Forensic age diagnostics of living people undergoing criminal proceedings

Postmortem computed tomography assessment of skeletal and dental age in Polish children, adolescents, and young adults

This paper presents a retrospective analysis of postmortem computed tomography (PMCT) scans of secondary ossification centers in the medial clavicular epiphysis, iliac crest apophysis, proximal humeral epiphysis, distal femoral epiphysis, proximal tibial epiphysis, and distal tibial epiphysis. At the same time, we analyzed PMCT scans of the maxillary and mandibular incisors, canines, premolars, and molars. We assessed 203 corpses, whose age ranged from 2 to 30 years, including 156 males and 47 females. The purpose of our study was to compare the processes of secondary ossification center fusion and permanent tooth maturation. Our research hypothesis was that certain stages of skeletal and dental maturation occur along consistent timelines that can be related to the chronological age. Secondary ossification center fusion was evaluated based on Kreitner and also McKern and Steward's classifications. The process of permanent tooth maturation was evaluated with Demirjian's method. Spearman's correlation coefficients (Rho) were positive in all analyses, which indicates that epiphyseal fusion progresses with age. The strongest relationship between the age and the stages of ossification was observed in the proximal tibial epiphysis (p < 0.001; Rho = 0.93) in females and in the medial clavicular epiphysis (p < 0.001; Rho = 0.77) in males. Studies show the importance of concomitant analysis of skeletal and dental maturation with a subsequent comparison of the results to achieve a greater precision in age estimation. A comparison of the results obtained in the study population of Polish children, adolescents, and young adults with the results of other studies in populations of similar ages showed a number of similarities in the time windows of dental and skeletal maturation. These similarities may help in age estimation.

Decision tree analysis for age estimation in living individuals: integrating cervical and dental radiographic evaluations within a South African population

Age estimation in living individuals around the age of 18 years is medico-legally important in undocumented migrant cases and in countries like South Africa where many individuals are devoid of identification documents. Establishing whether an individual is younger than 18 years largely influences the legal procedure that should be followed in dealing with an undocumented individual. The aim of this study was to combine dental third molar and anterior inferior apophysis ossification data for purposes of age estimation, by applying a decision tree analysis. A sample comprising of 871 black South African individuals (n = 446 males, 425 = females) with ages ranging between 15 and 24 years was analyzed using panoramic and cephalometric radiographs. Variables related to the left upper and lower third molars and cervical vertebral ring apophysis ossification of C2, C3, and C4 vertebrae analyzed in previous studies were combined in a multifactorial approach. The data were analyzed using a pruned decision tree function for classification. Male and female groups were handled separately as a statistically significant difference was found between the sexes in the original studies. A test sample of 30 individuals was used to determine if this approach could be used with confidence in estimating age of living individuals. The outcomes obtained from the test sample indicated a close correlation between the actual ages (in years and months) and the predicted ages (in years only), demonstrating an average age difference of 0.47 years between the corresponding values. This method showed that the application of decision tree analysis using the combination of third molar and cervical vertebral development is usable and potentially valuable in this application.

Getting the chronological age out of DNA: using insights of age-dependent DNA methylation for forensic DNA applications

BACKGROUND

DNA analysis for forensic investigations has a long tradition with important developments and optimizations since its first application. Traditionally, short tandem repeats analysis has been the most powerful method for the identification of individuals. However, in addition, epigenetic changes, i.e., DNA methylation, came into focus of forensic DNA research. Chronological age prediction is one promising application to allow for narrowing the pool of possible individuals who caused a trace, as well as to support the identification of unknown bodies and for age verification of living individuals.

OBJECTIVE

This review aims to provide an overview of the current knowledge, possibilities, and (current) limitations about DNA methylation-based chronological age prediction with emphasis on forensic application.

METHODS

The development, implementation and application of age prediction tools requires a deep understanding about the biological background, the analysis methods, the age-dependent DNA methylation markers, as well as the mathematical models for age prediction and their evaluation. Furthermore, additional influences can have an impact. Therefore, the literature was evaluated in respect to these diverse topics.

CONCLUSION

The numerous research efforts in recent years have led to a rapid change in our understanding of the application of DNA methylation for chronological age prediction, which is now on the way to implementation and validation. Knowledge of the various aspects leads to a better understanding and allows a more informed interpretation of DNAm quantification results, as well as the obtained results by the age prediction tools.

Forensic age estimation in living children: how accurate is the Greulich-Pyle method in Sabah, East Malaysia?

Background

The Greulich and Pyle's Radiographic Atlas of Skeletal Development of the Hand and Wrist (GP Atlas) is the most widely used method of determining the bone age (BA) of a child. It is also a widely accepted method for forensic age determination. As there is limited local bone age data for forensic age estimation, the purpose of this study was to assess the accuracy of the GP Atlas for forensic age determination in living Sabahan children.

Method

This study recruited 182 children between the ages of 9 years to 18 years. BA estimation of the left-hand anteroposterior radiographs were performed by two experienced radiologists using the Greulich-Pyle method.

Results

The BA estimates from two radiologists had very high interobserver reliability (ICC 0.937) and a strong positive interobserver correlation (r > 0.90). The GP method, significantly and consistently underestimated chronological age (CA) by 0.7, 0.6 and 0.7 years in overall children, boys and girls respectively with minimal errors. Mean absolute error and root of mean squared error for overall children was 1.5 and 2.2 years respectively, while mean absolute percentage error was 11.6%. This underestimation was consistent across all age groups but was statistically significant only at 13-13.9 and 17-18.9 years old age groups.

Conclusion

Despite high interobserver reliability of BA estimation using the GP Atlas, this method consistently underestimates the age of the child in all children to a significant degree, for both boys and girls across all age groups, with an acceptably low level of error metrics. Our findings suggest that locally validated GP Atlas or other type of assessments (artificial intelligence or machine learning) are needed for assessment of BA to accurately predict CA, since current GP Atlas standards significantly underestimated chronological age with minimal error for children in Sabah. A larger population-based study would be necessary for establishing a validated atlas of a bone age in Malaysia.

