Testing the accuracy of the DRNNAGE software for age estimation in a modern Greek sample.

Estimation of age-at-death from human skeletal remains is fundamental in forensic anthropology as part of the construction of the biological profile of the individual under study. At the same time, skeletal age-at-death estimation in adults is problematic due to the disparity between chronological and biological age, the important inter-individual variability at the rate of skeletal aging, and inherent biases in the available methodologies (e.g., age mimicry). A recent paper proposed a method for skeletal age-at-death estimation based on multiple anatomical traits and machine learning. A software was also created, DRNNAGE, for the easy implementation of this method. The authors of that study supported that their methods have very high repeatability and reproducibility, and the mean absolute error of the age estimation was ~6 years across the entire adult age span, which is particularly high and promising. This paper tests the proposed methodology on a modern documented Greek sample of 219 adult individuals from the Athens Collection, with age-at-death from 19 to 99 years old. The sample was split into males and females as well as into individuals under and over 50 years old. We also divided the sample in 10-year intervals. First, intra- and inter-observer error was estimated in order to assess repeatability and reproducibility of the variables employed for age-at-death estimation. Then, the validity (correct classification performance) of DRNNAGE for each anatomical region individually, as well as all combined, was evaluated on each demographic separately and on the pooled sample. According to the results, some of the variables showed very low repeatability and reproducibility, thus their use should be cautious. The DRNNAGE software showed overall highly accurate age-at-death estimates for individuals older than 50 years, but poor on younger adults, with only exception the cranial sutures, which performed surprisingly well for all age groups. Overall, these results support the importance of cross-validation and the use of population-specific methods in forensic anthropology.

Inter-population differences in acetabular senescence: relevance in age-at-death estimation.

Since investigation of the timing of the skeletal traits among the acetabula of different populations is lacking, this study aims to evaluate the relevance of geographical origin in the acetabulum aging process and in the usability of the SanMillán-Rissech aging method. The acetabula of 826 European North Americans derived from the Bass Collection (USA) have been analyzed and compared with 611 Portuguese acetabula from the Luis Lopes Collection (Portugal) applying the most updated acetabular age estimation technique (2017). After evaluating and comparing the acetabular aging rates between both populations by Mann-Whitney U tests, the inaccuracy values (bias and absolute error) were analyzed and compared using population-specific reference samples and using references differing in geographical origin by Wilcoxon tests. In general terms, the North Americans age faster than the Portuguese, especially the females, reaching the consecutive acetabular stages at younger ages. Regarding the SanMillán-Rissech method accuracy, using population-specific reference samples produces, as a general rule, better outcomes. In addition, an exhaustive meta-analysis of inaccuracy values has demonstrated that this method provides better estimation values than pubic symphysis and auricular surfaces regardless of the geographic coherence of the reference sample. These inter-population skeletal differences are derived from different factors than age, highlighting the impact of both biological and social background on age estimation. A thorough analysis of the skeletal age-based timing becomes essential to understanding, deciphering and being able to minimize bias and potential inaccuracy or even counteract them when applying the age estimation methods to different populations.

Performance of three mathematical models for estimating age-at-death from multiple indicators of the adult skeleton.

The mathematical method which will achieve the most accurate and precise age-at-death estimate from the adult skeleton is often debated. Some research promotes Bayesian analysis, which is widely considered better suited to the data construct of adult age-at-death distributions. Other research indicates that methods with less mathematical complexity produce equally accurate and precise age-at-death estimates. One of the advantages of Bayesian analysis is the ability to systematically combine multiple indicators, which is reported to improve the age-at-death estimate. Few comparisons exist between Bayesian analysis and less complex mathematical models when considering multiple skeletal indicators. This study aims to evaluate the performance of a Bayesian approach compared to a phase-based averaging method and linear regression analysis using multiple skeletal indicators. The three combination methods were constructed from age-at-death data collected from 330 adult skeletons contained in the Raymond A Dart and Pretoria Bone Collections in South Africa. These methods were tested and compared using a hold-out sample of 30 skeletons. As is frequently reported in literature, a balance between accuracy and precision was difficult to obtain from the three selected methods. However, the averaging and regression analysis methods outperformed the Bayesian approach in both accuracy and precision. Nevertheless, each method may be suited to its own unique situation-averaging to inform first impressions, multiple linear regression to achieve statistically defensible accuracies and precisions and Bayesian analysis to allow for cases where category adjustments or missing indicators are necessary.

