The Biological Profile of Unidentified Human Remains in a Forensic Context

Exploring optimal methods for age-at-death estimation using pulp/tooth area ratios: a South African study

Age-at-death estimation is pivotal in the identification of unknown human decedents in forensic medicine. The pulp/tooth area ratio (PAR) method, assessing pulp cavity size as a marker of secondary dentine apposition, is widely utilised for adult age estimation. Despite extensive evaluation of this technique, the influence of image type and enamel area inclusion on method accuracy is insufficiently explored. The present study evaluated the PAR method's applicability using maxillary canines from a South African cadaveric sample, examining reliability, sex bias, and accuracy across different image types and enamel area considerations. An observational, cross-sectional study design was followed. Fifty-two adult maxillary canines were radiographed, sectioned, and analysed using stereomicroscopy. Labiolingual and mesiodistal periapical radiographs, alongside labiolingual stereomicroscopic tooth section images, were analysed using ImageJ to calculate PARs. Age estimation linear regression models were developed for each image type, with and without enamel area inclusion. Models were compared for performance and accuracy using best-subsets regression and cross-validation analyses. Results indicated that the PAR method is a reliable, sex-independent technique, providing relatively accurate age-at-death estimates for South African adults. Image type significantly influenced accuracy, with tooth section images exhibiting the best/lowest error values, followed by labiolingual and mesiodistal radiographs, respectively. Exclusion of enamel area consistently enhanced model performance across all image types. This study contributes valuable data to the underexplored field of dental age estimation techniques for South African adults, highlighting optimal approaches when applying the PAR method to maxillary canines. Additionally, it introduces a refined stereomicroscopic technique, augmenting and enhancing existing practices.

Dental age estimation in adults using the Lamendin criteria: Validation of a bayesian model in the Brazilian population

Age estimation provides information for biological profile, which is used as an important data during the process of to aid in the identification of bodies of deceased persons. Lamendin et al. proposed a simplified dental age estimation technique for adults based on the analysis of periodontal recession height, root height, and root translucency height. These characteristics were used to build a multi-population database that served in the development of a Bayesian model, known as the Forensic International Dental Database (FIDB). However, before this research, this model did not incorporate dental information from the Brazilian population. The aim of this article was to validate the application of the FIDB Bayesian statistical model for estimating dental age in samples from the Brazilian population and compare it to Lamendin's technique. A cross-sectional study was conducted using 230 dental elements extracted for therapeutic reasons and stored in a biobank. Two independent and calibrated examiners collected the data, considering the randomization of dental samples. Intra- and inter-examiner reliability analysis included the re-evaluation of 20 % (n = 40) of the sample. For statistical analyses, the data were organized in Microsoft© Excel© 365 version 2204 (Microsoft Corp., Redmond, WA, USA) spreadsheets, and R version 4.0.2 (R Foundation, Vienna, Austria) and IBM® SPSS® version 23.0 (SPSS Inc., IBM, Chicago, IL, USA) software were used. After applying inclusion and exclusion criteria, the final sample comprised 200 intact dental elements from 84 male and 116 female individuals. According to the Kolmogorov-Smirnov test, the data did not show a normal distribution, and the Intraclass Correlation Coefficient indicated that intra- and inter-examiner agreements were adequate. Through the Mann-Whitney U test, statistically significant differences between sexes were not observed. In terms of overall accuracy, the Bayesian model and the original Lamendin´s technique showed a mean absolute error of 9.39 years and 9.95, respectively. Regarding bias, it was generally 0.15 years for the Bayesian model and 5.62 years for the original Lamendin´s technique. The Wilcoxon classification test revealed no statistically significant difference between chronological and estimated ages, but only for the Bayesian model. It can be concluded that the developed Bayesian statistical model was able to estimate the age of Brazilian adults satisfactorily, and overall, the error rates were acceptable.