Estimating the 18-Year Threshold with Third Molars Radiographs in the Southern Italy Population: Accuracy and Reproducibility of Demirjian Method

The estimation of the age of the majority of living subjects is widely required nowadays due to the presence of unidentifiable individuals, without documents and general information, involved in migration or legal procedures. Dental age estimation (DAE) is a valid method for investigating the age of subjects. The aim of this study was to evaluate the accuracy of the Demirjian method in a limited age group (16-24 years) in differentiating between older and younger than 18 years. From an initial sample of 17,594 radiographs, 460 were selected meeting the inclusion criteria. Two dentists provided the age estimate according to the Demirjian method, with a simplified approach based on the development of the third molars. The presence of a developmental stage of H for at least one third molar allowed to establish the major age if the other third molars, inferior or superior, have reached a stage equal or superior to F, with an accuracy of 90.2% and a predictive positive value of 91.6%. Thirty-three patients showed the development of at least one third molar (Stage H) before the age of 18 years while six patients showed the development of all four third molars with root completion (stage H) before the age of 18 years. When all third molars reached stage H an individual was over 18 years old in 97.4% of cases. In presence of one third molar on stage H and a stage equal or superior to F for the other third molars the probability of being of major age was 91.6%.

Accuracy of different dental age estimation methods for determining the legal majority of 18 years in the Turkish population

OBJECTIVES

Radiographic evaluation of the third molar maturation is used to estimate dental age, especially in adolescence. This study aimed to assess the application of three age estimation methods (Cameriere's third molar maturity index (I_3M), Demirjian's maturation stages, and The London Atlas) to determine whether an individual is 18 years or older (adult) or younger than 18 years (minor).

MATERIALS AND METHODS

The dental age was estimated using the I_3M, Demirjian's maturation stages, and The London Atlas methods on panoramic radiograms of a total of 500 Turkish individuals aged 14-22 years. A logistic model was derived with an individual's adult or minor status as the dependent variable, and each method and sex as predictive variables. The adult status was determined using dental age estimation methods and the performance of these methods in differentiating adults from minors was evaluated. The three methods were compared case-wise for their accuracy in predicting adult status.

RESULTS

Logistic regression analysis showed that sex and each estimation method were statistically significant in discriminating adults and minors (p < 0.05). In the case-wise comparison for estimate adulthood, both Demirjian's stages and I_3M methods tended to perform better than the London Atlas method, with this trend reaching statistical significance (p < 0.05).

CONCLUSIONS

Cameriere's I_3M and Demirjian's development stages are useful methods for adult age assessment in the tested population.

CLINICAL RELEVANCE

In forensic medicine and legal practices, Cameriere's I_3M and Demirjian's maturation stage methods based on the development of the third molar teeth can be used to determine whether an individual is a minor or an adult.

Relationship Between the Eruption of Third Molar Teeth and the Growing Status of the Assamese Inhabitants of a North-Eastern State of India

Objectives

Even though permanent teeth eruption time may vary, the tooth eruption stage represents a critical developmental milestone, which may help in the monitoring of the child's growing status towards adolescence. This paper aims to evaluate the relationship between the third molar eruption (TME) and investigate any possible association with the body mass index (BMI), which is used to monitor the growth of children and adolescents.

Methods

We included 1060 student participants aged 14 to 26 years from selected educational institutions in Assam for this study. We performed a conventional clinical dental examination to determine the stages of TME. Moreover, to calculate the individual height and weight, we have carried out a thorough physical examination to assess the BMI and rule out any visible congenital developmental anomalies.

Result

The overall mean age of the status of no eruption (NE), incomplete eruption (IE), and complete eruption (CE) categories of the third molar in the current research were 17.39±2.273, 18.67±2.282 and 20.33±2.566 years, respectively, and the difference in mean age was statistically significant (p-value <0.05). Among the 1060 participants assessed, 163 (15.38%) were underweight, 625 (58.97%) belonged to the average category, 207 (19.52%) were at risk of being overweight, and 65 (6.13%) were obese. The CE in both average and overweight categories was 109 (17.4%) and 37 (17.9%). Similarly, the NE status of the third molar in the underweight and obese category was 120 (73.6%) and 39 (60.0%), respectively. These differences in the frequency of TME in different BMI categories were found statistically significant (p-value <0.05).

Conclusion

The result shows a substantial relationship between the mean age of eruption of third molar teeth and BMI among children and adolescents in 14 years to 26 years in the Assamese population. Further, the mean age can be used in forensic age determination.

Study of the ethnicity's influence on the third molar maturity index (I3M) for estimating age of majority in living juveniles and young adults

Estimation of age of majority has important applications in the forensic daily practice because of the increasing demand for age estimates of unaccompanied minors. Diagnostic accuracy of I_3M to assess legal adult age of 18 years has been already tested in several specific population samples. The aim of this work was to compare the available data about sensitivity and specificity of the third molar maturity index (I_3M) from five different regional groups' radiographic samples to study possible ethnical difference. For this purpose, a sample of 6157 orthopantomograms (OPGs), coming from 15 countries, was analysed. Data about sensitivity and specificity were pooled using a bivariate modelling approach. The one-way MANOVA analysis was applied to assess the likelihood that sensitivity and specificity of the five regional groups are sampled from the same population. The result of the one-way MANOVA showed that both sensitivity and specificity did not depend from the regional groups. The obtained sensitivity was 84% (95% CI: 82% and 85%), and its specificity was 94% (95% CI: 93% and 95%). Based on these results, the I_3M was a useful statistical tool to identify whether a subject has reached the legal age of 18 years old, regardless of his or her ethnicity.