Human Bone Proteomes before and after Decomposition: Investigating the Effects of Biological Variation and Taphonomic Alteration on Bone Protein Profiles and the Implications for Forensic Proteomics.

Bone proteomic studies using animal proxies and skeletonized human remains have delivered encouraging results in the search for potential biomarkers for precise and accurate post-mortem interval (PMI) and the age-at-death (AAD) estimation in medico-legal investigations. The development of forensic proteomics for PMI and AAD estimation is in critical need of research on human remains throughout decomposition, as currently the effects of both inter-individual biological differences and taphonomic alteration on the survival of human bone protein profiles are unclear. This study investigated the human bone proteome in four human body donors studied throughout decomposition outdoors. The effects of ageing phenomena (in vivo and post-mortem) and intrinsic and extrinsic variables on the variety and abundancy of the bone proteome were assessed. Results indicate that taphonomic and biological variables play a significant role in the survival of proteins in bone. Our findings suggest that inter-individual and inter-skeletal differences in bone mineral density (BMD) are important variables affecting the survival of proteins. Specific proteins survive better within the mineral matrix due to their mineral-binding properties. The mineral matrix likely also protects these proteins by restricting the movement of decomposer microbes. New potential biomarkers for PMI estimation and AAD estimation were identified. Future development of forensic bone proteomics should include standard measurement of BMD and target a combination of different biomarkers.

Correlation of the human pubic symphysis surface with age-at-death: a novel quantitative method based on a bandpass filter.

Age-at-death estimation from skeletal remains typically utilizes the roughness of pubic symphysis articular surfaces. This study presents a new quantitative method adapting a tool from geometric morphometrics, bandpass filtering of partial warp bending energy to extract only age-related changes of the surfaces. The study sample consisted of 440 surface-scanned symphyseal pubic bones from men between 14 and 82 years of age, which were landmarked with 102 fixed and surface semilandmarks. From the original sample, 371 specimens within Procrustes distance of 0.05 of the side-specific average were selected. For this subsample, age was correlated with total bending energy (calculated as summed squared partial warps amplitudes) for a wide range of plausible bandpass filters. For our subsample's 188 right-side surfaces, the correlation between age and bandpass filtered versions of bending energy peaks relatively sharply at r = -0.648 for ages up through 49 years against the first seven partial warp amplitudes only. The finding for left symphyses is similar. The results demonstrate that below the age 50, the symphyseal surface form changes most systematically related to age may be best detected by a lowpass-filtered version of bending energy: signals at the largest geometric scales of roughness rather than its full spectrum. Combining this method with information from other skeletal features could further improve age-at-death estimation based on the symphyseal pubic surface.

Technical note: preliminary insight into a new method for age-at-death estimation from the pubic symphysis.

Age-at-death estimation methods are important in forensic anthropology. However, age assessment is problematic due to inter-individual variation. The subjectivity of visual scoring systems can affect the accuracy and reliability of methods as well. One of the most studied skeletal regions for age assessment is the pubic symphysis. Few studies on Spanish pubic symphysis collections have been conducted, making further research necessary as well as the sampling of more forensic skeletal collections. This study is a preliminary development of an age-at-death estimation method from the pubic symphysis based on a new simple scoring system. A documented late twentieth century skeletal collection (N = 29) and a twenty-first century forensic collection (N = 76) are used. Sixteen traits are evaluated, and a new trait (microgrooves) is described and evaluated for the first time in this study. All traits are scored in a binary manner (present or absent), thus reducing ambiguity and subjectivity. Several data sets are constructed based on different age intervals. Machine learning methods are employed to evaluate the scoring system's performance. The results show that microgrooves, macroporosity, beveling, lower extremity, ventral and dorsal margin decomposition, and lipping are the best preforming traits. The new microgroove trait proves to be a good age predictor. Reliable classification results are obtained for three age intervals (≤ 29, 30-69, ≥ 70). Older individuals are reliably classified with two age intervals (< 80, ≥ 80). The combination of binary attributes and machine learning algorithms is a promising tool for gaining objectivity in age-at-death assessment.

