Age estimation of unaccompanied minors. Part II. Dental aspects

Recent years have brought a worldwide increase in cross-border migration due to a globalized economy and ongoing belligerent conflicts. As a result, the percentage of foreigners among the general population has steadily increased not only in Germany, but also in other countries. This trend has triggered a growing demand for forensic medicine to assess the age of adolescents and young adults. The individuals examined here are unaccompanied minors without valid identification documents who do not know their age or else are suspected of not giving their correct age. The mineralization of third molars is the main criterion for dental age estimation of living subjects in the relevant age group. To date insufficient knowledge has been obtained about how ethnic origin can influence tooth mineralization. This, however, constitutes a restraint on the reliability of age estimates and hence on the forensic value of information essential to legal security. A comparative study was conducted to present comparative data on third molar mineralization in a Caucasoid, Mongoloid and African sample. In conclusion, forensic age estimates of living subjects would be more powerful tools if population-specific standards were applied to evaluations of wisdom tooth mineralization. Since the mineralization of third molars is usually completed by the age of 19 or 20 years, this feature cannot be used to ascertain whether a person has attained the forensically relevant age of 21 years. The question was whether determination based on an orthopantomogram of a combination of features relevant to dental age estimation of adults supplies forensically useful information for ascertaining whether a person has attained 21 years of age. The features considered include the DMFT index of all permanent teeth, the DMFT index of all permanent teeth excluding third molars and the DFT index of third molars projecting beyond the occlusal plane. It can be concluded that an evaluation of the variations of the DMFT index does not by itself yield sufficient data to determine with the accuracy required in criminal proceedings whether a person has attained 21 years of age. An additional X-ray examination of the medial clavicular epiphyseal cartilage is, therefore, strongly recommended when assessing whether a person is over 21.     

Age estimation from root development of mandibular third molars in comparison with skeletal age of wrist joint

Identification of the living person and the dead is of paramount importance for variety of reasons in forensic practice routinely. Age estimation is one of the prime factors employed to establish identity. Estimating age from teeth is generally reliable as they are naturally preserved long after all the tissues and even bones have disintegrated. A study was done to determine the age by root developmental changes, using the intraoral periapical radiographs of the mandibular third molars, adopting the Leif Kullman et al method. Three hundred forty-six girls and 389 boys of the age range 15-25 years, among the South Indian population of young adults from various schools and colleges in the vicinity of Dakshina Kannada and Udupi Districts and also among the patients visiting the outpatient department of Oral Medicine and Radiology, College of Dental Surgery, Manipal, were considered for this study. The subjects were roentgenographically examined to determine the age from the 7 stages of root development of the left mandibular third molar. Depending on the exact stage of root development as seen in the radiograph, the chronologic age was determined. This method sheds a new light on determining the ages of 15, 16, and 18 years, which has an immense medicolegal bearing.     

Prosthetic restorations, dental root fillings and periodontal bone resorptions as a forensic-odontologic aid for determining the age above 18 years: A radiographic study of orthopantomograms from a group of teenagers and yount adults

The human teeth are a valuable source of information concerning identification and age calculation in forensic sciences. Dental treatment often causes permanent alteration of the teeth, which is visible on radiographs. The correlation of prosthetic restorations, root canal fillings and periodontal bone loss with chronological age has not yet been used for determining the completed 18th year of life in teenagers and young adults, e. g. for legal and anthropological purposes. The aim of this study was to determine whether the evaluation of such findings on radiographs correlates with the chronological age in teenagers and young adults. MATERIAL AND METHODS: The dental X-rays (orthopantomogram, OPG) of 1053 outpatients (age: 14 to 24 years) were avaluated. The values "prosthetically restored", "filled dental root", or "periodontal bone loss" were recorded for each tooth present. The data were then evaluated using statistical tools. RESULTS: The correlation between the number of prosthetically restored teeth and the chronological age is high. The positive predictive value of determining an age of at least 18 years proved to be very high. However, these findings are rarely present in this age group. The number of endodontically treated teeth correlated less exactly with age. On the other hand, the determination of periodontal bone loss gave reasonable positive predictive values for the threshold value "chronological age of 18 years or more". DISCUSSION: This study provides for the first time predictive values for the estimation whether a person is 18 years of age, based on the evaluation of teeth with prosthetic restorations, root canal fillings or periodontal bone loss on OPGs only. Whereas the number of patients with such findings is generally low in this age group, some of the positive findings can be used for age estimation as an adjunct to other sources of age calculation. The sole application of these criteria is not recommended, as sanitary conditions of the teeth depend on both social and individual circumstances. Therefore, the calculated values also reflect the culture of the sample studied. Finally, they are time-dependent and have to be compared to data from other populations. These results have some bearing on the field of forensic odontology.     