Age estimation based on 3D post-mortem computed tomography images of mandible and femur using convolutional neural networks

Age assessment has attracted increasing attention in the field of forensics. However, most existing works are laborious and requires domain-specific knowledge. Modern computing power makes it is possible to leverage massive amounts of data to produce more reliable results. Therefore, it is logical to use automated age estimation approaches to handle large datasets. In this study, a fully automated age prediction approach was proposed by assessing 3D mandible and femur scans using deep learning. A total of 814 post-mortem computed tomography scans from 619 men and 195 women, within the age range of 20-70, were collected from the National Forensic Service in South Korea. Multiple preprocessing steps were applied for each scan to normalize the image and perform intensity correction to create 3D voxels that represent these parts accurately. The accuracy of the proposed method was evaluated by 10-fold cross-validation. The initial cross-validation results illustrated the potential of the proposed method as it achieved a mean absolute error of 5.15 years with a concordance correlation coefficient of 0.80. The proposed approach is likely to be faster and potentially more reliable, which could be used for age assessment in the future.

Evaluation of the Ossification Stage of Proximal Humeral Epiphysis by 1.5-T Magnetic Resonance Imaging for Determination of Skeletal Age

PURPOSE

The aim of the study was to investigate whether the skeletal age can be evaluated assessed by means of analysis of ossification stage at proximal humeral epiphysis using magnetic resonance imaging (MRI).

METHODS

This retrospective study was carried out in the radiology department of a tertiary healthcare center and 1.5-T MRI views of the shoulder obtained from 203 patients aged 8 to 29 years were evaluated. The ossification stage of proximal humeral epiphysis was evaluated on T1-weighted MRI sequences, and its correlation with age was sought.

RESULTS

Our series consisted of 77 women (37.9%) and 126 men (62.1%). One hundred forty-seven right humerus (72.4%) and 56 (27.6%) left humerus were examined. The mean age of the patients was 20.60 ± 4.41 years. The patients were in stages 4 (n = 148, 72.9%), 3c (n = 18, 8.9%), 3b (n = 14, 6.9%), 2c (n = 13, 6.4%), and 3a (n = 10, 4.9%). Analysis of the relationship between age and ossification stage of proximal humerus epiphysis indicated that stage increased with the advancement of age. There was a significant correlation between the stage and age variables at a rate of 77% in the positive direction (P < 0.001).

CONCLUSIONS

Our results demonstrated that MRI of proximal humeral epiphysis can have valuable implications for estimation of the skeletal age. Future prospective studies must be implemented with patients grouped according to socioeconomic status, nutritional habits, and physical activities to explore the actual investigative potential of MRI.

Forensic age estimation via magnetic resonance imaging of knee in the Turkish population: use of T1-TSE sequence

The evaluation of epiphyseal areas by magnetic resonance imaging (MRI) for forensic age estimation is an important supportive diagnostic method to prevent repeated radiation exposure without a valid medical reason. There are still not enough individuals being analyzed with MRI for age estimation. The aim of this study was to investigate the utility of T1-weighted turbo spin echo (T1-TSE) MRI sequences in determining the degree of ossification of the distal femoral and proximal tibial epiphyses in a Turkish population. In this study, images from 649 patients (335 males and 314 females) aged 10–30 years were retrospectively evaluated with sagittal T1-weighted turbo spin echo (T1-TSE) MRI sequences of the knee. Proximal tibial and distal femoral epiphysis were scored by two different observers twice using the combined staging system described by Schmeling and Kellinghaus. Spearman’s rank correlation analysis indicated a significant positive relationship between age and ossification stages of the distal femoral and proximal tibial epiphyses (p < 0.001). The intra- and inter-observer reliabilities in evaluating the femur and tibia were separately determined and gave promising results and Cohen’s kappa statistics ranged from κ = 0.886 and κ = 0.961. The minimal ages of patients with stage 4 ossification were 15.1 years for females and 15.8 years for males for the distal tibial epiphysis and 15.4 years for females and 17 years for males for the distal femoral epiphysis. This study show that (T1-TSE) MRI and the applicability and Schmeling and Kellinghaus staging method of the knee can be performed for living 14- to 17-year-old individuals in need of a supportive noninvasive method for estimating forensic age.

Analysis of carpal bones on MR images for age estimation: First results of a new forensic approach

Current multifactorial age estimation methods are based on radiography, however, in the forensic field there is growing interest in using magnetic resonance imaging (MRI). With regard to the carpal region, MRI provides more information for defining the individual ossification nuclei and the cartilage surrounding single bones. During the phase of bone growth, the progressive reduction of the cartilage layer is accompanied by the development of a cartilage-bone interface. The aim of our study was to create a new model for age estimation, based on the ratio between the area occupied by the nucleus of ossification (NO) and the surface of growth (SG) of each carpal bone, the latter derived by adding NO to the area of cartilage-bone interface. We analyzed 57 MRI scans of Italian subjects aged between 12 and 20 years, without growth diseases, endocrine disorders or osteodystrophy. Measurements of NO and SG areas were extracted using ImageJ software, and the ratio between the NO and SG of each bone (NOSG) was calculated. A multiple linear regression model was used to estimate the individual's age as a function of the variables: gender and wrist bone measurements. The results showed that the best model was obtained with 6 predictors (nvmax=6): Gender, and the NOSG of the Trapezoid, Trapezium, Scaphoid, Pisiform, and Capitate. The median of the residuals (observed age minus predicted age) was -0.025 years, with an IQR of 0.19 years. Thus a new forensic approach to age assessment using MRI is introduced in this paper, which gives the preliminary results.