Identifying Methylation Patterns in Dental Pulp Aging: Application to Age-at-Death Estimation in Forensic Anthropology.

Age-at-death estimation constitutes one of the key parameters for identification of human remains in forensic investigations. However, for applications in forensic anthropology, many current methods are not sufficiently accurate for adult individuals, leading to chronological age estimates erring by ±10 years. Based on recent trends in aging studies, DNA methylation has great potential as a solution to this problem. However, there are only a few studies that have been published utilizing DNA methylation to determine age from human remains. The aim of the present study was to expand the range of this work by analyzing DNA methylation in dental pulp from adult individuals. Healthy erupted third molars were extracted from individuals aged 22-70. DNA from pulp was isolated and bisulfite converted. Pyrosequencing was the chosen technique to assess DNA methylation. As noted in previous studies, we found that ELOVL2 and FHL2 CpGs played a role in age estimation. In addition, three new markers were evaluated-NPTX2, KLF14, and SCGN. A set of CpGs from these five loci was used in four different multivariate regression models, providing a Mean Absolute Error (MAE) between predicted and chronological age of 1.5-2.13 years. The findings from this research can improve age estimation, increasing the accuracy of identification in forensic anthropology.

Application of the recent SanMillán-Rissech acetabular adult aging method in a North American sample.

Recently, a renewed acetabular aging methodology was published by San-Millán et al. (Int J Leg Medicine, 47, 131: 501-525), refining the variables associated with acetabular fossa aging in different populations. Due to its novelty, this method has not yet been examined in any other population, other than it was developed and originally tested on. Therefore, the main goals of this study are two-fold: (1) to evaluate the accuracy of SanMillán-Rissech's method in a North American sample made up of 826 white (456 males and 370 females) individuals from the Bass Collection and (2) to determine whether the revised methodology shows higher rates of accuracy than the original methodology (J Forensic Sci, 31, 51(2): 213-229). Scores obtained by both methodologies were analyzed via a Bayesian statistical program (IDADE2) that estimates a relative likelihood distribution for the target individuals, produces age-at-death estimates, and provides 95% confidence intervals. Even though the revised method was developed using a Western European collection, the results demonstrate that it is also applicable to North American samples with reasonable accuracy results, i.e., an average absolute error of 7.19 years in males and 9.65 years in females. However, accuracy in females is significantly lower than in males, likely due to their higher morphological variability associated with different factors other than age. The significantly better performance of the revised methodology compared with the original is also been confirmed by the current findings from this North American sample, supporting the renewed system as a better aging methodology. Although work on further populations is needed, previously and current results should encourage professionals to include the acetabular method in forensic and archaeological laboratories routines.

Age at death estimation by cementochronology: Too precise to be true or too precise to be accurate?

OBJECTIVES: Cementochronology based on annual deposition of acellular cementum is acknowledged for its superior performance for estimating age-at-death but is also disregarded because of its suspicious effectiveness. This article aims to provide a standardized framework for the validation of the technique and to define and test cementochronology's performance and limitations. MATERIALS AND METHODS: To determine the boundaries of the cementum aging technique, we applied a certified protocol on a sample of 200 healthy canines from individuals of known age, sex, postmortem, and inhumation intervals from anthropological and anatomical collections. We scored readability and preservation of cementum and measured the agreement between estimates, i.e., the precision, and assessed the quality of the accordance between estimates and chronological age, i.e., the accuracy. To investigate the applicability on ancient material, 200 additional canines extracted from archeological assemblages were included. Accuracy and precision were analyzed for each age group in considering postmortem intervals and taphonomical conditions. RESULTS: A strong correlation was found between chronological age and estimates (r = .927; p = .000) but results reveal an association between readability of incremental lines and chronological age (p < .05) and a notable difference in both precision and accuracy between individuals under and over 50 years. Results also demonstrate that taphonomy can be a serious obstacle increasing imprecision by a factor of three. DISCUSSION: Improperly adopted, cementochronology can lead to precise but inaccurate estimations. If methodological, physiological, and taphonomical factors are taken into account, then, and only then, cementochronology will serve as a versatile and powerful tool for age-at-death estimation.

