Three‐dimensional (3D) geometric morphometric analysis of human premolars to assess sexual dimorphism and biological ancestry in Australian populations

Yong, Robin; Ranjitkar, Sarbin; Lekkas, Dimitra; Halazonetis, Demetrios J.; Evans, Alistair R.; Brook, Alan; Townsend, Grant

doi:10.1002/ajpa.23438

Cited by 28 publications

(41 citation statements)

References 69 publications

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“…Since g i , g j are conformal, we have µ g i = µ g j = 0. Now, by the composition formula, we have (10) which implies that…”

Section: Composition For Obtaining the Landmark-matching Teichmüller mentioning

confidence: 99%

“…The detailed procedure for the tooth data acquisition and the landmark protocol were described in [10]. The dental casts of the subjects were scanned using a 3D scanner at the resolution of 80-µm point distance.…”

Section: Data Acquisition and Pre-processingmentioning

confidence: 99%

“…More specifcally, we consider the area-based classification [32,33] (note that the method in [32,33] was originally volume-based for genus-0 surfaces, and so its analogue for simply-connected open surfaces is area-based) and the Procrustes-based classification [10]. Table 1 summarizes the classification results obtained by the two previous methods and our proposed method.…”

Section: The Classification Accuracymentioning

confidence: 99%

“…Overall Accuracy (Our Method) Ancestry 67.14% 91.43% 98.57% Gender 51.43% 68.57% 97.14% Table 1: Classification accuracy for all the 140 upper second premolars with respect to ancestry and gender obtained by the area-based method [32,33], the Procrustes-based method [10] and our method. , and the overall accuracy is evaluated over all the 140 subjects.…”

Section: Classification Criterionmentioning

confidence: 99%

“…Traditional morphometric methods have been extensively used for the study of the human tooth variation in terms of tooth size [3], tooth weight [4] etc.. To have a better understanding of the tooth shape variation, it is more desirable to consider landmark-based geometric morphometrics, which compares teeth based on prescribed anatomical landmarks such as their cusps and pits. Earlier methods in landmark-based geometric morphometrics such as the Procrustes superimposition [5] and thin plate spline (TPS) transformation [6] have been applied for studying the dental variation of different populations [7,8,9,10]. However, a well-known limitation of these mapping methods is that in general neither the entire tooth shapes nor the landmarks can be exactly matched.…”

Section: Introductionmentioning

confidence: 99%

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Tooth morphometry using quasi-conformal theory

Choi

Chan

Yong

et al. 2020

Pattern Recognition

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Shape analysis is important in anthropology, bioarchaeology and forensic science for interpreting useful information from human remains. In particular, teeth are morphologically stable and hence well-suited for shape analysis. In this work, we propose a framework for tooth morphometry using quasi-conformal theory. Landmark-matching Teichmüller maps are used for establishing a 1-1 correspondence between tooth surfaces with prescribed anatomical landmarks. Then, a quasi-conformal statistical shape analysis model based on the Teichmüller mapping results is proposed for building a tooth classification scheme. We deploy our framework on a dataset of human premolars to analyze the tooth shape variation among genders and ancestries.Experimental results show that our method achieves much higher classification accuracy with respect to both gender and ancestry when compared to the existing methods. Furthermore, our model reveals the underlying tooth shape difference between different genders and ancestries in terms of the local * Corresponding author.

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“…Since g i , g j are conformal, we have µ g i = µ g j = 0. Now, by the composition formula, we have (10) which implies that…”

Section: Composition For Obtaining the Landmark-matching Teichmüller mentioning

confidence: 99%

Section: Data Acquisition and Pre-processingmentioning

confidence: 99%

Section: The Classification Accuracymentioning

confidence: 99%

Section: Classification Criterionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Tooth morphometry using quasi-conformal theory

Choi

Chan

Yong

et al. 2020

Pattern Recognition

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Sexual dimorphism of dental tissues in modern human mandibular molars

Sorenti

Martinón‐Torres

Martín‐Francés

et al. 2019

American J Phys Anthropol

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Objectives: Previous studies have revealed that human permanent dental tissue proportions differ significantly between males and females, with females having relatively thicker enamel relative to overall crown area than males. The aims of this study are to investigate sexual dimorphism in permanent mandibular molars and to determine whether such differences can be used to estimate sex in modern humans reliably. Materials and Methods:The permanent mandibular molars used in this study (n = 51) originate from 36 individuals of known sex from a Spanish anthropological collection. Eight variables were assessed from two-dimensional (2D) mesial planes of section obtained from microtomographic scans. Binary stepwise logistic regression was then applied to the data.Results: Male molars possess significantly greater quantities of dentine than females, both absolutely and proportionally. Females differed significantly from males by having greater relative enamel thickness. Logistic regression identified the proportion of dentine (relative dentine area [RDA]) as the most important sex discriminator, which can be used to correctly classify specimens with an overall accuracy rate of 74.36%.Discussion: These results confirm that sexual dimorphism in mandibular molar size is a result of males having a greater amount of dentine, both absolutely and proportionally. The findings suggest that 2D measurements of RDA may be useful for sex determination, although further research is required to test the reliability of these predictive techniques across different populations.K E Y W O R D S dental anthropology, dental tissue proportions, enamel thickness, microtomography, molars

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

Viciano

Tanga

D’Anastasio

et al. 2020

American J Phys Anthropol

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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.

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Three‐dimensional (3D) geometric morphometric analysis of human premolars to assess sexual dimorphism and biological ancestry in Australian populations

Cited by 28 publications

References 69 publications

Tooth morphometry using quasi-conformal theory

Tooth morphometry using quasi-conformal theory

Sexual dimorphism of dental tissues in modern human mandibular molars

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

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