Sexual Dimorphism of the Arm Bones in a Modern Greek Population

Abstract: Several studies have shown that sex determination methods based on measurements of the skeleton are population specific. Metric traits of the long bones of the arm have been reported as reliable indicators of sex. This study was designed to determine whether the three long bones of the arm can be used for sex determination on a skeletal population from Greece. The material used consists of the arm bones of 204 adult individuals (111 males and 93 females) coming from the Modern Human Skeletal Collection of the University of Athens. The age range is 19–96 years for males and 20–99 years for females. The maximum lengths and epiphyseal widths were measured in the long bones of the arm (humerus, radius, and ulna). The discriminant analysis of the metrical data of each long bone gave very high discrimination accuracies. The rate of correct sex discrimination based on different long bones ranges from 90.30% (ulna) to 95.70% (humerus). In addition, intra‐ and inter‐observer error tests were performed. These indicated that replication of measurements was satisfactory for the same observer over time and between observers. The results of this study show that metric characteristics of the arm bones can be used for the determination of sex in skeletal remains from Greece and that bone dimensions are population specific.     

Dead weight: Validation of mass regression equations on experimentally burned skeletal remains to assess skeleton completeness

In very fragmentary remains, the thorough inventory of skeletal elements is often impossible to accomplish. Mass has been used instead to assess the completeness of the skeleton. Two different mass-based methods of assessing skeleton completeness were tested on a sample of experimentally burned skeletons with the objective of determining which of them is more reliable. The first method was based on a simple comparison of the mass of each individual skeleton with previously published mass references. The second method was based on mass linear regressions from individual bones to estimate complete skeleton mass. The clavicle, humerus, femur, patella, metacarpal, metatarsal and tarsal bones were used. The sample was composed of 20 experimentally burned skeletons from 10 males and 10 females with ages-at-death between 68 and 90 years old. Results demonstrated that the regression approach is more objective and more reliable than the reference comparison approach even though not all bones provided satisfactory estimations of the complete skeleton mass. The femur, humerus and patella provided the best performances among the individual bones. The estimations based on the latter had root mean squared errors (RMSE) smaller than 300 g. Results demonstrated that the regression approach is quite promising although the patella was the only reasonable predictor expected to survive sufficiently intact to a burning event at high temperatures. The mass comparison approach has the advantage of not depending on the preservation of individual bones. Whenever bones are intact though, the application of mass regressions should be preferentially used because it is less subjective.     

Different skeletal elements as a source of DNA for genetic identification of Second World War victims

