Studying survivors of near-lethal suicide attempts as a proxy for completed suicide in prisons

Sex determination is a necessary step in the investigation of unidentified human remains from a forensic context. Teeth, as one of the strongest tissues in the human body, can be used for this purpose. Most studies of sexual dimorphism in teeth are based on the traditional mesiodistal and buccolingual crown measurements. The purpose of this study is to examine the degree of sexual dimorphism in permanent molars of modern Greeks using crown and cervical diagonal diameters, and to evaluate their applicability in sex determination. A total of 344 permanent molars in 107 individuals (53 male and 54 female) from the Athens Collection were examined. Crown and cervical diagonal diameters of both maxillary and mandibular molars were measured. It was found that males have larger molars than females and in 19 out of 24 dimensions measured male molars exceeded female molars significantly (P<0.05). The most dimorphic molars are the maxillary second molar, and the mandibular second and first molars. Although other molars were also sexually dimorphic they did not have a statistically significant difference in all dimensions. Cervical diagonal diameters have found to be more sexually diamorphic than crown diagonal diameters. In discriminant function analysis the variables entered more frequently were the cervical diagonal diameters mainly of mandibular molars. Classification accuracy was found to be 93% for the total sample, 77.4% for upper jaw, and 88.4% for the lower jaw. Accuracy rates were higher for cervical than crown diagonal diameters. The data generated from the present study suggest that this metric method can be useful and reliable for sex determination, especially when the traditional dental measurements are not applicable.     

The third molar as an age marker in adolescents: new approach to age evaluation

Adolescence is a relatively short period between childhood and adulthood. It is very difficult to determine adulthood based on biological indicators. The third molar may be considered a potential age marker for the period between the ages of 16–21. Our study evaluated a set of 1700 panoramic radiographs of individuals aged between 5 and 21 years. Results confirmed the statistically significant difference in the course of third molars development. The mean deviation for individuals with one third molar agenesis is ?0.98 years, for individuals with two third molars agenesis ?1.89 years, and with three molars agenesis ?3.28 years. Thus, the extent of the deviation is directly proportional to the number of unformed third molars. The calculation of age according to the mean of stages of all third molars could lead to the underestimation of age. No intergender differences were found. Age determination using third molars could be used for forensic purposes.     

Dental age estimation and third molars: a preliminary study

The aim of the present investigation was to reconstruct the chronological age based on the dental developmental stages of third molars evaluated on orthopantomograms. A total of 1175 orthopantomograms were assembled from patients of Caucasian origin between 16 and 22 years of age. Each third molar present was scored by two observers according to a 10-stage developmental scale. The kappa statistics measured the intra- and inter-observer reliability. The general statistical analysis was based on multiple regression analysis in order to obtain multiple regression formulas for dental age estimation based on the number of third molars present on the evaluated orthopantomogram. No regression models were statistically significant when there was only one-third molar present because of the relatively small number of orthopantomograms that fitted this criterion. A strong agreement was found between the intra- and inter-observer measurements. The statistical analysis revealed both for males and females high Pearson correlation coefficients between contralateral third molars and smaller coefficients between antimeres. The obtained multiple regression formulas are only applicable in certain specified conditions, for instance when four third molars are present the following formulas should be used in a Caucasian male "age=10.2000+0.5122UL+0.5273LL" (developmental stage of upper and lower left third molars) or in case of a female "age=13.6206+0.1933UR+0.5080LR" (developmental stage of upper and lower right third molars). This investigation revealed that the chronological age of a Caucasian individual may be estimated based on regression formulas with a S.D. of 1.52 or 1.56 years for males and females, respectively, when all four third molars are present.     

A Retrospective Review of Forensic Odontology Reports Written by the Joint POW/MIA Accounting Command Central Identification Laboratory for Remains Identified from the Korean War

As of August 2014, the Joint POW/MIA Accounting Command has identified the remains of 1980 previously unknown U.S. service members; 280 were from the Korean War. To determine the accuracy and completeness of the available antemortem (AM) dental records, a review of the AM/postmortem (AM/PM) dental record comparisons from 233 Forensic Odontology Reports written in support of remains identified from the Korean War was performed. Seventy‐two AM/PM comparisons resulted in exact dental chartings while 161 contained discrepancies which were explainable. Explainable discrepancies include undocumented treatment (103), incorrectly charted third molars as missing (82), differing opinions of specific molars present/missing (20), and erroneous treatment documentation and/or misidentification of teeth present/missing (22, other than molars). Reassessment has revealed varying levels of completeness for our available AM dental records, the need to thoroughly review our computerized comparisons, adjust our comparisons to include molar pattern variations/third molars, and updating our database comparison program.     

