Odontometric sex estimation on three populations of the Iron Age from Abruzzo region (central-southern Italy)

Are deciduous upper molars and lower canines useful for sex estimation?

OBJECTIVE

This paper investigates whether deciduous upper molars and lower canines have sexual dimorphic features, exploring these teeth' dimensions and the presence of Zuckerkandl's tubercle and Carabelli's cusp on the first and second upper molars.

DESIGN

We analyzed 64 pairs of dental plaster casts from 34 females and 30 males aged between 3 and 12 years. We measured the first and second deciduous upper molars and the lower deciduous canines (maximum mesiodistal and buccolingual length), and we registered the presence of the Zuckerkandl's tubercle and the Carabelli's cusp on the first and second upper molars, respectively.

RESULTS

Regarding the differentiation between sexes using Carabelli's cusp and Zuckerkandl's tubercle, the classification was not independent of Carabelli's cusp presence only for tooth 65 (p = 0.035). In all other teeth, whether for Carabelli's cusp or Zuckerkandl's tubercle, their presence was similar for both sexes. There were statistically significant differences between sexes (p < 0.05) for the buccolingual measurements of both upper second molars, the first right upper molar, and the right canine. The developed model allowed for a 64.1% accuracy in sex estimation.

CONCLUSIONS

The study suggests that while Carabelli's cusp and Zuckerkandl's tubercle in upper deciduous molars don't consistently differ between sexes, tooth size, particularly the buccolingual measurements of certain teeth, including upper deciduous molars and lower canines, may provide a more reliable criterion for sex estimation. The developed model depicted moderate accuracy, underscoring the need for a multifactorial approach when estimating sex from skeletal remains. It suggests that while dental features can contribute to sex estimation, they should be used in conjunction with other skeletal or molecular markers to improve accuracy.

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.

How teeth can be used to estimate sexual dimorphism? A scoping review

INTRODUCTION

Teeth are biological structures with a high degree of hardness, density, calcification, and capacity to adapt to extrinsic factors at physical, biological, and physiological levels. Subsequently, they resist for a longer period in deteriorating environmental conditions. With dental analysis, it is possible to acquire biographical data about a person. The aim of this scoping review was to identify publications using human teeth tissues to estimate sexual dimorphism.

METHODS

The scoping review was carried out in the following databases: Jstor, Scielo, Science Direct, PubMed, and Scopus, using ten search strategies in English and guaranteeing completeness and reproducibility of the phases stipulated in the PRISMA guide.

RESULTS

143 studies on sexual dimorphism based on dental tissue traits were included, of which 40.6% (n = 58) were done in Asia and 27.2% (n = 39) in America. 80% of the studies (equivalent to 114 articles) focused their observations and measurements on the dental crown; 4.2% in enamel, dentin, and pulp together; 3.5% in dental pulp; 2.1% in the entire tooth; 2.8% in enamel, root, and the enamel-cementum junction, and only 0.7% in dentin and pulp. In addition, 92.3% of the studies used metric methods, while only 4.9% and 2.8% used biochemical and non-metric method respectively.

CONCLUSION

For sexual dimorphism establishment, enamel has been the most analyzed dental tissue in permanent canines and molars mainly. Likewise, the most widely and accurately used methods for this purpose are the metrics, with the odontometry as the most implemented (intraoral or by using dental plaster models, digital scanning or software) with prediction percentages ranging from 51% to 95.9%. In contrast to biochemical methods, that can achieve the highest precision (up to 100%), the non-metric methods, to a less extent, reported prediction percentages of 58%.

Unbalanced sex-ratio in the Neolithic individuals from the Escoural Cave (Montemor-o-Novo, Portugal) revealed by peptide analysis