A test and analysis of Calce (2012) method for skeletal age-at-death estimation using the acetabulum in a modern skeletal sample.

In forensic anthropology, the age-at-death of an adult individual is one of the most complex parameters of the biological profile to estimate. The present study aims to evaluate the reliability of the Calce (2012) method for the estimation of age-at-death through acetabulum changes in a sample of Portuguese origin. This method consists of the global analysis of acetabular age-related morphology with focus on three specific traits, namely the acetabular groove, the osteophyte development of the acetabular rim, and the apex growth. This method was tested in 120 individuals sampled from the Twenty-first Century Identified Skeletal Collection (University of Coimbra, Portugal). The test sample is composed of 60 males and 60 females, aged between 25 and 99 years, with well-preserved os coxae. The results showed that only 60% of the individuals were correctly attributed to the age group defined by the technique. The comparison with previous studies in other populations shows significant inter-population differences in the relationship between the acetabulum variables used by Calce and age-at-death. The obtained results advise caution in the use of the Calce (2012) method to estimate the age-at-death of unidentified skeletons.

Toward the adoption of cementochronology in forensic context.

Because acellular dental cementum is considered to be formed continually throughout life and to not undergo remodeling processes, cementochronology is considered to be a method with the potential for directly assessing chronological age. Considering that most previous studies on humans have assumed the superior performance of this method, it is surprising that this technique is not more widely adopted in anthropology. To understand this controversy, we highlight that there is no standardized procedure for sample preparation. The numerous technical approaches that exist impact the reliability of the method, and the recent creation of an international work group (Cementochronology Research Program) demonstrates the need for researchers to share their experience to overcome these obstacles. This paper aims to address this paradox by debating the aspects that contribute to the limited use of this method and by illustrating its potential through an application on forensic cases. A protocol, which was recently certified according to the ISO-9001, was applied to nine anthropological cases from the Forensic Medicine Institute of Lille (northern France) and compared with routine osteological and dental methods. The results show that traditional methods matched the known age due to the wide extent of their range, while the accuracy and precision of cementochronological estimates was also notable. This paper establishes that cementochronology may serve as a particularly important tool for age estimation for forensic anthropologists and should, at least, be used in addition to other methods.

Age-at-Death Estimation for Modern Populations in Mexico and Puerto Rico through the Use of 3D Laser Scans of the Pubic Symphysis.

Reliable age-at-death estimates from the adult skeleton are of fundamental importance in forensic anthropology, because it contributes to the identity parameters used in a medicolegal death investigation. However, reliable estimates are difficult because many traditional aging methods depend on a set of population-specific criteria derived from individuals of European and African descent. The absence of information on the potential differences in the aging patterns of underrepresented, especially Latinx, populations may hinder our efforts to produce useful age-at-death estimates. In response to these concerns, this study explores the utility of currently available aging techniques and whether population-specific aging methods among Latinx groups are needed. The authors obtained data from two skeletal collections representing modern individuals of Mexican and Puerto Rican origin. They examined five newly developed computational shape-based techniques using 3D laser scans of the pubic symphysis and one traditional bone-to-phase technique. A validation test of all computational and traditional methods was implemented, and new population-specific equations using the computational algorithms were generated and tested against a subsample. Results suggest that traditional and computational aging techniques applied to the pubic symphysis perform best with individuals within 35-45 years of age. Levels of bias and inaccuracy increase as chronological age increases, with overestimation of individuals younger than 35 years and underestimation of individuals older than 45 years. New regression models provided error rates comparable to, and in some occasions outperformed, the original computational models developed on white American males, but age estimates did not significantly improve. This study shows that population-specific models do not necessarily improve age estimates in Latinx samples. Results do suggest that computational methods can ultimately outperform the Suchey-Brooks method and provide improved objectivity when estimating age at death in Latinx samples.