Radiographic evaluation of third molar development in Spanish children and young people

Third molar development was evaluated in 786 young people aged between 4 and 20 years, all patients at the School of Dentistry of the University of Granada. The development of third molars and of mandibular second premolars and second molars was determined according to the stages proposed by Nolla. The onset of mandibular third molar formation was observed at very variable ages in this series, ranging from 5.86 to 14.66 years. The first developmental stages of maxillary third molars are not usually visible radiographically, which can lead to an incorrect diagnosis of agenesis. We found no significant relationship between the gender or age of the patient and the presence or absence of third molars. However, the presence/absence of the third molar can be predicted in 82.82% of cases when there is some degree of calcification of mandibular second molars and second premolars.     

Dental age estimation from the developmental stage of the third molars in western Chinese population

The purpose of this study is to provide reference data about estimating dental age from third molars of the western Chinese population for comparing with other populations and being applied to the age estimation of western Chinese juveniles and adolescents. A total of 2078 digital panoramic radiographs of 989 male and 1089 female Chinese subjects aged between 5 and 23 years were examined. The mineralization status of the third molars was assessed using the formation stages described by Demirjian et al. with two modifications. The results showed that the development of third molars in the western Chinese population was likely to begin at age 5 in both males and females. The third molars 28 and 48 showed significantly higher frequency in females than in males. The third molars 18 in the stage 1, 38 in the stages 1, A and G, and 48 in the stage H showed significantly older average age in females than in males. The Demirjian's stages C and D could be used as a reference stage to determine dichotomously whether a western Chinese is more likely to be under or above age 14 or 16, respectively. This study provided reference data for the age estimation of western Chinese juveniles and adolescents by the mineralization stages of the third molar. Apart from forensic age determination in living subjects, the presented reference data can also be used for age estimations of unidentified corpses and skeletons.     

The chronology of third molar mineralization in the Austrian population--a contribution to forensic age estimation

The aim of the present study was to determine the chronology of third molar mineralization and to establish Austrian reference data. Therefore, a cross-sectional study was undertaken by evaluating 610 panoramic radiographs in order to assess the mineralization status of the mandibular third molars of Austrian male and female individuals (275 males and 335 females) between the ages of 12 and 24. The evaluation was carried out using the eight grade scheme of Demirjian et al. (1973). Mean ages, standard deviations, standard errors and percentile distributions are presented for each stage of development. Significant differences between the left and right mandibular third molars were not found. Males reach the developmental stages earlier than females, statistically significant differences were noted in stages E and F. Both mandibular third molars were observed in the majority of the individuals of the Austrian sample (477 individuals, 78.2%). For medicolegal purposes the likelihood of whether an Austrian individual is older than 18 years or not was determined.     

Reliability of Third Molar Development for Age Estimation in a Texas Hispanic Population: A Comparison Study*

Abstract: Evaluating third molars from 950 Hispanic individuals aged 12–22 years using Demirjian’s schematic for crown and root formation found that Hispanic third molar development was 8–18 months faster than American Caucasians as reported by Mincer, Harris and Berryman in 1993. This represents a statistically significant increase. Earlier development was more apparent in the later stages F through H. Hispanic males reach developmental stages faster than Hispanic females and maxillary third molars reach developmental stages faster than mandibular third molars in both sexes. The earliest age observed for stages B–H (e.g., Stage H first observed at age 13.92 years in females) and the oldest age observed for Stages B–G were developed to facilitate age prediction of unknown individuals. Prediction tables for minimum and maximum age for an observed stage (e.g., if a female maxillary third molar is stage F it means she is older than 13 years) for each sex‐jaw group were calculated.     

Preliminary report on a new method of human age estimation from single adult teeth.

A total of 317 upper and lower third molars were randomly divided into working and control samples and used to estimate chronological age employing a method which combined multiple regression analysis of data from Gustafson's and Maples's scoring system, direct morphological measurements obtained with a Kontron image analysis system and logarithmic data transformation. The standard errors of estimate were 2.4-6.8 years in the working sample and 1.9-7.5 years when the derived formulae were tested on the control sample, respectively. Compared to previous studies, this method provides a smaller standard error of estimate from a single molar tooth. The method is presently being tested on other tooth categories, like premolars, canines and other types of molars.     