The sex profile estimation of pre-historic communities is often complicated by the commingled and scattered nature of skeletal assemblages. Demographic profiles are usually lacking and provide very truncated representations of these populations but proteomic analysis of sex-specific amelogenin peptides in tooth enamel brings new promise to these studies. The main objective was to obtain the sex profile of the human assemblage recovered from the Neolithic cave-necropolis of Escoural (Montemor-o-Novo, southern Portugal) through liquid chromatography-mass spectrometry. The secondary objective was to analyse sex-specific linear enamel hypoplasias (LEH), and to test the reliability of canine odontometric sex estimation. Sex estimation through peptide analysis was carried out in 36 left permanent canines which were macroscopically examined for the presence of LEH. The canine buccolingual diameter was used for odontometric sex estimation. The obtained sex ratio (0.5:1, M:F) is biased to female individuals, probably due to cultural factors since the natural sex ratio of the human population falls between 0.95:1 and 1.02:1 (M:F). A high frequency of LEH was observed, but with no significant sexual differences (p = 0.554). The mean LEH age of onset occurred at 3 years of age, with no significant differences between the sexes (p = 0.116), and was possibly related to the weaning process. Odontometric sex estimation revealed a correct classification of 80%, with a high number of males mistakenly attributed to females. This study is one of the largest samples subjected to peptide analysis, and thus demonstrates its usefulness on the research of commingled and scattered skeletal assemblages.

Stable Isotopes Unveil Dietary Trends in the Samnite and Peligni Communities of Opi Val Fondillo and Sulmona S. Lucia (V-VI Centuries BCE, Abruzzo, Central Italy)

The purpose of this study is to gain insights into the subsistence activities and nutrition of the Samnite and Peligni populations who lived in the Abruzzo region (Italy) during the Iron Age. The samples under investigation are from Opi Val Fondillo (AQ) and Sulmona S. Lucia (AQ), dating between the Vth and VIth centuries BCE. Carbon and nitrogen isotopes were utilized to characterize the diet of the inhabitants in this region. The study involved analyzing carbon and nitrogen stable isotopes in 84 available samples and comparing them with isotopic values from animals found in the nearby sites of Loreto Aprutino, Gabii, and La Sassa's Cave. The results of this study revealed statistically significant differences between sexes in δ15N values. Additionally, significant statistical variations were observed when comparing different populations.

Canine Crown Sexual Dimorphism in a Sample of the Modern Croatian Population

Sex assessment is a key part of forensic analysis to establish the identity of unknown deceased individuals. Previous studies have shown that canines are the most dimorphic teeth, but population-specific data are necessary for forensic methods. This study explores sex dimorphism in canine crown dimensions and morphology in a contemporary Croatian population. The material consisted of 302 dental casts (147 females, 155 males) of orthodontic patients and dental students (11-25 years). The distal accessory ridge (DAR) of the upper and lower canines was evaluated using the Arizona State University Dental Anthropology System. Mesiodistal (MD) and buccolingual (BL) crown dimensions were measured on 120 casts. Sex differences in MD and BL dimensions were significant (p < 0.05) for all the canines (upper and lower, left and right), while in DAR only for lower canines (p < 0.000001). When all variables were put into the model, backward stepwise discriminant function analysis isolated lower canine DAR and lower left canine MD as the two independent variables differentiating sex. Using these two variables, a discriminant function formula allowed for sex determination with an accuracy of 73.5%. This study shows that both canine crown morphology and dimensions are useful for sex determination, especially for lower canines. These methods can be applied to children, as lower canines erupt at about 9 years of age.

Accuracy comparison of tooth volume and mesiodistal diameter measurements for sex dimorphism based on cone-beam computed tomography: a study for the northern Chinese population

Sex estimation based on teeth could help to narrow the scope for individual identification. According to the different teeth morphology among both genders, we plan to establish a sex estimation method for the northern Chinese population through mesiodistal diameter and teeth volume measurements and compare the accuracy of the two methods. In this study, measurements were taken from cone-beam computed tomography images collected from 142 males and 140 females aged 21-59 years. The mesiodistal diameter and volume of the left canines and the first molars in both upper and lower jaws were measured and analyzed for suitable coefficients. We selected 80% samples as the training set to set up the logistic regression formulas and 20% as the test set to obtain accuracy. The accuracy of sex estimation by mesiodistal diameter can reach 87.50%, and the volume is up to 78.57%. The measurement of mesiodistal diameter is less time-consuming. This work established and tested a method to estimate sex for the northern Chinese population. Results showed that sex estimation based on the mesiodistal diameter of teeth has higher accuracy than the method based on teeth volume.