Fluctuating asymmetry in third molar agenesis as an aid to estimate socioeconomic status

Traditionally, dental identification techniques are used to establish identity or assist in reconstructing an individual's biological profile. However, other aspects of identity, namely socioeconomic status (SES), can be estimated through teeth. This work aims to evaluate the influence of SES on third molar agenesis in a Portuguese population. X-rays from 448 subjects (223 belonging to a high and 225 to a low socioeconomic status) were assessed and demographic data (age, sex) and dental history were registered. Frequencies and associations between the variables were analyzed using the chi-square test. For each group, differences between third molar agenesis were studied using the Wilcoxon test. The significance level was 5%. X-rays displaying at least one agenesis were more common in females (in both SES groups). Differences between socioeconomic status were found in female subjects' upper right and lower left third molars, with a higher frequency of agenesis in the lower SES group. Agenesis of lower third molars displayed fluctuant asymmetry in both groups, whereas agenesis of upper third molars was also present in the lower SES group. These results suggest that socioeconomic status can affect third molar agenesis prevalence, and fluctuant asymmetry seems more prevalent in the lower SES, as it affects all third molars.

Correlation of spheno-occipital synchondrosis and mandibular condylar cortication with chronological age using computed tomography in Indian population- A cross-sectional study

BACKGROUND

Forensic age estimation is a procedure which utilises many methods to estimate the age of both living and deceased individuals, including those who have died in natural disasters or man-made catastrophes. The pattern and closure of spheno-occipital synchondrosis (SOS) fusion, along with subchondral ossification of the mandibular condyle, can be used to estimate age.

AIM AND OBJECTIVES

This study aims to estimate age using computed tomographic (CT) images of spheno-occipital synchondrosis fusion (SOS) and mandibular condylar cortication (MCC), and to correlate these findings with chronological age.

MATERIALS AND METHODS

The present study included 435 CT images of individuals aged 10-25 years. SOS fusion was assessed using a four-stage system, and MCC was assessed bilaterally using a three-stage system on the sagittal plane. Data on fusion stages and cortication types were entered along with chronological age, and then statistically analysed.

RESULTS

SOS fusion stage 2 occurred at similar age in males (19.82 ± 2.67 years) and females (19.23 ± 2.93 years). Earlier fusion of other stages was observed in females by a mean age of 2 years. MCC was completed 1 year earlier in females, with statistically significant differences (p ≤ 0.001). When comparing cortication types and different fusion stages, only type II cortication showed statistically significant differences compared to different fusion stages (p ≤ 0.001).

CONCLUSION

Mandibular condylar cortication (MCC) and spheno-occipital synchondrosis (SOS) fusion were positively correlated with chronological age, suggesting that these parameters can be used as an adjunct method for age estimation.

Reliability of predictive models based on the mesiodistal and buccolingual diameters of permanent canine teeth for sex estimation in forensic contexts: A systematic review and meta-analysis

This study aimed to assess the reliability of predictive models for sex estimation based on permanent canine size. A systematic literature review was performed by following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA). Six electronic databases were searched as the primary source of information. As a secondary source of information, a manual search was performed to identify additional relevant studies not captured in the initial search. After assessing the methodological quality and risk of bias with the Joanna Briggs Institute Critical Appraisal Tools for Systematic Reviews, the data were subjected to statistical tests for a meta-analysis of diagnostic test accuracy and Higgin's I2 statistic to evaluate the heterogeneity between the eligible studies. The systematic search resulted in 21 studies for qualitative synthesis, and 13 of them were selected for quantitative analysis. The analysis of 25 univariate predictive models showed an estimated sensitivity of 77.2 % and specificity of 67.1 %. Meta-regression analyses were performed for dental arch, the type of diameter and dental region outcomes for these univariate predictive models. Dental arch (p = 0.029) and the dental region of measurement (p = 0.001) were significant modifiers. The analysis of 25 multivariate predictive models showed an estimated sensitivity of 82.6 % and specificity of 70.1 %. There were significant methodological limitations and substantial heterogeneity among the included studies. Based on the results, there is insufficient high-quality scientific evidence to support the safe use of predictive models based on permanent canine measurements as the exclusive method for sex estimation in forensic settings.