Validation of the third molar maturity index cut-off value of <0.08 for indicating legal age of 18 years in Eastern Chinese region

Having a reliable, inexpensive and simple method to estimate 18 years of age would be of help in the forensic field. This study aimed to test the accuracy of the third molar maturity index (I_3M) in indicating the legal adult age of 18 years. This retrospective cross-sectional study analysed 450 digital panoramic images of Eastern Chinese children and young adults (226 females and 224 males) aged between 14 and 22 years. A cut-off value of I_3M < 0.08 was tested in discriminating adults from minors for both sex. For females, the sensitivity of the test (Se) was 75.0%, with a 95% confidence interval (95%CI) of 67.5% to 82.5%. The specificity of the test (Sp) was 100%. The proportion accurately classified (Ac) individuals was 85.8% (95%CI, 81.3% to 90.4%). The Bayes post-test probability was 100% (93.6% to 100%). For males, Se, Sp and Ac were 91.9% (95%CI, 87.1% to 96.7%), 92.0%(95%CI, 86.7% to 97.3%) and 92% (95%CI, 88.4% to 95.5%), respectively. The Bayes post-test probabilities was 92% (95%CI, 88.4% to 95.5%). Males were ahead in the development of third molars comparing to females according to I_3M. A stepwise logistic regression analysis showed that both I_3M and sex contribute to the regression model to discriminate adults (≥18 years) from minors (<18 years), while a receiver operating curve (ROC) analysis indicated some better accuracy of I_3M < 0.12 in females, without statistically significant difference when compared to I_3M < 0.08. The results of this study show that the cut-off value of I_3M < 0.08 may help to discriminate Eastern Chinese adults from minors. However, further study should evaluate the usefulness and possible variability of I_3M cut-off value in a specific population before used for legal and forensic procedures.

Cameriere's third molar maturity index in assessing age of majority: a study of a French sample

Forensic age estimation is a challenging field in forensic sciences because of the increase of migratory flows. Medicolegal age assessment is a key point because it has many implications for authorities. Dental age estimation is an essential part of the global age assessment. The aim of this study was to evaluate and test the accuracy of Cameriere's cutoff values of the third molar maturity index (I3M) in assessing legal adult age of 18 years in a French population. The sample was constituted of 431 orthopantomograms performed between January 2014 and August 2017 on patients aged between 14 and 22 years. The reproducibility and repeatability of the method were high. Age distribution gradually decreases as I3M increases in both sexes. 0.08 seemed to be the best I3M cutoff. For females, the sensitivity and specificity of the test were 74.51% and 88.23%, respectively. The sensitivity and specificity for males were 92.19% and 88.35%, respectively. The accuracies were 80.74% for female, 90.57% for male. Estimated post-test probabilities were 0.879 for female and 0.899 for male. To conclude, the specific cutoff value of I3M ˂ 0.08 may be a useful additional tool in discriminating adults and minors in French population.

Automated age estimation from MRI volumes of the hand

Highly relevant for both clinical and legal medicine applications, the established radiological methods for estimating unknown age in children and adolescents are based on visual examination of bone ossification in X-ray images of the hand. Our group has initiated the development of fully automatic age estimation methods from 3D MRI scans of the hand, in order to simultaneously overcome the problems of the radiological methods including (1) exposure to ionizing radiation, (2) necessity to define new, MRI specific staging systems, and (3) subjective influence of the examiner. The present work provides a theoretical background for understanding the nonlinear regression problem of biological age estimation and chronological age approximation. Based on this theoretical background, we comprehensively evaluate machine learning methods (random forests, deep convolutional neural networks) with different simplifications of the image information used as an input for learning. Trained on a large dataset of 328 MR images, we compare the performance of the different input strategies and demonstrate unprecedented results. For estimating biological age, we obtain a mean absolute error of 0.37 ± 0.51 years for the age range of the subjects  ≤  18 years, i.e. where bone ossification has not yet saturated. Finally, we validate our findings by adapting our best performing method to 2D images and applying it to a publicly available dataset of X-ray images, showing that we are in line with the state-of-the-art automatic methods for this task.

Forensic age estimation of 85 male child laborers and 31 rescued female commercial sex workers from Hyderabad in South India

Age estimation in living individuals has attained importance in forensic sciences from legal proceedings and has been a frequent request from concerned authorities to ascertain whether the person in question has reached the age of imputability and legal responsibility. The purpose of age estimation is not just limited to juvenile or sub-adult delinquents but also required in situations like a violation of child rights such as child employment, commercial sexual exploitation involving minor girls. Indian Law strictly forbids any employment of the children under the age of 14 and sexual exploitation of minor girls (<18 years). In this study, we assessed the skeletal and dental ages and correlate to reported chronological ages in a sample of 85 male child labourers and 31 female commercial sex workers. Statistical analysis of the results was performed to verify the similarities or differences between reported and biological age. The results had revealed a statistically significant difference between the reported age, skeletal, dental, and calculated biologic age (p < 0.05). The results indicate the need to establish a more reliable method for determining the biological age in an age-specific population.

Forensic age estimation based on the pigmentation in the costal cartilage from human mortal remains

Age estimation is considered a crucial and challenging issue in forensic casework. Costal cartilage appears a potential mortal remain in age-at-death estimation attributable to its correlative alteration in color based on pigment accumulation with the advancing age. In this study, samples from the second costal cartilage were collected in a Chinese Han population, and the cross sections were subsequently scanned and digitalized in a standard way. Color change was quantified using mean gray value (MGV), which was measured by Photoshop CS5. After the exclusion of samples with factors which could impair the quality of images and the accuracy of values, a high correlation was demonstrated between age and MGV in samples. A linear regression model (AGE = 173.425-0.755*aveMGV) was established for age prediction, with its performance evaluated using both samples from the training set and the blind test set, in which a mean absolute deviation of 4.42 years and 3.57 years was obtained, respectively. Altogether, MGV could be reckoned as a precise quantification of pigmentation in costal cartilage and an excellent indicator of age prediction in the age interval from 20 to 60 years. Moreover, our strategy appears more user-friendly and accurate, thus exceedingly practical for age estimation in forensic anthropology.

