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Buck LT, Menéndez LP, De Groote I, Hassett BR, Matsumura H, Stock JT. Factors influencing cranial variation between prehistoric Japanese forager populations. ARCHAEOLOGICAL AND ANTHROPOLOGICAL SCIENCES 2023; 16:3. [PMID: 38098511 PMCID: PMC10716076 DOI: 10.1007/s12520-023-01901-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Accepted: 11/09/2023] [Indexed: 12/17/2023]
Abstract
Understanding the factors shaping human crania has long been a goal of biological anthropology, and climate, diet, and population history are three of the most well-established influences. The effects of these factors are, however, rarely compared within a single, variable population, limiting interpretations of their relative contribution to craniofacial form. Jomon prehistoric foragers inhabited Japan throughout its climatic and ecological range and developed correspondingly varied modes of subsistence. We have previously demonstrated that a large sample of Jomon crania showed no clear climatic pattern; here, we examine variation in Jomon crania in more detail to determine if dietary factors and/or population history influence human intrapopulation variation at this scale. Based on well-established archaeological differences, we divide the Jomon into dietary groups and use geometric morphometric methods to analyse relationships between cranial shape, diet, and population history. We find evidence for diet-related influences on the shape of the neurocranium, particularly in the temporalis region. These shape differences may be interpreted in the context of regional variation in the biomechanical requirements of different diets. More experimental biomechanical and nutritional evidence is needed, however, to move suggested links between dietary content and cranial shape from plausible to well-supported. In contrast with the global scale of human variation, where neutral processes are the strongest influence on cranial shape, we find no pattern of population history amongst individuals from these Jomon sites. The determinants of cranial morphology are complex and the effect of diet is likely mediated by factors including sex, social factors, and chronology. Our results underline the subtlety of the effects of dietary variation beyond the forager/farmer dichotomy on cranial morphology and contribute to our understanding of the complexity of selective pressures shaping human phenotypes on different geographic scales. Supplementary Information The online version contains supplementary material available at 10.1007/s12520-023-01901-6.
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Affiliation(s)
- L. T. Buck
- Research Centre for Evolutionary Anthropology and Palaeoecology, Liverpool John Moores University, Byrom Street, Liverpool, L3 3AF UK
| | - L. P. Menéndez
- Department of Anthropology of the Americas, University of Bonn, Oxfordstrasse 15, 53111 Bonn, Germany
- Department of Evolutionary Biology, University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria
| | - I. De Groote
- Department of Archaeology, Ghent University, Sint-Pietersnieuwstraat 35, 9000 Ghent, Belgium
| | - B. R. Hassett
- University of Central Lancashire, Fylde Rd, Preston, PR1 2HE Lancashire UK
- Natural History Museum London, Cromwell Road, London, SW7 5BD UK
| | - H. Matsumura
- School of Health Sciences, Sapporo Medical University, S1W17, Sapporo, 0608556 Japan
| | - J. T. Stock
- Department of Anthropology, Western University, London, ON N6A 3K7 Canada
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Panagiotopoulou O, Robinson D, Iriarte-Diaz J, Ackland D, Taylor AB, Ross CF. Dynamic finite element modelling of the macaque mandible during a complete mastication gape cycle. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220549. [PMID: 37839457 PMCID: PMC10577025 DOI: 10.1098/rstb.2022.0549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Accepted: 09/14/2023] [Indexed: 10/17/2023] Open
Abstract
Three-dimensional finite element models (FEMs) are powerful tools for studying the mechanical behaviour of the feeding system. Using validated, static FEMs we have previously shown that in rhesus macaques the largest food-related differences in strain magnitudes during unilateral postcanine chewing extend from the lingual symphysis to the endocondylar ridge of the balancing-side ramus. However, static FEMs only model a single time point during the gape cycle and probably do not fully capture the mechanical behaviour of the jaw during mastication. Bone strain patterns and moments applied to the mandible are known to vary during the gape cycle owing to variation in the activation peaks of the jaw-elevator muscles, suggesting that dynamic models are superior to static ones in studying feeding biomechanics. To test this hypothesis, we built dynamic FEMs of a complete gape cycle using muscle force data from in vivo experiments to elucidate the impact of relative timing of muscle force on mandible biomechanics. Results show that loading and strain regimes vary across the chewing cycle in subtly different ways for different foods, something which was not apparent in static FEMs. These results indicate that dynamic three-dimensional FEMs are more informative than static three-dimensional FEMs in capturing the mechanical behaviour of the jaw during feeding by reflecting the asymmetry in jaw-adductor muscle activations during a gape cycle. This article is part of the theme issue 'Food processing and nutritional assimilation in animals'.