Utilising Discriminant Function Analysis (DFA) for Classifying Osteoarthritis (OA) Patients and Volunteers Based on Biomarker Concentration

Osteoarthritis (OA) is a degenerative joint disease characterised by the breakdown of cartilage, causing pain, stiffness, and limited movement. Early diagnosis is crucial for effective management but remains challenging due to non-specific early symptoms. This study explores the application of Discriminant Function Analysis (DFA) to classify OA patients and healthy volunteers based on biomarker concentrations of Interleukin-6 (IL-6), Tumour necrosis factor-alpha (TNF-α), and Myeloperoxidase (MPO). DFA was employed to analyse biomarker data from 86 participants (58 patients, 28 volunteers) to evaluate the discriminatory power of these biomarkers in predicting OA. Significant differences were observed in MPO and TNF-α levels between groups, while IL-6 did not show a significant distinction. The iterative classification process improved model assumptions and classification accuracy, achieving a pre-classification accuracy of 71.8%, which adjusted to 57.1% post-classification. The results highlight DFA's potential in OA diagnosis, suggesting its utility in managing complex data and aiding personalised treatment strategies. The study underscores the need for larger sample sizes and additional biomarkers to enhance diagnostic robustness and provides a foundation for integrating DFA into clinical practice for early OA detection.

Forensic evaluation of craniometric characteristics of the Kazakhstan population

Background

The human skull is the part of the skeleton most frequently used in population studies, as it was more exposed to genetic factors and less exposed to environmental factors. The skull is an important component in human forensic identification.

Materials and methods

The craniometric characteristics of 186 male and 114 female skulls found on the territory of Kazakhstan were studied. Dimensions were measured using standard anthropometric methods and instruments. The results of measurements of 25 craniometric parameters are presented. Methods of descriptive and parametric statistics were used.

Results

Statistical analysis showed significant regional dimorphism, confirming theindividuality of the Kazakhstan population. Statistically significant deviations werefound in 6 male craniometric characteristics and 4 female craniometric characteristics(p<0.05). The most dimorphous variables for regional identification in Kazakhstanmales were the higher skull base and frontal chord width , full face height , condylarand bigonial width , and low mandibular body reference values (p<0.05). For females,significant statistical discrepancies were seen in the transverse diameter and skullbase width, mastoid and occipital aperture width (p<0.05).

Conclusion

The recorded variations and changes in the morphology of the humanskull of the population of Kazakhstan indicate the need to develop and updateosteometric standards used in practice for specific populations. All this will significantlyimprove the accuracy of forensic identification and more fully study the biologicalpatterns of population formation, as well as evaluate the comparative effectiveness ofindividual features in the reconstruction of the population history of various populationgroups.

Metric evaluation of the anterior nasal spine to estimate sex and population group in South African individuals

INTRODUCTION

The anterior nasal spine is a pointed, midline projection of the maxilla. This bony structure dictates the overlying soft tissues providing the phenotypic features of the nose and upper lip and determines the differences in the mid-face morphology. Little data is available on the metric features of the Anterior nasal spine (ANS). This study aimed to perform metric evaluations of the ANS of white and black South African males and females to ascertain if morphological variations exist and if the differences are viable for the use in sex and population identification.

MATERIALS AND METHODS

The sample included 100 CBCT images for each population and sex group. Linear and angular measurements of the ANS were recorded in both the sagittal and axial planes.

RESULTS

Classification decision trees (pruned) were fitted to ascertain the relationship between population group, sex and the ANS measurements including and excluding age. For population group, all the ANS measurements were statistically significant for females but in males, all the ANS measurements were significant when performed individually. However, when fitted to the classification tree, Sagittal 2 did not show any statistical significance. When considering sex, only 2 of the ANS measurements (Sagittal 2 and Axial 1) were found to be significant. The results did not differ significantly when comparing the decision trees including and excluding age.