Automatic sex estimation using deep convolutional neural network based on orthopantomogram images

Sex estimation is very important in forensic applications as part of individual identification. Morphological sex estimation methods predominantly focus on anatomical measurements. Based on the close relationship between sex chromosome genes and facial characterization, craniofacial hard tissues morphology shows sex dimorphism. In order to establish a more labor-saving, rapid, and accurate reference for sex estimation, the study investigated a deep learning network-based artificial intelligence (AI) model using orthopantomograms (OPG) to estimate sex in northern Chinese subjects. In total, 10703 OPG images were divided into training (80%), validation (10%), and test sets (10%). At the same time, different age thresholds were selected to compare the accuracy differences between adults and minors. The accuracy of sex estimation using CNN (convolutional neural network) model was higher for adults (90.97%) compared with minors (82.64%). This work demonstrated that the proposed model trained with a large dataset could be used in automatic morphological sex-related identification with favorable performance and practical significance in forensic science for adults in northern China, while also providing a reference for minors to some extent.

What is the effect of preterm birth on permanent tooth crown dimensions? A systematic review and meta-analysis

BACKGROUND

The permanent tooth formation process may be disrupted in preterm infants with potential discrepancies in size and subsequent occlusal disturbances.

OBJECTIVE

To systematically analyse and quantitively synthesize the available evidence regarding the impact of preterm birth on permanent tooth crown dimensions.

SEARCH METHODS

Unrestricted searches in 6 databases and manual searching of the reference lists in relevant studies were performed up to March 2021 (Medline via PubMed, CENTRAL, Cochrane Database of Systematic Reviews, Scopus, Web of Science, ProQuest Dissertations and Theses Global).

SELECTION CRITERIA

Observational studies investigating permanent tooth crown dimensions in preterm and control full-term born individuals.

DATA COLLECTION AND ANALYSIS

Following study retrieval and selection, relevant data were extracted, and the Newcastle-Ottawa scale was used to assess the selection, comparability, and outcome domains. Exploratory synthesis and meta-regression were carried out using the random effects model.

RESULTS

Three studies were located from the initially retrieved records and the assessments with the Newcastle-Ottawa scale identified issues regarding the selection and comparability domains. Overall, the mesiodistal and the buccolingual dimensions of the permanent teeth in both dental arches tended to be smaller in children born prematurely than full term children. Subgroup analyses showed statistically significant differences for the extremely preterm to control group comparisons for the incisors and the first molars. Meta-regression showed a modificatory effect of gestational age and racial background but not of birth weight and gender on tooth size. The quality of available evidence was rated at best as moderate.

CONCLUSIONS

Premature birth could potentially be associated with reduced tooth-crown dimensions in some permanent teeth especially in children born extremely preterm. Although the results from these observational studies should be approached with caution until more information becomes available, the possible clinical implications in terms of diagnosis and treatment planning should be considered.

REGISTRATION

PROSPERO (CRD42020182243).

Adult sex estimation from the minimum supero-inferior femoral neck diameter in a contemporary osteological sample from Buenos Aires, Argentina

Sex estimation of adult skeletons is an important step in forensic analysis. Although the femur has been metrically studied for sex assessment around the world, very limited information is actually available on modern populations of Argentina. In this paper, the estimation of sex based on the metric evaluation of the supero-inferior femoral neck diameter (SID) in a reference osteological collection from the contemporary Chacarita Cemetery of Buenos Aires City (Argentina), is evaluated. Protocols generated using SID in other three reference skeletal samples are also tested on this collection. One hundred and sixty-four individuals of both sexes and between 24 and 96 years old are analyzed. Inter and intra observer errors suggest that the replicability of the procedure is adequate. The sectioning point calculated from the direct measurements is 30.86 mm and results show a high degree of dimorphism. The proportions of correct sex discrimination and the likelihoods of correct allocation obtained with the direct measurements, along with the results of a discriminant function, a binary logistic regression and a Bayesian approach, are all higher than 0.85 (0.85-0.93 for females, 0.88-0.91 for males). When the formulae from other samples are used in the Chacarita Collection, the percentages of correct estimations range between 72.41% and 81.03% for females and between 80.46% and 88.50% for males, while the likelihoods are between 0.73 and 0.81 for females and between 0.79 and 0.82 for males. As the values for the estimations obtained using the statistical procedures generated in the present research are higher than those available for other collections, the method is more adequate to use in the analysis of contemporary skeletal remains from Buenos Aires and surrounding areas. The trends identified highlight the importance of population-specific metric methodologies in forensic contexts and deserve future testing in contemporary samples from neighbouring regions.