Comparative Analysis of the Effects of Heat on the PCR‐Amplification of Various Sized DNA Fragments Extracted from Sus Scrofa Molars*

Abstract: This study examined the effects of heat on the amplification of DNA from the dental pulp of Sus scrofa molars and investigated the protection afforded to the pulp tissue by the dental enamel, alveolar process, and soft tissue of the head. Segments of defleshed maxilla and mandible encasing the first molar (n = 60) were subject to a range of temperatures for 15 min. Dental pulps were retrieved. Amplifications using three‐primer and four‐primer multiplexes showed no degradation of the largest fragment following exposure to 450°C. Amplifications in the three‐primer multiplex (283 bp) were successful following exposure to 525°C in maxillary samples only. This study revealed the enamel density of maxillary molars to be greater than mandibular molars in Sus scrofa. Following incineration of intact heads for 15 min (n = 10) and 1 h (n = 4) at an average temperature of 625°C, amplifications of the largest fragment (450 bp) were successful from both maxillary and mandibular teeth.     

第三磨牙萌出情况调查研究

目的为满足应用牙齿萌出时间推测年龄的需要。方法采用帕尔曼牙位标志法记录,对1582名16-23岁学生进行调查。结果随着年龄的增加,4枚第三磨牙均末萌出的呈递减状态,而4枚均萌出的则呈递增状态。萌出1枚的为10.11%,萌出2枚的为13.27%,萌出3枚的为7.96%,萌出4枚为18.90%,4枚均未萌出的为49.75%。结论本组调查数据填补了有关资料的不足,为法医学推测年龄提供参考资料。     

Dental Age Estimation: A Test of the Reliability of Correctly Identifying a Subject Over 18 Years of Age Using the Gold Standard of Chronological Age as the Comparator

This study was designed to test the reliability of using the third molars to demarcate between child and adult status. A total of 2000 dental panoramic tomographs were used for assessment of the calculated age using the 8‐stage system of tooth development and applied to all four third molars. The LL8 was also assessed using this 8‐stage system. For each tooth development stage, the Normal distribution and percentile summary data were estimated. The calculated dental age compared with the chronological age was statistically significantly different (p < 0.001) for both females and males giving underestimates of the true age. Comparison of single tooth dental age and chronological age was only slightly different. The most important finding is that the assignment to above or below the 18‐year threshold, in the age range 17 years to 19 years, could be wrong on up to 50% of occasions.     

Reproducibility of radiographic stage assessment of third molars

The aim of this study was to determine intra- and inter-observer variability of the developing third molar from panoramic radiographs. Formation of third molars was assessed according to stages described by modified Demirjian et al.'s methods: Moorrees et al. [C.F.A. Moorrees, E.A. Fanning, E.E. Hunt, Age variation of formation stages for ten permanent teeth, J. Dent. Res. 42 (1963) 1490-1502] and Solari and Abramovitch [A.C. Solari, K. Abramovitch, The accuracy and precision of third molar development as an indicator of chronological age in Hispanics, J. Forensic Sci. 47 (2002) 531-535]; in addition, data were also analysed unmodified, i.e. Haavikko [K. Haavikko, The formation and alveolar and clinical eruption of the permanent teeth, an orthopantomograph study, Proc. Finn. Dent. Soc. 66 (1970) 104-170] and Demirjian et al. [A. Demirjian, H. Goldstein, J.M. Tanner, A new system of dental age assessment, Hum. Biol. 45 (1973) 211-227]. The sample was a random selection of 73 panoramic radiographs from patients aged 8-24 years. After training, the left maxillary and mandibular third molars were scored on two separate occasions without knowledge of previous scores. Cohen's Kappa and percentage agreement were calculated for each method, for maxillary, for mandibular third molars and combined. Percentage agreement for stages was also calculated. Intra-observer agreement was greater for mandibular third molars compared to maxillary third molars, and better for methods with fewer stages. Kappa values indicated good agreement for most methods; the best was Demirjian et al.'s method for mandibular third molar with very good agreement (K = 0.80) for the first author, good agreement for the second author (K = 0.75) and good agreement between observers (K = 0.75). The stages with best agreement were Demirjian's stage E [A. Demirjian, H. Goldstein, J.M. Tanner, A new system of dental age assessment, Hum. Biol. 45 (1973) 211-227] and Moorrees et al.'s stage Cc and R1/4 [C.F.A. Moorrees, E.A. Fanning, E.E. Hunt, Age variation of formation stages for ten permanent teeth, J. Dent. Res. 42 (1963) 1490-1502]. CONCLUSIONS: Having clearly defined stages and fewer stages allowed better reproducibility of third molar formation.     