CONCLUSIONS

White South African individuals presented with a longer ANS that produced a more acute angle whereas black South African individuals presented with a shorter ANS and a more obtuse angle. Additionally, males presented with a longer ANS compared to females. ANS measurements were found to be more relevant for population discernment than for sex.

Gender Determination Using Index and Ring Finger Linear Measurements in North Indian Population: A Cross-Sectional Study

BACKGROUND

In the fields of medico-legal matters and bio-archaeological settings, gender evaluation plays a pivotal role in the initial stages of human identification. Approximately half of the population at risk is excluded when gender is determined, making it the most essential factor for identification. When it comes to medico-legal matters and bio-archaeological settings, gender evaluation is a crucial initial step in human identification. Traditional gender determination procedures, such as skull and pelvic analysis, may be hindered by fragmentary human remains that have been degraded by various forms of inhumation or physical assaults.

AIM

To investigate sexual dimorphism, this study examined the ratio of index finger length to ring finger length.

MATERIALS AND METHOD

The lengths of the index and ring fingers were measured and the ratios between them were calculated for both hands separately. Applications of IBM SPSS Statistics for Windows, Version 16.0 (Released 2007; IBM Corp., Armonk, New York, United States) included Student's t-test and Levene's test.

RESULTS

According to the study, women's index finger-to-ring finger length ratios were much longer than men's. The ratio of index finger to ring finger length was significantly different between the sexes on both sides of the hand (p<0.001). In terms of the right hand, the threshold value was 0.9666 for men and 0.9952 for females, while in terms of the left hand, the values were 0.9638 and 0.9920, respectively.

CONCLUSION

With an advancing front in this arena on gender determination, the use of digits has become an additional source of support to physical anthropologists for bio-archaeological surveys and to forensic experts for use in medico-legal investigations for fragmentary remains received during investigatory trials.

Age estimation from mandibles in Malay: A 2D geometric morphometric analysis

Objectives

In this study, the sizes and forms of mandibles in various age groups of the Malay population were measured and compared.

Methods

Geometric morphometric (GM) analysis of mandibles from 400 dental panoramic tomography (DPT) specimens was conducted. The MorphoJ program was used to perform generalized Procrustes analysis (GPA), Procrustes ANOVA, principal component analysis (PCA), discriminant function analysis (DFA), and canonical variate analysis (CVA). In the tpsDig2 program, the 27 landmarks were applied to the DPT radiographs. Variations in mandibular size and form were categorized into four age groups: group 1 (15-24 years), group 2 (25-34 years), group 3 (35-44 years), and group 4 (45-54 years).

Results

The diversity in mandibular shape among the first eight principal components was 81%. Procrustes ANOVA revealed significant shape differences (P < 0.001) among age groups. Mahalanobis distances indicated substantial differences among all age groups; group 1 and group 4 scored highest, at 2.114. The ranges for the cross-validation and discriminant function tests were 90-72% and 81-49%, respectively.

Conclusion

GM analysis through radiography is a simple, non-invasive, and non-destructive method of estimating age by using the mandible. GM analysis is unique because it can visualize the changes in mandible shape among age groups. This method should aid in age identification in forensic odontology investigations.

Sex Determination Using Frontal Sinus Diameters on Direct Radiography

BACKGROUND AND AIM

The shape and developmental stages of the frontal sinus (FS) differ in each individual, it can be used to determine sex and identity. This study aimed to assess the morphological structure of the FS diameters in sex determination using posterioanterior (AP) skull radiography. This data can be valuable for identifying and characterizing human features.

METHODS

The study included 350 patients (171 females, 179 males) aged between 20 and 55 years who underwent AP skull radiography. FSs were classified as symmetrical, asymmetrical, unilateral, or bilateral aplasic. The right and left FS height and width measurements were made based on the largest diameters.