Testing inter-observer reliability of the Transition Analysis aging method on the William M. Bass forensic skeletal collection.

OBJECTIVES: Skeletal age estimation is an integral part of the biological profile. Recent work shows how multiple-trait approaches better capture senescence as it occurs at different rates among individuals. Furthermore, a Bayesian statistical framework of analysis provides more useful age estimates. The component-scoring method of Transition Analysis (TA) may resolve many of the functional and statistical limitations of traditional phase-aging methods and is applicable to both paleodemography and forensic casework. The present study contributes to TA-research by validating TA for multiple, differently experienced observers using a collection of modern forensic skeletal cases. MATERIALS AND METHODS: Five researchers independently applied TA to a random sample of 58 documented individuals from the William M. Bass Forensic Skeletal Collection, for whom knowledge of chronological age was withheld. Resulting scores were input into the ADBOU software and maximum likelihood estimates (MLEs) and 95% confidence intervals (CIs) were produced using the forensic prior. Krippendorff's alpha was used to evaluate interrater reliability and agreement. Inaccuracy and bias were measured to gauge the magnitude and direction of difference between estimated ages and chronological ages among the five observers. RESULTS: The majority of traits had moderate to excellent agreement among observers (≥0.6). The superior surface morphology had the least congruence (0.4), while the ventral symphyseal margin had the most (0.9) among scores. Inaccuracy was the lowest for individuals younger than 30 and the greatest for individuals over 60. Consistent over-estimation of individuals younger than 30 and under-estimation of individuals over 40 years old occurred. Individuals in their 30s showed a mixed pattern of under- and over-estimation among observers. DISCUSSION: These results support the use of the TA method by researchers of varying experience levels. Further, they validate its use on forensic cases, given the low error overall.

Cortical bone histomorphology of known-age skeletons from the Kirsten collection, Stellenbosch university, South Africa.

OBJECTIVES: Normal human bone tissue changes predictably as adults get older, but substantial variability in pattern and pace remains unexplained. Information is needed regarding the characteristics of histological variables across diverse human populations. METHODS: Undecalcified thin sections from mid-thoracic ribs of 213 skeletons (138 M, 75 F, 17-82 years, mean age 48 years), are used to explore the efficacy of an established age-at-death estimation method and methodological approach (Cho et al.: J Forensic Sci 47 (2002) 12-18) and expand on it. The ribs are an age-balanced sample taken from skeletonized cadavers collected from 1967 to 1999 in South Africa, each with recorded sex, age, cause of death and government-defined population group (129 "Colored," 49 "Black," 35 "White"). RESULTS: The Ethnicity Unknown equation performs better than those developed for European-Americans and African-Americans, in terms of accuracy and bias. A new equation based solely on the study sample does not improve accuracy. Osteon population densities (OPD) show predicted values, yet secondary osteon areas (On.Ar) are smaller than expected for non-Black subgroups. Relative cortical area (Ct.Ar/Tt.Ar) is low among non-Whites. CONCLUSIONS: Results from this highly diverse sample show that population-specific equations do not increase estimate precision. While within the published range of error for the method (±24.44 years), results demonstrate a systematic under-aging of young adults and over-aging of older adults. The regression approach is inappropriate. The field needs fresh approaches to statistical treatment and to factors behind cortical bone remodeling.

Evaluation of the forAge Age-at-Death Estimation Program Using Pubic Symphyseal Surface in a Korean Population.