To this day process of identification of missing persons from skeletonized human remains with help of forensic genetics proves to be complex and challenging. The success rate of genetic identification in bones strongly depends on a combination of various factors, most importantly environmental factors and post-mortem interval. Furthermore, there are individual-specific factors that affect DNA preservation, such as race, gender, age and type of skeletal elements. The goal of our study was to optimize sampling process through determining which skeletal elements are superior in their preservation of DNA in 70-yearold skeletons belonging to victims of Second World War. We sampled different types of bones and teeth from three such skeletons found in Slovenian hidden mass grave Huda jama, 56 elements from each respective skeleton, together 168 elements. With the help of parameters, such as quantity of DNA, degradation rate and typing success, we tried to find the best types of elements to identify the victims. Prior to powdering bones and teeth, we removed contaminants. We decalcified 0.5 g bone and tooth powder followed by extraction and purification of DNA using Biorobot EZ1 (Qiagen). Quantification of obtained nuclear DNA was carried out using PowerQuant kit (Promega) and autosomal STR typing using ESSplex SE QS kit (Qiagen). Best parameters to assess skeletal elements that are superior in their DNA preservation were quantity of DNA and number of successfully typed STR loci. Metacarpal and metatarsal bones proved to be the best, followed by intermediate cuneiform, first distal foot phalanx, talus, petrous bone and tibia. We also created elimination database for persons involved in exhumation, anthropological and genetic analyses and exclude potential contamination.     

青少年骨龄鉴定及其相关问题

本文综述了骨龄研究和应用历史,以及骨龄评测的新方法和新技术,讨论了骨骼发育的影响因素、骨龄标准时效性、骨龄评测部位选择及法医骨龄鉴定等相关问题。     

Amyloid inclusions in choroid plexus epithelial cells. A simple autopsy method to rapidly obtain information on the age of an unknown dead person

Different methods such as X-ray examination of the skeleton and inspection of the teeth have been described for estimation of the age of an unidentified dead person. These methods are more or less exact but the results will not be available until many days after the autopsy. In the present paper, we present a fairly simple method to obtain information on the age of a deceased using amyloid inclusions in the choroid plexus epithelial cells.     

Forearm bones and sexual variation in Turkish population

Forensic anthropologists are aware that there are considerable differences between human populations and therefore develop study models for each skeletal population. The purpose of this study was to analyze forearm bones obtained from forensic settings in Turkey. The sample consists of 42 males and 38 females with an average age of 40 and 36 years, respectively. Numerous measurements were taken from the radius and ulna including lengths (in millimeters), midshaft diameters, and epiphyseal breadths (0.01 mm). Individuals with any anomaly and pathology were not included in the investigation. A stepwise analysis, when applied to individual bones, selected only length and midshaft transverse dimension in the radius and length only in the ulna. When the length was excluded from the statistic, head diameter and distal breadth of the radius and distal minimum head and midshaft anteroposterior diameters of the ulna provided the best predicting functions. Classification results were 92% for the radius and 91% for the ulna. For the incomplete bones, the accuracy rates were about 92% and 83%, respectively. In conclusion, a sex determination was made, in different rates of accuracy, in the human skeleton. Correct assessment can vary among populations. Dimorphism in our region forearm bones is greater than American whites. This supported the hypothesis that human variation is diverse, and population difference should be taken into account when osteometric standards are applied to others. Further studies are needed to understand why the forearm is more dimorphic in Turks.     

Preliminary results of an investigation on postmortem variations in human skeletal mass of buried bones

Extreme fragmentation can complicate the inventory of human skeletal remains. In such cases, skeletal mass can provide information regarding skeleton completeness and the minimum number of individuals. For that purpose, several references for skeletal mass can be used to establish comparisons and draw inferences regarding those parameters. However, little is known about the feasibility of establishing comparisons between inherently different materials, as is the case of curated reference skeletal collections and human remains recovered from forensic and archaeological settings. The objective of this paper was to investigate the effect of inhumation, weather and heat exposure on the skeletal mass of two different bone types. This was investigated on a sample of 30 human bone fragments (14 trabecular bones and 16 compact bones) that was experimentally buried for two years after being submitted to one of four different heat treatments (left unburned; 500?°C; 900?°C; 1000?°C). Bones were exhumed periodically to assess time-related mass variation. Skeletal mass varied substantially, decreasing and increasing in accordance to the interchanging dry and wet seasons. However, trends were not the same for the two bone types and the four temperature thresholds. The reason for this appears to be related to water absorption and to the differential heat-induced changes in bone microporosity, volume, and composition. Our results suggest that mass comparisons against published references should be performed only after the skeletal remains have been preemptively dried from exogenous water.     