Accuracy of Identifying Juvenile/Adult Status from Third Molar Development using Prediction Probabilities Derived from Logistic Regression Analysis

The use of third molars in predicting juvenile/adult status (</≥ 18 years) has important legal ramifications. Third molar development was assessed using Köhler's grading on 268 orthopantomograms of Indian subjects. Logistic regression analysis was applied to determine allocation accuracy of juvenile/adult status and the level of probability that is “reliable” in predicting juvenile/adult status. Allocation accuracies ranged between 75.8% and 78.2% for the sexes combined, with minimal male‐female differences. Adults were categorized more accurately than juveniles, suggesting that Köhler's grading puts Indian juveniles at greater risk of unwarranted punishment. In both sexes, juvenile/adult status was “reliably” predicted when the probability was >80% using individual third molars (excepting the lower right third molar in males); combining upper and lower third molars on the left/right sides, “reliable” predictions were possible when the probability was >80% and >90% for females and males, respectively. Overall, “reliable” juvenile/adult status prediction was achieved in c. 36% of subjects.     

Comparative morphometric evaluation of permanent mandibular molar dentition of plain and hilly (Momba/Mongoloid) populations of eastern Indian states

Morphometric comparative field studies were conducted of the permanent molars of plain people of Eastern India and Momba/Mongoloid population of eastern-most hill people known as Momba and claimed as Mongoloid. The data obtained was found very useful to distinguish and identify the two great neighbouring Asian people comprising one third of the total World human population.     

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.     

Forensic human identification: Investigation into tooth morphotype and DNA extraction methods from teeth

When a body is decomposed, hard tissues such as teeth may provide the only DNA source for human identification. There is currently no consensus as to the best DNA extraction method, and there is a lack of empirical data regarding tooth morphotype and condition that may impact DNA recovery. Therefore, this study sought to investigate which variables significantly improved DNA concentration, integrity and profiling success. A total of 52 human teeth were assessed, representing all tooth morphotypes from three deceased individuals. DNA was extracted using both the QIAamp® DNA Investigator Kit and the phenol-chloroform method. DNA concentration and degradation index were assessed using real time PCR, prior to conventional DNA profiling. Contrary to international guidelines promoting the use of molars, DNA profiling from molars was the least successful, with premolars, followed by canines, performing the best. The presence of fillings reduced the DNA quantity and quality obtained and may explain the poor performance of molars. DNA from the maxillae were significantly less degraded when the QIAamp® was used, although this did not influence DNA profiling success. A significant increase in DNA concentration, integrity and profiling success was observed in diseased teeth (periodontitis) compared to those without disease. This may be due to increased white blood cell presence at the site. There was no significant difference in DNA profiling success between the two DNA extraction methods. However, different teeth yielded failed DNA profiles for each extraction method, suggesting that repeated attempts, using alternative DNA extraction methods, is recommended. The recovery of additional DNA profiling information from degraded samples may help to ultimately reduce the burden of unidentified human remains.     

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.     

Optimal Dental Age Estimation Practice in United Arab Emirates’ Children

The aim of the study was to detect whether the Willems model, developed on a Belgian reference sample, can be used for age estimations in United Arab Emirates (UAE) children. Furthermore, it was verified that if added third molars development information in children provided more accurate age predictions. On 1900 panoramic radiographs, the development of left mandibular permanent teeth (PT) and third molars (TM) was registered according the Demirjian and the Kohler technique, respectively. The PT data were used to verify the Willems model and to develop a UAE model and to verify it. Multiple regression models with PT, TM, and PT + TM scores as independent and age as dependent factor were developed. Comparing the verified Willems‐ and the UAE model revealed differences in mean error of ?0.01 year, mean absolute error of 0.01 year and root mean squared error of 0.90 year. Neglectable overall decrease in RMSE was detected combining PM and TM developmental information.     

The Reliability of Chronological Age Determination by Means of Mandibular Third Molar Development in Subjects in Croatia*

Abstract: The aim of this study was to determine the development of the mandibular third molar and its relation to chronological age. The evaluated material consisted of 979 orthopantomograms of patients of Croatian Caucasian origin aged between 5.7 and 14.6 years. Third molar developmental stages were evaluated according to the stages proposed by Nolla. The frequencies of different stages of mineralization and the mean value of the mineralization of the mandibular third molars with regard to age, gender, and size of the mandible were determined and the coefficient of correlation determined between the age of the subject and the stage of development of the mandibular molars. Statistically significant correlation was determined between mineralization of the mandibular third molar and chronological age of the subjects (boys, mandibular left third molar r = 0.779, right third molar r = 0.793; girls, mandibular left third molar r = 0.746, right third molar r = 0.725). It can be concluded that the accuracy of age estimation based on Nolla’s method is applicable for Croatian children.