The forAge program estimates the age-at-death of human pubic symphysis using 3-dimensional scans. It was developed by Dennis E. Slice and Bridget F. B. Algee-Hewitt, and utilizes three distinct scores: the Slice and Algee-Hewitt (SAH) score, bending energy (BE), and ventral curvature (VC). However, these scores and age estimation regression equation were obtained through European American pubic symphysis. Changes in the pubic symphysis surface are evaluated as one of the most reliable indicators for estimating age, but in connection with this, using Korean materials, changes in the pubic symphysis surface and the actual changes are evaluated. There is no bar where the relationship between ages is grasped, and there are cases where a methodology developed for a specific group is applied to a Korean group. Changing the pubic symphysis surface by aging was evaluated as one of the most reliable indicators for estimating age. However, there is no study conducted on the relationship between changes in the pubic symphysis and actual age and applied the age estimation method for a specific population among Korean population. The purpose of this study is to compare the difference between the actual age and the estimated age in Korean to see if the forAge program is applicable to other population of different ancestral origin. One hundred and four modern Korean pubic symphyseal surfaces (47 to 96 years old) were used in this study. Through the pubic symphyseal surface 3-dimensional images, age-at-death was estimated via prediction equation and new regression lines using SAH, VC, and BE scores. Firstly, the estimated age via prediction equation using the first version of SAH score was lower than the actual age according to all pubic symphyseal surfaces for those older than 56. With aging, the difference between the actual age and estimated age became markedly larger. Secondly, the estimated ages via the new regression lines using VC, the second version of SAH score, and BE were shown a similar pattern to the previous prediction equation. The current study explored the applicability of a quantitative method using pubic symphyseal surface for age estimation in a modern Korean population. This study showed the forAge program cannot be applied to a modern Korean population, as they present relatively low correlations with the actual age-at-death.

Application of machine-learning methods in age-at-death estimation from 3D surface scans of the adult acetabulum.

OBJECTIVE: Age-at-death estimation is usually done manually by experts. As such, manual estimation is subjective and greatly depends on the past experience and proficiency of the expert. This becomes even more critical if experts need to evaluate individuals with unknown population affinity or with affinity that they are not familiar with. The purpose of this study is to design a novel age-at-death estimation method allowing for automatic evaluation on computers, thus eliminating the human factor. METHODS: We used a traditional machine-learning approach with explicit feature extraction. First, we identified and described the features that are relevant for age-at-death estimation. Then, we created a multi-linear regression model combining these features. Finally, we analysed the model performance in terms of Mean Absolute Error (MAE), Mean Bias Error (MBE), Slope of Residuals (SoR) and Root Mean Squared Error (RMSE). RESULTS: The main result of this study is a population-independent method of estimating an individual's age-at-death using the acetabulum of the pelvis. Apart from data acquisition, the whole procedure of pre-processing, feature extraction and age estimation is fully automated and implemented as a computer program. This program is a part of a freely available web-based software tool called CoxAGE3D, which is available at https://coxage3d.fit.cvut.cz/. Based on our dataset, the MAE of the presented method is about 10.7 years. In addition, five population-specific models for Thai, Lithuanian, Portuguese, Greek and Swiss populations are also given. The MAEs for these populations are 9.6, 9.8, 10.8, 10.5 and 9.2 years, respectively. Our age-at-death estimation method is suitable for individuals with unknown population affinity and provides acceptable accuracy. The age estimation error cannot be completely eliminated, because it is a consequence of the variability of the ageing process of different individuals not only across different populations but also within a certain population.

Predicting chronological age based on age-related osteophyte development in the superior and inferior vertebral centrum margins of T12-L5.

The purpose of this study was to determine the relationship between vertebral margins at individual vertebral levels between T12-L5 vertebra and chronological age and develop predictive models. Three hundred and nineteen CT scans from a medical imaging database in North America were randomly selected. Three superior and inferior vertebral margin sites were scored based on observable age-related changes. All individual vertebral margin site scores significantly correlated with age at death with Pearson r values ranging from 0.47 to 0.77. Totaling the individual vertebral margin site scores for L1-L5 improved Pearson r to 0.92. All resulting predictive models were significant, and the best models predicted age at death within 10 years 70%-76% of the time for males, females, and combined male and females. In conclusion, this study produced accurate and reliable models to predict age at death using age-related changes in the spine for a North American population.