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Affiliation(s)
- Olga Panagiotopoulou
- Monash Biomedicine Discovery Institute, Department of Anatomy and Developmental Biology, Monash University, Melbourne, Victoria 3800, Australia
| | - Dale Robinson
- Department of Biomedical Engineering, University of Melbourne, Melbourne, Victoria 3053, Australia
| | - Jose Iriarte-Diaz
- Department of Biology, University of the South, Sewanee, TN 37383, USA
| | - David Ackland
- Department of Biomedical Engineering, University of Melbourne, Melbourne, Victoria 3053, Australia
| | - Andrea B. Taylor
- Department of Foundational Biomedical Sciences, Touro University California, Vallejo, CA 94592, USA
| | - Callum F. Ross
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL 60637, USA
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Semple BD, Panagiotopoulou O. Cranial Bone Changes Induced by Mild Traumatic Brain Injuries: A Neglected Player in Concussion Outcomes? Neurotrauma Rep 2023; 4:396-403. [PMID: 37350792 PMCID: PMC10282977 DOI: 10.1089/neur.2023.0025] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/24/2023] Open
Abstract
Mild traumatic brain injuries (TBIs), particularly when repetitive in nature, are increasingly recognized to have a range of significant negative implications for brain health. Much of the ongoing research in the field is focused on the neurological consequences of these injuries and the relationship between TBIs and long-term neurodegenerative conditions such as chronic traumatic encephalopathy and Alzheimer's disease. However, our understanding of the complex relationship between applied mechanical force at impact, brain pathophysiology, and neurological function remains incomplete. Past research has shown that mild TBIs, even below the threshold that results in cranial fracture, induce changes in cranial bone structure and morphology. These structural and physiological changes likely have implications for the transmission of mechanical force into the underlying brain parenchyma. Here, we review this evidence in the context of the current understanding of bone mechanosensitivity and the consequences of TBIs or concussions. We postulate that heterogeneity of the calvarium, including differing bone thickness attributable to past impacts, age, or individual variability, may be a modulator of outcomes after subsequent TBIs. We advocate for greater consideration of cranial responses to TBI in both experimental and computer modeling of impact biomechanics, and raise the hypothesis that calvarial bone thickness represents a novel biomarker of brain injury vulnerability post-TBI.
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Affiliation(s)
- Bridgette D. Semple
- Department of Neuroscience, Monash University, Prahran, Victoria, Australia
- Department of Neurology, Alfred Health, Prahran, Victoria, Australia
- Department of Medicine (Royal Melbourne Hospital), University of Melbourne, Parkville, Victoria, Australia
| | - Olga Panagiotopoulou
- Monash Biomedicine Discovery Institute, Department of Anatomy and Developmental Biology, Monash University, Clayton, Victoria, Australia
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Decaup PH, Couture C, Garot E. Is the distribution of cortical bone in the mandibular corpus and symphysis linked to loading environment in modern humans? A systematic review. Arch Oral Biol 2023; 152:105718. [PMID: 37182318 DOI: 10.1016/j.archoralbio.2023.105718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 04/25/2023] [Accepted: 05/06/2023] [Indexed: 05/16/2023]
Abstract
OBJECTIVE The human mandible is a unique bone with specific external and internal morphological characteristics, influenced by a complex and challenging loading environment. Mandibular cortical thickness distribution in cross-sections is reported to be related to facial divergence patterns, cultural and dietary habits and more generally, specific loading environment. This review hypothesises that a process of environmental mechanical sensitivity is involved in the distribution of cortical bone in the mandibular corpus and symphysis in modern humans, and that loading regimes can influence this distribution pattern. Based on a review of the recent literature, this study aims to answer the following question: "Is the distribution of cortical bone in the mandibular corpus and symphysis linked to the loading environment in modern humans?" DESIGN A systematic review was undertaken using the PubMed/Medline, Scopus and Cochrane Library databases for publications from 1984 to 2022 investigating the relationship between cortical bone distribution in the mandibular corpus and the loading environment. A subgroup meta-analysis was performed to determine the overall effect of facial divergence on cortical thickness. RESULTS From a total of 2791 studies, 20 fulfilled the inclusion criteria. The meta-analyses were performed in eight studies using a randomised model, finding a significant overall effect of facial divergence on cortical thickness in posterior areas of the mandible (p < 0.01). CONCLUSIONS Within the limitations of this review, specific loading regimes and their consequent variables (diet, culture, facial divergence) were linked to cortical thickness distribution. Sex was found to be unrelated to cortical thickness pattern.
