Changes in human mandibular shape during the Terminal Pleistocene-Holocene Levant

Pokhojaev, Ariel; Avni, Hadas; Tunis, Tatiana Sella; Sarig, Rachel; May, Hila

doi:10.1038/s41598-019-45279-9

Cited by 18 publications

(17 citation statements)

References 61 publications

(68 reference statements)

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“…The first notable result of this analysis is that the x projection of the mandible image data is the most important for classification among the x, y, and z projections. This result is likely attributed to the fact that the area of the x projection is the largest and the results of Score-CAM, which focuses on the lateral view of the mandible is consistent with the previous studies in which the landmarks visible from the lateral view of the mandible are important in detecting sexual dimorphism [61][62][63] and inter-period variation [64]. Moreover, the analysis through a closer look at the x projection shows that the anatomically distinguishable projections of bone, i.e., the angular, condylar, and coronoid processes, are highlighted.…”

Section: Resultssupporting

confidence: 90%

A method for morphological feature extraction based on variational auto-encoder : an application to mandible shape

Tsutsumi

Saito

Koyabu

et al. 2022

Preprint

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Shape analysis of biological data is crucial for investigating the morphological variations during development or evolution. However, conventional approaches for quantifying shapes are difficult as exemplified by the ambiguity in the landmark-based method in which anatomically prominent “landmarks” are manually annotated. In this study, a morphological regulated variational autoencoder (Morpho-VAE) is proposed that conducts image-based shape analysis using imaging processing through a deep-learning framework, thereby removing the need for defining landmarks. The proposed architecture comprises a VAE combined with a classifier module. This integration of unsupervised and supervised learning models (i.e., VAE and classifier modules) is designed to reduce dimensionality by focusing on the morphological features in which the differences between data with different labels are best distinguished. The proposed method is applied to the image dataset of the primate mandible to extract morphological features, which allow us to distinguish different families in a low dimensional latent space. Furthermore, the visualization analysis of decision-making of Morpho-VAE clarifies the area of the mandibular joint that is important for family-level classification. The generative nature of the proposed model is also demonstrated to complement a missing image segment based on the remaining structure. Therefore, the proposed method, which flexibly performs landmark-free feature extraction from complete and incomplete image data is a promising tool for analyzing morphological datasets in biology.AUTHOR SUMMARYShape is the most intuitive visual characteristic; however, shape is generally difficult to measure using a small number of variables. Specifically, for biological data, shape is sometimes highly diverse as it has been acquired through a long evolutionary process, adaptation to environmental factors, etc., which limits the straightforward approach to shape measurement. Therefore, a systematic method for quantifying such a variety of shapes using a low-dimensional quantity is needed. To this end, we propose a novel method that extracts low-dimensional features to describe shapes from image data using machine learning. The proposed method is applied to the primate mandible image data to extract morphological features that reflect the characteristics of the groups to which the organisms belong and then those features are visualized. This method also reconstructs a missing image segment from an incomplete image based on the remaining structure. To summarize, this method is applicable to the shape analysis of various organisms and is a useful tool for analyzing a wide variety of image data, even those with a missing segment.

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Section: Resultssupporting

confidence: 90%

A method for morphological feature extraction based on variational auto-encoder : an application to mandible shape

Tsutsumi

Saito

Koyabu

et al. 2022

Preprint

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“…It is indeed remarkable that every third individual will present with some form of dental anomaly, a rate not seen in any other taxa. The human masticatory system has undergone a rapid and considerable reduction in size and orientation as a result of evolutionary changes [ 10 , 11 ], which are still ongoing [ 27 , 28 ]. This continuous pressure on the masticatory system to adapt to changing demands is likely related to the frequency in the occurrence of dental anomalies in humans.…”