RESULTS

The mean age was 32.8±11.45 years for the whole sample. The mean age of the males was 31.23±11.9 (20-51) years and that of the females was 34.45±10.75 (20-55) years. When classified anatomically, 20 patients had bilateral aplasia (12 males, eight females), 19 patients had right aplasia (10 males, nine females), and 11 patients had left aplasia (seven males, four females). FS was symmetrical in 206 (72.1%) patients while right dominance was observed in 33 (9.43%) patients and left dominance in 61 (17.43%) patients. The FS height and width values on both sides ​​were statistically significantly higher in males than in females (p<0.001 for each parameter). The females were accurately classified at a rate of 71.2% and the males at 68.2%.

CONCLUSION

Notably, our research has revealed that frontal sinus diameters are consistently larger in males than in females, and that direct radiography can be employed for gender determination with an accuracy rate of 69.7%. This information underscores the utility of morphometric evaluation of the frontal sinus diameters on direct radiography for gender and identity determination, potentially in conjunction with other parameters. In conclusion, our study has demonstrated the potential of the morphological structure of the frontal sinuses as a valuable tool for identifying and characterizing human individuals.

Understanding the burden of unidentified bodies: a systematic review

While human identification is a crucial aspect of medico-legal investigations, many individuals remain unidentified each year across the world. The burden of unidentified bodies is often referred to when motivating for improved methods of identification, and anatomical teaching, yet the actual burden is somewhat unclear. A systematic literature review was undertaken to identify articles that empirically investigate the number of unidentified bodies experienced. Despite the large number of articles returned, an alarmingly low number (24 articles) provided specific and empirical details on the number of unidentified bodies, demographics and trends thereof. It is possible that this lack of data is due to the variable definition of 'unidentified' bodies and the use of alternative terminology such as 'homelessness' or 'unclaimed' bodies. Nevertheless, the 24 articles provided data for 15 forensic facilities across ten countries of both developed and developing statuses. On average, developing countries experienced more than double (9.56%) the number of unidentified bodies when compared to developed nations (4.40%). While facilities were mandated under different legislations and infrastructures available varied greatly, the most common issue faced is the lack of standardised procedures for forensic human identification. Further to this, the need for investigative databases was highlighted. Through addressing the standardisation of identification procedures and terminology, alongside the appropriate utilisation of existing infrastructure and database creation, the number of unidentified bodies could be significantly reduced globally.

Population affinity estimation on a Spanish sample: Testing the validity and accuracy of cranium and mandible online software methods

Population affinity estimation is an important step in the identification of unknown individuals. To ensure accurate results, validation studies of newly developed methods must be performed using different target populations and skeletal elements. This research aimed to determine the accuracy and reliability of population affinity estimation on a modern Spanish sample using two online software applications. The sample consisted of 114 adult individuals (51 males, 63 females) using 38 measurements and one angle from the skull and mandible. AncesTrees was used for craniometric measurements and (hu)MANid for mandibular variables with different classification models and probability thresholds being evaluated. The required parameters were inputted for each individual and statistics were generated to assess the accuracy of the estimation. AncesTrees performed with the greatest accuracy as the program correctly classified the sample as Southwestern European or European, with highest accuracies being 54.56% (trial 1), 86.05% (trial 2), 82.61% (trial 3), 34.55% (trial 4) and 100% (trial 5). (hu)MANid correctly classified the sample as being from white origin with accuracies ranging from 70.59% to 80% without considering correct sex estimation, while accuracy ranged between 62.75% and 80% accounting for estimated sex. Population affinity estimation may determine subsequent methods used in the construction of the biological profile. Our results demonstrated varying accuracy rates depending on the element and method, offering a critical view in relation to software applicability and validity. Reference populations and intrinsic and extrinsic factors can potentially influence the method accuracy and reliability. Future research should focus on the inclusion of underrepresented groups.