Forensic age diagnostics by magnetic resonance imaging of the proximal humeral epiphysis

The most commonly used radiological method for age estimation of living individuals is X-ray. Computed tomography is not commonly used due to high radiation exposure, which raises ethical concerns. This problem can be solved with the use of magnetic resonance imaging (MRI), which avoids the use of ionizing radiation. The purpose of the present study was to evaluate the utility of MRI analysis of the proximal humeral epiphyses for forensic age estimations of living individuals. In this study, 395 left proximal humeral epiphyses (patient age 12-30 years) were evaluated with fast-spin-echo proton density-weighted image (FSE PD) sequences in a coronal oblique orientation on shoulder MRI images. A five-stage scoring system was used following the method of Dedouit et al. The intra- and interobserver reliabilities assessed using Cohen's kappa statistic were κ = 0.818 and κ = 0.798, respectively. According to this study, stage five first appeared at 20 and 21 years of age in males and females, respectively. These results are not directly comparable to any other published study due to the lack of MRI data on proximal humeral head development. These findings may provide valuable information for legally important age thresholds using shoulder MRI. The current study demonstrates that MRI of the proximal humerus can support forensic age estimation. Further research is needed to establish a standardized protocol that can be applied worldwide.

Union of the medial clavicular epiphysis in a South African Black skeletal sample

Current research points to an increase in the interest in and focus on the age at which the medial end of the clavicle begins and completes union in various populations worldwide. As it currently stands, no information exists for the South African population detailing the age at which this skeletal developmental marker commences or completes union. The aim of this study was to establish the age at which partial and complete unions occur and to find if there is any correlation between the age and the assigned stage score in a South African Black skeletal sample. Paired clavicles of 211 males and females (M = 101, F = 110) with ages ranging between 12 and 45 years from the Raymond A. Dart Collection of Human Skeletons were included. A strong correlation between age and the assigned stage score was observed for both males and females (rs = 0.73). No statistically significant differences between the stage of union at the left and right clavicles were observed (p = 0.9). In this sample, partial union was commonly observed in individuals in their third decade of life; while complete union occurred more often in individuals older than 30 years of age. Assessing and recording the degree of union at the medial end of the clavicle can be a helpful additional age-at-death indicator to use when establishing an age-at-death range. However, overlap and variability between the ages of individuals categorized as either displaying signs of partial or complete union were evident.

Estimating age using permanent molars and third cervical vertebrae shape with a novel semi-automated method

Estimating chronological age accurately in young adults is difficult and additional methods are required to increase the accuracy. This study explored a new semi-automated method to assess shape change of third cervical vertebra (C3) with age in the living; comparing this as a method to determine whether individuals could be categorised into being less than 18 years of age (<18), or at least 18 years of age (≥18) with tooth formation of the second and third mandibular molars (M2 and M3). The sample was panoramic and lateral skull radiographs of 174 dental patients (78 males, 96 females aged 15-22 years). Twelve variables were compared in two age categories: younger than 18 and at least 18 years of age in males and females separately using a t-test. Tooth formation of M2 and M3 was assessed. Mean values of eight variables of C3 in males and one variable in females were significantly different between the two age categories (p < 0.05). Results for males showed that the best age indicator for age ≥18 was the ratio between height and width of C3 and for females, the ratio between diagonals. Results for molars showed that M2 was mature in 69% of males and 83% of females, within the expected age range of 14-16 years. M3 was highly variable ranging from stages 6-14 for both; M3 was missing in 24% of males and 28% of females and mature in 14% of males and 15% of females. The conclusion was that shape change of C3 has potential as an additional method to group individuals <18 and ≥ 18 years of age.

Applicability of T1-weighted MRI in the assessment of forensic age based on the epiphyseal closure of the humeral head

This work investigates the value of magnetic resonance imaging analysis of proximal epiphyseal fusion in research examining the growth and development of the humerus and its potential utility in establishing forensic age estimation. In this study, 428 proximal humeral epiphyses (patient age, 12-30 years) were evaluated with T1-weighted turbo spin echo (T1 TSE) sequences in coronal oblique orientation on shoulder MRI images. A scoring system was created following a combination of the Schmeling and Kellinghaus methods. Spearman's rank correlation analysis revealed a significant positive relationship between age and ossification stage of the proximal humeral epiphysis (all subjects: rho = 0.664, p < 0.001; males: 0.631, p < 0.001; females: rho = 0.651, p < 0.001). The intra- and inter-observer reliability assessed using Cohen's kappa statistic was κ = 0.898 and κ = 0.828, respectively. The earliest age of epiphysis closure was 17 years for females and 18 years for males. MRI of the proximal humeral epiphysis can be considered advantageous for forensic age estimation of living individuals in a variety of situations, ranging from monitoring public health to estimating the age of illegal immigrants/asylum seekers, minors engaged in criminal activities, and illegal participants in competitive sports, without the danger of radiation exposure.

When forensic odontology met biochemistry: Multidisciplinary approach in forensic human identification

When human remains are found, the priority of the investigation is to ascertain the identity of the deceased. A positive identification is a key factor in providing closure for the family of the deceased; it is also required to issue the death certificate and therefore, to settle legal affairs. Moreover, it is difficult for any forensic investigation involving human remains to be solved without the determination of an identity. Therefore, personal identification is necessary for social, legal and forensic reasons. In the last thirty years forensic odontology has experienced an important transformation, from primarily involving occasional dental identification into a broader role, contributing to the determination of the biological profile. In the same way, "DNA fingerprinting" has evolved not only in terms of improving its technology, but also in its application beyond the "classical": helping with the estimation of sex, age and ancestry. As these two forensic disciplines have developed independently, their pathways have crossed several times through human identification operations, especially the ones that require a multidisciplinary approach. Thus, the aim of this review is to describe the contributions of both forensic odontology and molecular biology/biochemistry to human identification, demonstrating how a multidisciplinary approach can lead to a better and more efficient identification.

