation. The material consisted of dental stone casts of 383 volunteers who had sound premolars and molars with normal occlusion. The degree of occlusal wear for all premolar and molar teeth was scored with the new system. The high intra- and inter-examiner concordances showed that the new score system was very reliable. The degree of tooth wear showed a significant positive correlation with age in each and every examined tooth of both males and females. Tooth wear scores of males were higher than those of females. Calculating tables for age estimation were designed and the accuracy of age estimation was obtained with the General Linear Models procedures. Our system could provide estimation of an individual's age within +/-3 years in 42.4% of males and 49.4% of females, within +/-5 years in 61.8% of males and 63.3% of females. When the subjects were divided into two age groups and data were re-treated, the accuracy of age estimation was increased. Collectively, it was shown that our new system for scoring tooth wear is a reliable and accurate method for age estimation.