Dental age estimation by cementum incremental lines counting: A systematic review and meta-analysis

The estimation of dental age by cementum incremental lines (CIL) is a widely investigated method; however, its reliability remains uncertain. The aim of this article was to assess whether CIL are a reliable biological indicator for estimating dental age. A search was performed in Embase, LILACS, PubMed/MEDLINE, SciELO, Scopus and Web of Science databases using a combination of terms related to the topic. Two independent reviewers used inclusion and exclusion criteria so that relevant articles were selected and evaluated. For the risk of bias analysis, a checklist from The Joanna Briggs Institute was applied. For the meta-analysis, Pearson's Correlation Coefficient between chronological age and estimated age was considered as an effect measure. The heterogeneity of studies was assessed using the Cochran's Q statistical test (p < 0.05), and the publication bias using the asymmetry of the Funnel plot and Egger's linear regression test (p < 0.05). Most selected articles had low risk of bias. Although not all studies were included in the meta-analysis, it demonstrated the presence of high heterogeneity among them. Despite this, the synthesized result indicated that the age estimated by CIL count has a high correlation with chronological age. Furthermore, the graphical analysis suggested the absence of publication bias, which was confirmed by the Egger's linear regression test. Therefore, there is scientific evidence that CIL are reliable in estimating dental age, but the method requires a standardized protocol to be followed, as well as the rigorous choice of the root area to be analyzed.

Assessment of the Possibilities of Forensic Identification Population of Kazakhstan by Craniometric Indicators

BACKGROUND: Craniometric indicators are one of the most reliable sources of information about the population. Despite the development of genetic methods, skull measurements are extremely important in anthropology and forensic medicine. In addition to the history of population development, environmental factors such as climate and lifestyle contribute to variations in human skull shape. Due to the high variability of human individuals, the anthropological study of the population is carried out selectively, with a comparison of different population groups (ethnic, professional, age, gender). The lack of clear ideas about the typical parameters and proportions of the skull among the people of Kazakhstan creates a certain gap in forensic-medical identification. AIM: The aim of the work is to check the hypothesis about the relationship between variations in skull morphology and changes in craniometric indicators with climatic conditions and the specifics of lifestyle in populations living in different territories of Kazakhstan. METHODS: 187 male and 114 female adult skulls found on the territory of the two largest regions of Kazakhstan were examined. The variable variability of 25 craniometric indicators of skulls found on the territory of Central and South Kazakhstan was studied. All osteometric changes were performed using standard anthropometric instruments, followed by the calculation of craniometric indices. Multidimensional statistics were applied. RESULTS: The two populations demonstrate differences in craniometric indicators formed in different geographical and ecological conditions, regardless of gender. It was found that the sizes of the skulls found in the two studied regions of Kazakhstan statistically significantly differ in 5 craniometric indicators for men and 8 craniometric indicators for women. Significant changes were noted in the size of the full and upper height of the face, the average width of the face, the height of the body of the lower jaw and the height of the nose in men.  The most dimorphic variables for forensic medical evaluation in the studied populations of female skulls were transverse, altitudinal and zygomatic diameters, mastoid width, width of the base of the skull, width of the occipital foramen, upper face height and nose height. The shape of the skulls found in the studied territories is predominantly brachycephalic. The cranial index was >81.1% - at men, 83% - at women. The study showed that race affects the size of the skull, regardless of gender. Craniometric parameters in male and female skulls vary according to different criteria. In women between races, there are statistically significant differences in the size of the width of the occipital foramen and the average width of the face. Statistically significant differences in the width of the base of the skull, the zygomatic diameter and the average width of the face between the Caucasoid and Mongoloid races were revealed in the studied regions in men. The established differences made it possible to form additional differential diagnostic criteria. CONCLUSION: Identification of the features inherent in the population living in certain territories provides auxiliary information for medical and forensic identification of a person. In this study, population-specific craniometric indicators have been developed for inhabitants of two regions of Kazakhstan, which expand and complement identification capabilities when categorizing skeletal remains found in these territories.

Simple linear regression approach for evaluating models to estimate stature based on upper limb dimensions of adult Bangladeshi males

Background

The stature of a living human reflects the nutritional, genetic, and disease patterns of individual experiences. This study adopted a simple linear regression method and R2 values to identify the preferred model for stature estimation based on the lengths of the arm, radius, ulna, and hand; breadth of the hand; and circumference of the wrist of the adult Bangladeshi male population. This cross-sectional study was performed in the Anatomy Department of Sir Salimullah Medical College, Dhaka, from January 2009 to June 2011. One hundred right-handed adult Muslim Bangladeshi males aged 25 to 45 years participated in the study.