Ethical aspects of medical age assessment in the asylum process: a Swedish perspective

According to European regulations and the legislations of individual member states, children who seek asylum have a different set of rights than adults in a similar position. To protect these rights and ensure rule of law, migration authorities are commonly required to assess the age of asylum seekers who lack reliable documentation, including through various medical methods. However, many healthcare professionals and other commentators consider medical age assessment to be ethically problematic. This paper presents a simplified and amended account of the main findings of a recent ethical analysis of medical age assessment in the asylum process commissioned by the Swedish National Board of Health and Welfare. A number of ethical challenges related to conflicting goals, equality and fairness, autonomy and informed consent, privacy and integrity, and professional values and roles are identified and analysed. It is concluded that most of these challenges can be met, but that this requires a system where the assessment is sufficiently accurate and where adequate safeguards are in place. Two important ethical questions are found to warrant further analysis. The first is whether asylum seekers' consent to the procedure can be considered genuinely voluntary. The second is whether and how medical age assessments could affect negative public attitudes towards asylum seekers or discriminatory societal views more generally.

A new approach for the analysis of facial growth and age estimation: Iris ratio

The study of facial growth is explored in many fields of science, including anatomy, genetics, and forensics. In the field of forensics, it acts as a valuable tool for combating child pornography. The present research proposes a new method, based on relative measurements and fixed references of the human face—specifically considering measurements of the diameter of the iris (iris ratio)—for the analysis of facial growth in association with age in children and sub-adults. The experimental sample consisted of digital photographs of 1000 Brazilian subjects, aged between 6 and 22 years, distributed equally by sex and divided into five specific age groups (6, 10, 14, 18, and 22 year olds ± one month). The software package SAFF-2D^® (Forensic Facial Analysis System, Brazilian Federal Police, Brazil) was used for positioning 11 landmarks on the images. Ten measurements were calculated and used as fixed references to evaluate the growth of the other measurements for each age group, as well the accumulated growth (6–22 years old). The Intraclass Correlation Coefficient (ICC) was applied for the evaluation of intra-examiner and inter-examiner reliability within a specific set of images. Pearson’s Correlation Coefficient was used to assess the association between each measurement taken and the respective age groups. ANOVA and Post-hoc Tukey tests were used to search for statistical differences between the age groups. The outcomes indicated that facial structures grow with different timing in children and adolescents. Moreover, the growth allometry expressed in this study may be used to understand what structures have more or less proportional variation in function for the age ranges studied. The diameter of the iris was found to be the most stable measurement compared to the others and represented the best cephalometric measurement as a fixed reference for facial growth ratios (or indices). The method described shows promising potential for forensic applications, especially as part of the armamentarium against crimes involving child pornography and child abuse.

The Effects of the Refugee Crisis on Age Estimation Analysis over the Past 10 Years: A 16-Country Survey

Dental age estimation (AE) tests are routinely done on living and deceased persons. There is anecdotal evidence suggesting an increase in age estimations due to the refugee crisis. Our aim is to determine the reasons and methods for performing dental AE tests in both living and deceased individuals. Global trends in AE over the past 10 years were also investigated. A database of all forensic laboratories was obtained and an electronic questionnaire was sent to all of them. The questionnaire was self-developed and included questions on the reasons for performing AE tests, the preferred methods used in living and deceased individuals, and the people/organizations who requested these AE tests. The number of tests performed annually varied between 0 and 500 and the majority were on asylum seekers, refugees, and for adoption cases. Most units used multiple techniques to determine the age among the living, but seldom used more than three techniques for the deceased. The majority of tests were requested by coroners and the legal fraternity. There has been an increase in the number of dental AEs carried out and this has been mostly due to asylum seekers and refugees. The most common techniques for the living were variations of Demirjian’s technique while country specific techniques were used for the deceased.

Forensic age estimation by morphometric analysis of the manubrium from 3D MR images

Forensic age estimation research based on skeletal structures focuses on patterns of growth and development using different bones. In this work, our aim was to study growth-related evolution of the manubrium in living adolescents and young adults using magnetic resonance imaging (MRI), which is an image acquisition modality that does not involve ionizing radiation. In a first step, individual manubrium and subject features were correlated with age, which confirmed a statistically significant change of manubrium volume (M_vol:p<0.01, R²¯=0.50) and surface area (M_sur:p<0.01, R²¯=0.53) for the studied age range. Additionally, shapes of the manubria were for the first time investigated using principal component analysis. The decomposition of the data in principal components allowed to analyse the contribution of each component to total shape variation. With 13 principal components, ∼96% of shape variation could be described (M_shp:p<0.01, R²¯=0.60). Multiple linear regression analysis modelled the relationship between the statistically best correlated variables and age. Models including manubrium shape, volume or surface area divided by the height of the subject (Y∼M_shpM_sur/S_h:p<0.01, R²¯=0.71; Y∼M_shpM_vol/S_h:p<0.01, R²¯=0.72) presented a standard error of estimate of two years. In order to estimate the accuracy of these two manubrium-based age estimation models, cross validation experiments predicting age on held-out test sets were performed. Median absolute difference of predicted and known chronological age was 1.18 years for the best performing model (Y∼M_shpM_sur/S_h:p<0.01, R_p²=0.67). In conclusion, despite limitations in determining legal majority age, manubrium morphometry analysis presented statistically significant results for skeletal age estimation, which indicates that this bone structure may be considered as a new candidate in multi-factorial MRI-based age estimation.

Forensic age estimation of living persons from the knee: Comparison of MRI with radiographs

To perform a study to clarify how strong the chronological age relates to ossification of the knee in Chinese on X-rays and the MRI when a similar four-stage grading system was used. 322 individuals with conventional radiographs and MRI were collected from routine medical investigations and evaluated retrospectively. Bland Altman plots were performed to reveal the agreement of grading of MRI and radiograph. Regression analysis was conducted to establish a mathematical model for age estimation. The ossification process of the knee occurs earlier in females than in males for about 1-2 years. The process on X-ray grading is consistently higher than that of MRI. The chronological age is well correlated with both grading of MRI and radiograph (all p values were less than 0.001). By comparison, the R-square of grading of MRI were relatively higher than that of radiograph. Finally, the chronological age is well correlated with the ossification of the knee when both grading of MRI and radiograph were used, with the R-square for MRI were relatively higher than that of radiograph. Furthermore, the use of MRI will reduce exposure to X-ray radiation as much as possible.