Technical note: Interest of focused fields in post-mortem computed tomography using photorealistic images for age at death estimation from the pubic symphysis.

INTRODUCTION: The morphological assessment of the pubic symphysis using the Suchey-Brooks method is considered a reliable age at death indicator. Age at death estimation methods can be adapted to the images obtained from post-mortem computed tomography (PMCT). The aim of this study is to evaluate the utility of pubic symphysis photorealistic images obtained through Global illumination rendering (GIR) for age at death estimation from whole-body PMCT and from focused PMCT on the pubic bone. MATERIALS AND METHODS: We performed virtual age at death estimation using the Suchey Brooks method from both the whole-body field of view (Large Field of View: LFOV) and the pubis-focused field of view (Small and Field of View: SFOV) of 100 PMCT. The 3D photorealistic images were evaluated by three forensic anthropologists and the results were statistically evaluated for accuracy of the two applied PMCT methods and the intra- and inter-observer errors. RESULTS: When comparing the two acquisitions of PMCT, the accuracy rate reaches 98.5% when using a pubic-focused window (SFOV) compared to 86% with a whole-body window (LFOV). Additionally, the intra- and inter-observer variability has demonstrated that the focused window provides better repeatability and reproducibility. CONCLUSION: Adding a pubic-focused field of view to standard PMCT and processing it with GIR appears to be an applicable technique that increases the accuracy rate for age at death estimation from the pubic symphysis.

Automated age-at-death estimation from 3D surface scans of the facies auricularis of the pelvic bone.

This work presents an automated data-mining model for age-at-death estimation based on 3D scans of the auricular surface of the pelvic bone. The study is based on a multi-population sample of 688 individuals (males and females) originating from one Asian and five European identified osteological collections. Our method requires no expert knowledge and achieves similar accuracy compared to traditional subjective methods. Apart from data acquisition, the whole procedure of pre-processing, feature extraction and age estimation is fully automated and implemented as a computer program. This program is a part of a freely available web-based software tool called CoxAGE3D. This software tool is available at https://coxage3d.fit.cvut.cz/ Our age-at-death estimation method is suitable for use on individuals with known/unknown population affinity and provides moderate correlation between the estimated age and actual age (Pearson's correlation coefficient is 0.56), and a mean absolute error of 12.4 years.

Protocol matters: A need for standardized procedure in cementochronology.

Cementochronology has long been associated in the literature with a high correlation between chronological and estimated age, and low differences between the two ages. The excessive accuracy was rather suspicious, and the method did not even appear in common forensic practice. An important step towards more widespread use of the method is the need to standardize work procedures, including indexes for recording the quality of cementum, preparation of thin sections and the age calculation. In our study, we used the standardized protocol for the preparation of thin sections in a set of Czech modern teeth of known age and sex. In the initial phase, 11.5% of the teeth were discarded due to severe caries in the medial part of the root. In a set of single extractions (55 teeth from 55 individuals), we focused on the detailed results of the age estimation, using precision and accuracy indicators. We also used different dental development data to calculate age, given inconsistencies in the use of eruption / mineralization. In a set of multiple extractions (68 teeth from 22 individuals), intra-individual variability was examined. The result of the application of the standardized protocol is an estimate of age with an absolute inaccuracy of -1.7 years and a relative inaccuracy of 5.4%. Calculation of precision and accuracy in the set of single extractions, however, showed the method's limitations: the imprecision measuring the variability of cementum increments counts increased with chronological age, as did the inaccuracy. The use of different dental development data did not significantly increase the accuracy of the age estimation results. Intra-individual variability remains poorly understood - in the set of multiple extractions the differences within one individual ranged between 0.9 and 10.8 years.