Results

The regression model using right and left ulnar length explained 63% of the measured stature with the least standard error of the estimate (0.435 and 0.436), the model using left and right arm length explained 60%, the model using left and right radius length explained 51%, and the model using left- and right-hand length explained 44% of the measured stature. However, the models using left and right handbreadth and wrist circumference explained only 11 to 13% of the measured stature with a higher standard error of the estimate (6.66 to 6.73). For 25- to 45-year-old Bangladeshi Muslim males, the ulnar length of both sides was the best predictor of stature.

Conclusions

Linear regression equations in estimating stature effectively may encourage its application in future studies addressing different age groups, sexes, nutritional statuses, religions, and ethnicities of Bangladesh.

Postmortem Skeletal Microbial Community Composition and Function in Buried Human Remains

Bones and teeth can provide a lasting resource to identify human remains following decomposition. Bone can support dynamic communities of micro- and macroscopic scavengers and incidental taxa, which influence the preservation of bone over time. Previously we identified key microbial taxa associated with survivability of DNA in bones of surface-decomposed human remains, observing high intra- and interindividual variation. Here we characterized the postmortem bone microbiome of skeletal remains in a multi-individual burial to better understand subsurface bone colonization and preservation. To understand microbial community origins and assembly, 16S rRNA amplicon sequences from 256 bone and 27 soil samples were compared to bone from individuals who decomposed on the ground surface, and human gut sequences from the American Gut Project. Untargeted metabolomics was applied to a subset of 41 bone samples from buried remains to examine potential microbe–metabolite interactions and infer differences related to community functionality. Results show that postmortem bone microbial communities are distinct from those of the oxic surface soils and the human gut. Microbial communities from surface-deposited bone and shallow buried bone were more similar to those from soils, while bones recovered from saturated areas deeper in the grave showed increased similarity with human gut samples with higher representation of anaerobic taxa, suggesting that the depositional environment affected the established bone microbiome. Correlations between metabolites and microbes indicate that phosphate solubilization is likely an important mechanism of microbially mediated skeletal degradation. This research expands our knowledge of microbial bone colonizers, including colonizers important in a burial environment.

IMPORTANCE Understanding the microbes that colonize and degrade bone has important implications for preservation of skeletal elements and identification of unknown human remains. Current research on the postmortem bone microbiome is limited and largely focuses on archaeological or marine contexts. Our research expands our understanding of bone microbiomes in buried remains by characterizing the taxonomic and metabolic diversity of microbes that are colonizing bone after a 4-year postmortem burial interval and examines the potential impact of microbial colonization on human skeletal DNA preservation. Our results indicate that the postmortem bone microbiome is distinct from the human gut and soil. Evidence from combined metabolomic and amplicon sequencing analysis suggests that Pseudomonas and phosphate solubilization likely play a role in skeletal degradation. This work provides important insight into the types and activities of microbes controlling the preservation of buried skeletal remains.

Assessment of renal glomerulosclerosis and thickness of the carotid intima-media complex as a means of age estimation in Western European bodies

INTRODUCTION

The estimation of age-at-death of unidentified cadavers is a central aspect of the identification process. With increasing age, the incidence of glomerulosclerosis and the thickness of the carotid wall have been observed to also increase. This correlation has been demonstrated in various international histological studies. The aim of our study was to assess whether these correlations also apply to a Western European population.

METHODOLOGY

In this retrospective observational study, kidney and common carotid artery samples from 216 cases autopsied at the Institute of Legal Medicine at the Justus-Liebig University in Giessen, Germany, were examined. Only cases with available tissue samples from both body sides were included. Exclusion criteria were poor sample quality and an age younger than 21 years. After histological processing, the tissue samples were assessed and digitally evaluated. Regression and classification analyses were used to investigate the correlation between age-at-death and intima-media thickness and age-at-death and the incidence of renal glomerular sclerosis.