Skeletal height reconstruction from measurements of the skull in indigenous South Africans

Stature reconstruction is important as it provides a forensic anthropological estimate of the height of a person in the living state; playing a vital role in the identification of individuals from their skeletal remains. Regression formulae for stature estimation have been generated for indigenous South Africans based on measurements of long bones of upper and lower extremities and the calcaneus. Since these bones are not always available for forensic analysis, it became necessary to use other bones such as the skull for stature estimation. The aim of the present study was to investigate the usefulness of certain measurements of the skull of indigenous South Africans in the estimation of adult stature. Ninety-nine complete skeletons obtained from the Raymond A. Dart Collection, School of Anatomical Sciences of the University of the Witwatersrand, were used. Total skeletal height (TSH) was calculated for each skeleton using the Fully's (anatomical) method. Furthermore, six variables were measured on each skull. TSH was regressed onto these cranial measurements in order to obtain regression formulae. The correlation coefficients obtained ranged between 0.40 and 0.54. The range of the standard errors of estimate from the current study (4.37 and 6.24) is high in comparison to that obtained for stature estimation based on intact long bones and the calcaneus. Therefore, the equations presented in this study should be used with caution in forensic cases when only the skull is available for human identification.     

14岁青少年骨发育的变化趋势

目的描述当前我国14岁青少年手腕骨发育特征,并初步评估14岁的青少年骨发育的变化趋势。方法以湖南娄底地区14岁青少年为对象(男53人,女56人),拍摄左手腕部X线片,参照顾氏图谱法描述各选定观察部位并分析发育特征,将统计结果与顾氏图谱法14岁骨龄标准进行比较分析。结果与顾氏法相比,男生组桡骨远端、第1掌骨近端和近节第4指骨骨骺发育程度较高,而女生组桡骨远端、第2～5掌骨、第1～5近节指骨和第2～5中节指骨骨骺发育程度较高。结论当前我国14岁青少年骨发育存在提前趋势,在女生组尤为显著。14岁是刑事责任年龄点之一,法医推断该年龄时应注意该特征对推断结果的影响。     

Analysis of artificial radiocarbon in different skeletal and dental tissue types to evaluate date of death

Radiocarbon dating, with special reference to the modern bomb-curve, can provide useful information to elucidate the date of death of skeletonized human remains. Interpretation can be enhanced with analysis of different types of tissues within a single skeleton because of the known variability of formation times and remodeling rates. Analysis of radiocarbon content of teeth, especially the enamel in tooth crowns, provides information about the date of formation in the childhood years and in consideration of the known timing of tooth formation can be used to estimate the birth date after 1950 ad. Radiocarbon analysis of modern cortical and trabecular bone samples from the same skeleton may allow proper placement on the pre-1963 or post-1963 sides of the bomb-curve as most trabecular bone generally undergoes more rapid remodeling than does most cortical bone. Pre-1963 bone formation would produce higher radiocarbon values for most trabecular bone than for most cortical bone. This relationship is reversed for formation after 1963. Radiocarbon analysis was conducted in this study on dental, cortical, and trabecular bone samples from two adult individuals of known birth (1925 and 1926) and death dates (1995 and 1959). As expected, the dental results correspond to prebomb-curve values reflecting conditions during the childhoods of the individuals. The radiocarbon content of most bone samples reflected the higher modern bomb-curve values. Within the bone sample analyses, the values of the trabecular bone were higher than those of cortical bone and supported the known placement on the pre-1963 side of the bomb-curve.     

Applicability of elemental composition of bone and dental tissue for human identification

The authors give the information about elemental composition (levels and concentration ranges of chemical elements) of human bone and dental tissue in the range from sodium to uranium, compare elemental composition of bones and teeth, make conclusion about applicability of bone and dental tissue for of human attribute diagnostics.     