Dentistry to the rescue of missing children: A review

Today's society is becoming increasingly unsafe for children: we frequently hear about new incidents of missing children, which lead to emotional trauma for the loved ones and expose systemic failures of law and order. Parents can take extra precautions to ensure the safety of their children by educating them about ways to protect themselves and keep important records of the child such as updated color photographs, fingerprints, deoxyribonucleic acid (DNA) samples, etc., handy. However, in spite of all efforts, the problem of missing children still remains. Developments in the field of dentistry have empowered dentists with various tools and techniques to play a pivotal role in tracing a missing child. One such tool is Toothprints, a patented arch-shaped thermoplastic dental impression wafer developed by Dr. David Tesini, a paediatric dentist from Massachusetts. Toothprints enables a unique identification of the missing children not only through the bite impression but also through salivary DNA. Besides the use of Toothprints, a dentist can assist investigating agencies in identifying the missing children in multiple ways, including postmortem dental profiling, labeled dental fixtures, DNA extraction from teeth, and serial number engraving on the children's teeth. More importantly, all these tools cause minimal inconvenience to the individual, making a dentist's role in tracking a missing child even more significant. Thus, the simple discipline of maintaining timely dental records with the help of their dentists can save potential hassles for the parents in the future.

Skeletal age estimation in a contemporary Western Australian population using the Tanner-Whitehouse method

Various age estimation techniques have been utilised in Australia to evaluate the age of individuals who do not have documentation to determine legal majority/culpability. These age estimation techniques rely on the assessment of skeletal development as visualised in radiographs, CT scans, MRI or ultrasound modalities, and subsequent comparison to reference standards. These standards are not always population specific and are thus known to be less accurate when applied outside of the original reference sample, leading to potential ethical implications. Therefore, the present study aims to: (i) explore the variation in developmental trajectories between the established Tanner-Whitehouse (TW) age estimation standards and a Western Australian population; and (ii) develop specific hand-wrist age estimation standards for the latter population. The present study examines digital anterior-posterior hand-wrist radiographs of 360 individuals 0 to 24.9 years of age, equally represented by sex. Each radiograph was assessed using the RUS, Carpal and 20-bone methods of Tanner et al. The standard error of the estimate (SEE) was calculated for each method (range: ♀ SEE ±0.4-11.5 years; ♂ SEE ±0.9-10.1 years). The most accurate method was TW3 RUS for females and the TW2 Carpal system for males. The 50th centile skeletal maturity scores for each year age group were plotted against average chronological age to produce polynomial regression standards with a demonstrated accuracy of (♀ SEE ±0.09-3.46 years; ♂ SEE ±0.02-3.42 years) for females and males, respectively. The standards presented here can be used in future forensic investigations that require age estimation of hand-wrist bones in a Western Australian population, however, they are not appropriate for establishing age of majority (18 years), as skeletal maturity was attained on average earlier than 15 years of age in both sexes for all three systems examined.

Third molar maturity index (I3M) for assessing age of majority in a black African population in Botswana

Assessment of legal age, also known as age of majority, is a controversial issue as there are few body biomarkers or evidence during late adolescence differentiating a subject from being a minor or adult. The third molar was recognized as a suitable site for age examination in late adolescence. We analyzed the development of the left mandibular third molar by the third molar maturity index (I3M) and a specific cut-off value of I3M = 0.08, established by Cameriere et al. in 2008 and used it for discriminating between minors and adult black Africans from Gaborone, Botswana. A final sample of panoramic radiographs (OPTs) of 1294 people (582 males and 712 females) aged between 13 and 23 years was evaluated. The real age decreased as I3M gradually increased. There was no statistically significant difference in the third molar development evaluated using I3M between males and females (p > 0.05) across different I3M classes. Results of 2 × 2 contingency tables for different cut-off values indicated that I3M = 0.08 was useful in discriminating between adults and minors. Precisely, for I3M = 0.08, the values of accuracy or overall fraction of correctly classified were 0.91 in males with a 95 % confidence interval (95 % CI) of 0.88 to 0.93 and 0.92 (95 % CI, 0.90 to 0.93) in females. Values of sensitivity of the test or the proportion of participants being 18 years and older were 0.88 (95 % CI, 0.87 to 0.90) in males and 0.88 (95 % CI, 0.90 to 0.93) in females, while values of specificity or proportion of individuals younger than 18 who have I3M <0.08 were 0.94 (95 % CI, 0.91 to 0.96) in males and 0.96 (95 % CI, 0.94 to 0.98) in females. Positive predictive values of the test, where the participants whose I3M <0.08 were adults, were 0.94 (95 % CI 0.91 to 0.96) in males and 0.97 (95 % CI, 0.94 to 0.98) in females, while negative predictive values of the test, where the participants whose I3M was ≥0.08 were minors, were 0.88 (95 % CI 0.85 to 0.90) in males and 0.97 (95 % CI, 0.94 to 0.98) in females. The likelihood ratios of the positive test (LR+) were 13.67 (95 % CI, 9.21 to 21.02) in males and 23.73 (95 % CI, 14.20 to 42.28) in females, while likelihood ratios of the negative test (LR-) were 0.12 (95 % CI 0.10 to 0.16) in males and 0.12 (95 % CI, 0.11 to 0.15) in females. Bayes post-test probabilities, p, were 0.94 (95 % CI 0.90 to 0.98) in males and 0.97 (95 %CI, 0.93 to 1.00) in females. These results indicate with high accuracy that I3M may be a useful alternative method in legal and forensic practice to discriminate individuals of black African origin who are around the legal adult age of 18 years in Botswana. Further studies should address the usefulness of this method and specific cut-off for different adolescent populations.