RESULTS

Of the 216 autopsy cases, 183 were included for evaluation. Analysis of the carotid artery segments showed a strong correlation (Pearson correlation coefficient r = 0.887) between the intima-media-complex thickness and chronological age. Classification of the glomerulosclerotic incidence showed a correlation of 37.7-43.1% with the predicted age group.

DISCUSSION

Both the intima-media thickness and the proportion of sclerotic glomeruli can be used to estimate age in Western European cadavers. On the basis of these results, both methods are suited to supplement other already established methods for age-at-death estimation in the identification of an unknown cadaver.

A full Bayesian calibration model for assessing age in adults by means of pulp/tooth area ratio in periapical radiography

The Bayesian approach is being a fundamental tool in forensic and legal field where inferences and decisions are made. In this study, a full Bayesian calibration model was developed to make probabilistic inferences about age estimation in a reference sample of 891 periapical X-rays of upper and lower canines. These teeth belonged to both deceased and living adult subjects, aged between 20 and 86 years, coming from five different countries (Turkey, Italy, Portugal, Japan and Mexico). For this purpose, the narrowing of pulp chamber due to the apposition of secondary dentine was analysed by means of the pulp/tooth area ratio. To determine the agreement of the method, intra- and inter-observer differences for measuring process were calculated by means of the intraclass correlation coefficient (ICC) analysis. Observer error tests showed excellent agreement between observers and between repeated assessments. According to the results of the ANCOVA, neither nationality nor sex was associated to the secondary dentine apposition while it is associated with individual's age. The results of the present study indicated that the concept of probability is intrinsically linked to the assessment of age in a forensic context, and the Bayesian approach could be considered a robust tool to overtake the bias generated by traditional regression models, thus helping the decision-making process in a legal framework.

Radiographic analysis of dental maturation in children with amelogenesis imperfecta: A case-control study

AIMS

To assess dental maturation in children with amelogenesis imperfecta (AI) and compare their estimated dental age with the age of non-AI children.

METHODS AND RESULTS

Panoramic radiographs of children with (n = 27) and without (n = 54) AI were retrospectively collected in the ratio of 1:2. The former consisted of case group, while the latter figured as control group. Both groups were paired by sex and age (P > .05). Dental maturation was assessed in each radiograph using Demirjian's staging technique and Willems' method. Intra- and interexaminer reproducibility reached >0.8. The mean estimated dental age in subjects with AI was 12.5 ± 2.69 years, while in subjects without AI it was 11.73 ± 2.48 years (P = .21). The comparison of mean chronological (12.26 ± 2.6 years) and estimated dental age (12.5 ± 2.69 years) in subjects with AI did not reveal statistically significant differences (P = .38).

CONCLUSION

This study highlights the similarity of dental maturation between subjects with and without AI from the radiographic perspective of crown-root formation.

Evolution of Forensic Anthropological Methods of Identification

Forensic identification of human remains has long been a core contribution of forensic anthropologists to death investigations. The array and scientific robusticity of the identification methods employed by the anthropologist has evolved in the last several decades, and as with other nonidentification methods, anthropologists have embraced the progression toward the use of validated and statistically defensible methods for identification. This article presents an overview of the role that the forensic anthropologist plays in the identification of human remains and the evolution of anthropological methods of identification.

The Forensic Anthropologist in the Mass Fatality Context

Mass fatality incidents require a multi-agency, multidisciplinary response to effectively and efficiently manage the recovery and identification of human remains. The forensic anthropologist is uniquely suited for a significant role in the disaster response, demonstrated in the recovery and triage of human remains, interpretation of skeletal trauma, and identification of victims. However, the majority of published literature discusses these response operations in the context of large-scale incidents with significant numbers of highly fragmented and commingled human remains, which does not reflect the operational reality of mass fatality incidents in the United States. This article provides a realistic definition of the term "mass fatality incident" for medicolegal jurisdictions and provides the contributions of the forensic anthropologist for all types of incidents.