Dimorphism in dental tissues: Sex differences in archaeological individuals for multiple tooth types

OBJECTIVES

Dimorphism in the dentition has been observed in human populations worldwide. However, research has largely focused on traditional linear crown measurements. As imaging systems, such as micro-computed tomography (micro-CT), become increasingly more accessible, new dental measurements such as dental tissue size and proportions can be obtained. This research investigates the variation of dental tissues and proportions by sex in archaeological samples.

MATERIALS AND METHODS

Upper and lower first incisor to second premolar tooth rows were obtained from 30 individuals (n = 300), from 3 archaeological samples. The teeth were micro-CT scanned and surface area and volumetric measurements were obtained from the surface meshes extracted. Dental wear was also recorded and differences between sexes determined.

RESULTS

Enamel and crown measurements were found to be larger in females. Conversely, dentine and root measurements were larger in males.

DISCUSSION

The findings support the potential use of dental tissues to estimate sex of individuals from archaeological samples, while also indicating that individuals aged using current dental aging methods may be underaged or overaged due to sex differences in enamel thickness.

Sex estimation by odontometrics of nonadult human remains from a contemporary Italian sample

OBJECTIVES

The objective was to develop an odontometric technique for sex estimation based on dental measurements from adult individuals, and to evaluate its applicability and reliability for diagnosis of sex of nonadult skeletal remains.

MATERIALS AND METHODS

This study was conducted on the permanent dentition of 132 individuals (70 males, 62 females) from the identified human skeletal collection of the Certosa Cemetery (Bologna, Italy) of the University of Bologna. Binary logistic regression equations were developed based on dental measurements of the permanent teeth of the adult individuals, and these equations were subsequently applied to the permanent dentition of nonadult individuals to estimate their sex.

RESULTS

These data show that the canine teeth of both the maxilla and mandible are the most sexually dimorphic teeth in adults, followed by the mandibular second molar, maxillary and mandibular second and first premolars, and mandibular first molar. These data provided correct assignment of sex in 80.4-94.9% of cases, which depended on the measurements used. Of the 26 nonadult individuals of the experimental sample, sex diagnosis was possible for 22, which represented an applicability rate of 84.6% of the individuals. Comparing the sex of these 22 nonadult individuals estimated by odontometrics with the known biological sex, correct assignment was obtained in 90.9% of cases.

CONCLUSION

As a method of sex estimation, odontometric analysis of permanent dentition can be used successfully for nonadult human skeletal remains in both forensic and archeological contexts.

Sex estimation of the humerus: A geometric morphometric analysis in an adult sample

Sex estimation is the keystone for positive identification when an unidentified human body is recovered in forensic contexts. However, in complex death scenes such as mass disasters, the remains are often fleshed, mutilated, burned, and/or commingled. In situations such as these where it is not possible to analyze pelvis and/or cranium data, traditional metric and qualitative morphological methods on postcranial bones can yield unsatisfactory results. In such cases, geometric morphometric techniques offer an alternative to the analysis of both shape and size components of morphological variation that can be of great utility for sex estimation in forensic investigations. The study population consisted of 72 well-preserved adult humeri (40 males and 32 females; mean age of 62 years) that were photographed in standardized positions with landmarks located in four two-dimensional views of the humerus (anterior surface of the proximal epiphysis, and anterior, posterior and inferior surface of distal epiphysis). Principal components analysis, canonical variates analysis and discriminant analysis were applied. The data indicated that males and females were classified with low levels of accuracy (54.95-77.92% for males; 56.87-71.78% for females) based on shape variables. However, when the shape variable was combined with the centroid size, the levels of accuracy increased (81.86-94.92% for males; 84.08-94.88% for females). To obtain larger differences between males and females, it is necessary the combination of centroid size with shape variables; the shape of the humerus is insufficient to discriminate sex with accuracy.

Correlation coefficients for predicting canine diameters from premolar and molar sizes

Background/purpose

The permanent canine is the most widely used tooth for sex estimation because it is the tooth with the highest degree of sexual dimorphism; however, there are several factors that can limit the analysis (e.g., pathologies, postmortem loss). The aim of this work was to analyse the correlation between the dimensions of the canines and those of the premolars and molars, and evaluate the correspondence of real and predicted canine dimensions by applying the equations developed.