Third molar development by measurements of open apices in an Italian sample of living subjects

The aim of this study is to analyse the age-predicting performance of third molar index (I3M) in dental age estimation. A multiple regression analysis was developed with chronological age as the independent variable. In order to investigate the relationship between the I3M and chronological age, the standard deviation and relative error were examined. Digitalized orthopantomographs (OPTs) of 975 Italian healthy subjects (531 female and 444 male), aged between 9 and 22 years, were studied. Third molar development was determined according to Cameriere et al. (2008). Analysis of covariance (ANCOVA) was applied to study the interaction between I3M and the gender. The difference between age and third molar index (I3M) was tested with Pearson's correlation coefficient. The I3M, the age and the gender of the subjects were used as predictive variable for age estimation. The small F-value for the gender (F = 0.042, p = 0.837) reveals that this factor does not affect the growth of the third molar. Adjusted R(2) (AdjR(2)) was used as parameter to define the best fitting function. All the regression models (linear, exponential, and polynomial) showed a similar AdjR(2). The polynomial (2nd order) fitting explains about the 78% of the total variance and do not add any relevant clinical information to the age estimation process from the third molar. The standard deviation and relative error increase with the age. The I3M has its minimum in the younger group of studied individuals and its maximum in the oldest ones, indicating that its precision and reliability decrease with the age.

Dental age assessment of Western Saudi children and adolescents

Aim

The aim of this study was to evaluate the use of the London Atlas of Human Tooth Development and Eruption for age estimation in Saudi Arabian children and adolescents (aged 2–20 years), for forensic odontology application.

Materials and methods

This cross-sectional survey analyzed orthopantomograms (OPGs) of the complete dentition (including root development) to estimate the deviation from chronological age. Each OPG was de-identified and analyzed individually and classified into age-groups by the lead author, using the methods of the Atlas of Tooth Development.

Results

OPGs from a total of 252 patients [110 (44%) males, 142 (56%) females] aged 2–20 years (24–240 months) were examined in this study. The average estimated and chronological ages of subjects differed significantly p < 0.001 (143 ± 55.4 vs. 145 ± 57.9 months). Most (65.5%) estimates were within 12 months of subjects’ chronological ages; 19% overestimated and 15.5% underestimated age by >12 months.

Conclusion

This study, conducted in a sub-population of different origin than the UK sample used for the development of the London Atlas, identified variation in age estimates that may have significant impacts on results. The establishment of a composite international repository of atlas-based data for diverse ethnic sub-populations would be of great value to clinicians across the globe.

Estimation of legal age using calcification stages of third molars in living individuals

The increased number of adolescents and young adults with unknown or inaccurately given date of birth is a current issue in justice and legal medicine. The objective of this study was to determine the extent to which third molar calcification stages assessed on panoramic X-rays could be useful as additional criteria for forensic age estimation in living individuals, focusing on the legally important ages 17 and 18. In a retrospective multi-center study, the developmental stage of each individual's third molar was analyzed using Demirjian's scale in 2360 cases. Additionally, sex, age and ancestry were assessed. Individuals with the lowest calcification stage of all present molars in stage H were ≥18 years with a likelihood of ≥99.05% in the female (n=388), and ≥99.24% in the male (n=482) population. The lowest calcification stage of all present third molars proved to be useful as an additional reliable criterion for the determination of an age ≥18 years.

Estimation of age from development and eruption of teeth

The developing dentition is used to assess maturity and estimate the age in many disciplines including anthropology, archeology, forensic science, pediatric dentistry and orthodontics. There is evidence that dental development is less effected than skeletal development by malnutrition and hormonal disorders. There are two methods of dental age assessment, radiographically and by clinically visualization of eruption of teeth. The clinical method to assess dental age is based on the emergence of teeth in the mouth. This method is more suitable since it does not require any special equipment, expertise and is more economical. Tooth formation is the best choice for estimating the age as variations are less as compared to other development factors. Eruption of teeth is one of the changes observed easily among the various dynamic changes that occur from the formation of teeth to the final shedding of teeth. The times of eruption of teeth are fairly constant and this can be made use of in ascertaining the average age of eruption of the tooth. Assessment of age of an individual by examination of teeth is one of the accepted methods of age determination.

Estimation of age from development and eruption of teeth

The developing dentition is used to assess maturity and estimate the age in many disciplines including anthropology, archeology, forensic science, pediatric dentistry and orthodontics. There is evidence that dental development is less effected than skeletal development by malnutrition and hormonal disorders. There are two methods of dental age assessment, radiographically and by clinically visualization of eruption of teeth. The clinical method to assess dental age is based on the emergence of teeth in the mouth. This method is more suitable since it does not require any special equipment, expertise and is more economical. Tooth formation is the best choice for estimating the age as variations are less as compared to other development factors. Eruption of teeth is one of the changes observed easily among the various dynamic changes that occur from the formation of teeth to the final shedding of teeth. The times of eruption of teeth are fairly constant and this can be made use of in ascertaining the average age of eruption of the tooth. Assessment of age of an individual by examination of teeth is one of the accepted methods of age determination.

Evaluation of an automatic method for forensic age estimation by magnetic resonance imaging of the distal tibial epiphysis--a preliminary study focusing on the 18-year threshold

The contribution of magnetic resonance imaging to forensic age estimation of living individuals is a subject of ongoing research. Several studies have focused on the wrist, clavicle, knee, and foot, and shown interesting results regarding the 18-year threshold. Authors have developed various staging systems for epiphyseal growth plate maturation. However, the procedure is observer-dependent and requires experience and a certain time-learning process. To reduce these pitfalls, we have developed an automatic method based on the analysis of variations of gray levels within the epiphyseal-metaphyseal junction. This method was tested on 160 MRI scans of the distal tibial epiphysis in a sample of individuals aged from 8 to 25 years old, after intensity non-uniformity correction of all images. Results showed that in our sample, 97.4 % of males and 93.9 % of females aged 18 years or more would be correctly classified using this method. To our knowledge, automatic methods for MRI analysis have not been used in the field of age estimation yet. Further studies should be performed to assess the validity of this procedure.