Immunohistochemical proof of amelogenin in teeth--a contribution to the evaluation of the age in the identification of unknown corpses

When a corpse is found that cannot be identified, one of the forensic tasks is to determine how old the person was when she or he died. To solve this frequently asked question in forensic practice, the enamel protein amelogenin was marked immunohistochemically in 249 extracted teeth. Amelogenin is already produced during prenatal development and is gradually used up throughout life into old age. Hence, the demonstrability decreases with age. The extent of the labelling can be quantified by measuring the mean optical density (MOD). While it is not possible to determine the age on the basis of the mean optical density measurements alone, logistic regression of the MOD together with dichotomisation of the teeth according to age allows statements as to whether the person was younger or older than 30 years.     

2种陈旧骨骼、牙齿DNA纯化方法的比较

目的比较有机法+QIAquick纯化法和DNA IQ磁珠法对陈旧骨骼和牙齿DNA的纯化效果。方法选择10份陈旧骨骼和12份牙齿样本,进行消化后分别采用有机法+QIAquick纯化法和DNA IQ磁珠法进行提取纯化,进行DNA定量后用SinofilerTM试剂盒进行检测。结果 2种方法纯化的骨骼、牙齿DNA的IPC CT值无显著差异。有机法+QIAquick纯化法纯化的骨骼、牙齿DNA平均浓度分别为0.180ng/μL±0.068ng/μL和0.132ng/μL±0.027ng/μL,所有样品均获得全部基因分型。DNA IQ磁珠法纯化的DNA平均浓度分别为0.038ng/μL±0.028ng/μL和0.036ng/μL±0.007ng/μL,有5份骨骼和6份牙齿样本仅获得部分基因分型或未能分型。结论有机法+QIAquick纯化法对陈旧骨骼、牙齿DNA的纯化效果优于DNA IQ磁珠法。     

基于X线的活体骨骼年龄评定方法及其他技术

国内外通常利用X线片观察骨骼继发性骨化中心的出现和骨骺闭合程度的影像学特征来推断年龄。其中较常用的方法有计数法、计测法、图谱法、评分法及计算机辅助评定骨龄法等。目前国外普遍采用TW评分法。国内也有该评分法的应用报道。主要应用于体育和儿科临床实践中。法医临床学实践中常用六大关节判别方程法推断骨龄和活体年龄推断。其他还有利用牙齿内天冬氨酸的消旋化、骨密度检测以及端粒末端DNA片段长度的变化等年龄推断方法。     

Radiologically determined DMF index variations for forensic age estimation of young adults

The eruption and mineralization of third molars are the main criteria for dental age estimation of living people involved in criminal proceedings. Since the development of third molars is usually completed by the age of 19 or 20 years, this feature cannot be used to ascertain whether a person has attained the forensically relevant age of 21 years. This study examined whether the DMFT index or the third molar DFT index could supply reliable information enabling conclusions to be drawn about whether a person has reached the age of 21. To this end, 650 conventional orthopantomograms of German subjects aged 18 to 30 years were evaluated. The DMF index variations considered were found to be unsuitable for determining whether a person is over 21 because they displayed a weak correlation with age and considerable individual scatter. A high indicative value can only be attributed to a third molar DFT index of 4, although this is rarely observed in the relevant age group. An X-ray examination of the medial clavicular epiphyseal cartilage is, therefore, strongly recommended when assessing whether a person has attained 21 years of age.     

Estimation of age from epiphyseal union at the wrist and ankle joints in the capital city of India

Various studies conducted in and outside India for estimation of age from long bone joints revealed that unlike other vital parameters no uniform pattern exists for epiphyseal union of long bones in different countries of the world and also in different parts of the same country. A radiological study was conducted in 180 boys and girls of the capital city of India, Delhi, between the age group of 14-20 years to find out the age at which epiphyseal union at wrist and ankle joint takes place. The result of the study showed that the wrist joint epiphyseal union is completed in all cases in the age group of 19-20 years in males and 18-19 years in females. In the ankle joint, 17-18 years was the age group in males and 16-17 years the age group in females which showed complete epiphyseal union in all cases.