Materials and methods

The sample was composed of digital models of 80 adult individuals from Temuco, Chile. The buccolingual and mesiodistal diameters of the canine, premolar and molar dental crowns were measured and Pearson's linear regression analysis was performed in order to determine the correlation between the diameters. The equations obtained from the reference subsample were applied to a validation subsample to predict canine dimensions from the dimensions of the postcanine teeth.

Results

Four regression equations were obtained, all for prediction of the size of the lower canines, whose correlation coefficient ranged from 0.701 to 0.738. The regression equations developed with the reference sample were tested on the validation sample using a Student's t-test for paired samples and the intraclass correlation coefficient. The differences between actual dental size and that predicted by the equations were not significantly different, and concordance analysis showed a moderate degree (0.485–0.585).

Conclusion

There is a limited correlation of canine dimensions with respect to premolars and molars. The correspondence between the actual and predicted canines dimensions is moderate.

Hemifacial microsomia (oculo-auriculo-vertebral spectrum) in an individual from the Teramo Sant'Anna archaeological site (7th-12th centuries of the Common Era, Italy)

BACKGROUND

This study is based in an analysis of the skeletal remains of an adult male from the Teramo Sant'Anna archaeological site (7th-12th centuries of the Common Era, Teramo, Italy).

RESULTS AND DISCUSSION

The individual shows distinct abnormalities that principally involve asymmetric hypoplasia and dysmorphogenesis of the facial skeleton. The combination of these findings and the absence of abnormalities of the spine strongly suggest diagnosis of the congenital malformation known as hemifacial microsomia. This very heterogeneous syndrome affects primarily aural, ocular, oral and mandibular development. Despite the lack of clinical information and the absence of soft tissue, it was possible to perform a differential diagnosis for this palaeopathological case. Mastication was probably altered considering that the mandible is extremely asymmetric and lacks true condyles. The temporomandibular joints are present, but the right one is hypoplastic and abnormal in shape. There is evidence of bilateral dislocation, and the facial muscles are hypertrophic.

CONCLUSIONS

This case represents an important contribution to the palaeopathological literature because this is an uncommon condition that has not been widely documented in ancient skeletal remains.

A novel method for sex estimation using 3D computed tomography models of tooth roots: A volumetric analysis

Advances in technologies such as computed tomography (CT) scanning have allowed for further examination of dental sexual dimorphism in modern and archaeological populations.

Dental occlusion analysis in the Mesolithic-Neolithic Age, Bronze Age, and Roman to Medieval times in Serbia: Tooth size comparison in skeletal samples

OBJECTIVE

Anthropological studies have reported that tooth size decreases in the context of diet changes. Some investigations have found a reverse trend in tooth size from the prehistoric to the modern times. The aims of this study were to analyze tooth size in skeletal samples from Mesolithic-Neolithic Age, Bronze Age, and Roman to Medieval times to determine sex differences and establish a temporal trend in tooth size in the aforementioned periods.

DESIGN

Well-preserved permanent teeth were included in the investigation. The mesiodistal (MD) diameter of all teeth and buccolingual (BL) diameter of the molars were measured. Effects of sex and site were tested by one-way ANOVA, and the combined effect of these factors was analyzed by UNIANOVA.

RESULTS

Sexual dimorphism was present in the BL diameters of all molars and MD diameters of the upper first and the lower third molar. The lower canine was the most dimorphic tooth in the anterior region. The MD diameter of most teeth showed no significant difference between the groups, (sample from: Mesolithic-Neolithic Age-group 1; Bronze Age-group 2; Roman times-group 3; Medieval times-group 4), whereas the BL diameters of the upper second and the lower first molar were the largest in the first group. Multiple comparisons revealed a decrease in the BL diameter of the upper second and the lower first molar from the first to the later groups. Lower canine MD diameter exhibited an increase in the fourth group compared to the second group.

CONCLUSION

On the basis of the MD diameter, a temporal trend could not be observed for most of the teeth. The lower canine exhibited an increase in the MD diameter from the prehistoric to the Medieval times. Changes of BL diameter were more homogeneous, suggesting that the temporal trend of molar size decreased from the Mesolithic-Neolithic to Medieval times in Serbia.