Section: Discussionmentioning

confidence: 99%

Dental Anomalies’ Characteristics

et al. 2021

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The aim of this study was to characterize dental anomalies. The pretreatment records (photographs and radiographs) of 2897 patients (41.4% males and 58.6% females) were utilized to detect dental anomalies. The dental anomalies studied were related to number, size and shape, position, and eruption. A Chi-square test was carried out to detect associations between dental anomalies, jaw, and sex. A total of 1041 (36%) of the subjects manifested at least one dental anomaly. The prevalence of all dental anomalies was jaw-dependent and greater in the maxilla, except for submerged and transmigrated teeth. The most frequently missing teeth were the maxillary lateral incisor (62.3%) and the mandibular second premolars (60.6%). The most frequent supernumerary teeth were the incisors in the maxilla (97%) and the first premolars in the mandible (43%). Dental anomalies are more frequent in the maxilla and mainly involve the anterior teeth; in the mandible, however, it is the posterior teeth. These differences can be attributed to the evolutionary history of the jaws and their diverse development patterns.

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“…However, it should be noted that the anatomical changes in rodent models are subtle and can hardly be localized by linear measurements. Our analyses were therefore based on geometrics morphometrics being widely recognized as robust and sophisticated diagnostic tools for determining shape changes, particularly in anthropology 15‐17 . This type of analysis has also been used in dentistry, including orthodontics 18‐20 and craniofacial surgery 21 .…”

Section: Discussionmentioning

confidence: 99%

“…Our analyses were therefore based on geometrics morphometrics being widely recognized as robust and sophisticated diagnostic tools for determining shape changes, particularly in anthropology. [15][16][17] This type of analysis has also been used in dentistry, including orthodontics [18][19][20] and craniofacial surgery. 21 In addition, we have recently proposed the use of geometrics morphometrics to characterize skull deformation in sclerostin knockout mice.…”

Section: Discussionmentioning

confidence: 99%

Caspase inhibitor attenuates the shape changes in the alveolar ridge following tooth extraction: A pilot study in rats

Schwarze

Strauß

Gruber

2020

J of Periodontal Research

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Objective The aim of the study was to determine whether the inhibition of apoptosis via pan‐caspase inhibitors can attenuate the changes in the alveolar ridge upon tooth extraction. Background Cells undergoing apoptosis might play a central role in the onset of alveolar bone resorption and the ensuing bone atrophy following tooth extraction. Caspases are proteases that regulate apoptotic cell death. It is, therefore, reasonable to hypothesize that blocking apoptosis with pan‐caspase inhibitors attenuates the changes in the alveolar ridge following tooth extraction. Methods In 16 inbred rats, the mandibular first (M1) and second (M2) molars of one side were extracted. Following random allocation, the rats received either a cell‐permeable pan‐caspase inhibitor or diluent. After a healing period of 10 days, changes in shape and height of the alveolar ridge were examined using geometric morphometrics and linear measurements based on micro‐computed tomography. Results Geometric morphometric analysis revealed that the pan‐caspase inhibitor prevented major shape changes of the alveolar ridge following M1 tooth extraction (P < .05). Furthermore, linear measurements confirmed that the pan‐caspase inhibitor significantly prevented the atrophy of the alveolar ridge height following M1 tooth extraction compared to the diluent controls (−0.53 mm vs −0.24 mm; P = .012). M2 tooth extraction caused no shape changes of the alveolar ridge, and thus, the pan‐caspase inhibitor group did not differ from the control group (−0.14 mm vs −0.05 mm; P = .931). Conclusions These findings suggest that the inhibition of apoptosis may attenuate shape changes of the alveolar ridge following M1 tooth extraction in rodents.

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Changes in human mandibular shape during the Terminal Pleistocene-Holocene Levant

Cited by 18 publications

References 61 publications

A method for morphological feature extraction based on variational auto-encoder : an application to mandible shape

A method for morphological feature extraction based on variational auto-encoder : an application to mandible shape

Dental Anomalies’ Characteristics

Caspase inhibitor attenuates the shape changes in the alveolar ridge following tooth extraction: A pilot study in rats

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