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Affiliation(s)
- Pierre-Hadrien Decaup
- Université de Bordeaux, PACEA, UMR 5199, Pessac, France; Université de Bordeaux, UFR des Sciences Odontologiques, Bordeaux, France.
| | | | - Elsa Garot
- Université de Bordeaux, PACEA, UMR 5199, Pessac, France; Université de Bordeaux, UFR des Sciences Odontologiques, Bordeaux, France
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Byron C, Reed D, Iriarte-Diaz J, Wang Q, Strait D, Laird MF, Ross CF. Sagittal suture strain in capuchin monkeys (Sapajus and Cebus) during feeding. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2023; 180:633-654. [PMID: 36790169 DOI: 10.1002/ajpa.24701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 12/13/2022] [Accepted: 01/16/2023] [Indexed: 05/26/2023]
Abstract
OBJECTIVES Morphological variation in cranial sutures is used to infer aspects of primate feeding behavior, including diet, but strain regimes across sutures are not well documented. Our aim is to test hypotheses about sagittal suture morphology, strain regime, feeding behavior, and muscle activity relationships in robust Sapajus and gracile Cebus capuchin primates. MATERIALS AND METHODS Morphometrics of sinuosity in three regions of the sagittal suture were compared among museum specimens of Sapajus and Cebus, as well as in robust and gracile lab specimens. In vivo strains and bilateral electromyographic (EMG) activity were recorded from these regions in the temporalis muscles of capuchin primates while they fed on mechanically-varying foods. RESULTS Sapajus and the anterior suture region exhibited greater sinuosity than Cebus and posterior regions. In vivo data reveal minor differences in strain regime between robust and gracile phenotypes but show higher strain magnitudes in the middle suture region and higher tensile strains anteriorly. After gage location, feeding behavior has the most consistent and strongest impact on strain regime in the sagittal suture. Strain in the anterior suture has a high tension to compression ratio compared to the posterior region, especially during forceful biting in the robust Sapajus-like individual. DISCUSSION Sagittal suture complexity in robust capuchins likely reflects feeding behaviors associated with mechanically challenging foods. Sutural strain regimes in other anthropoid primates may also be affected by activity in feeding muscles.
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Affiliation(s)
- Craig Byron
- Department of Biology, Mercer University, Macon, Georgia, USA
| | - David Reed
- Department of Oral Biology, University of Illinois, Chicago, Illinois, USA
| | - Jose Iriarte-Diaz
- Department of Biology, University of the South, Sewanee, Tennessee, USA
| | - Qian Wang
- Department of Biomedical Sciences, Texas A&M University College of Dentistry, Dallas, Texas, USA
| | - David Strait
- Department of Anthropology, Washington University in St. Louis, St. Louis, Missouri, USA
- Palaeo-Research Institute, University of Johannesburg, Johannesburg, South Africa
| | - Myra F Laird
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Callum F Ross
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, Illinois, USA
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Sharp AC, Dutel H, Watson PJ, Gröning F, Crumpton N, Fagan MJ, Evans SE. Assessment of the mechanical role of cranial sutures in the mammalian skull: Computational biomechanical modelling of the rat skull. J Morphol 2023; 284:e21555. [PMID: 36630615 PMCID: PMC10107956 DOI: 10.1002/jmor.21555] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 01/03/2023] [Accepted: 01/05/2023] [Indexed: 01/13/2023]
Abstract
Cranial sutures are fibrocellular joints between the skull bones that are progressively replaced with bone throughout ontogeny, facilitating growth and cranial shape change. This transition from soft tissue to bone is reflected in the biomechanical properties of the craniofacial complex. However, the mechanical significance of cranial sutures has only been explored at a few localised areas within the mammalian skull, and as such our understanding of suture function in overall skull biomechanics is still limited. Here, we sought to determine how the overall strain environment is affected by the complex network of cranial sutures in the mammal skull. We combined two computational biomechanical methods, multibody dynamics analysis and finite element analysis, to simulate biting in a rat skull and compared models with and without cranial sutures. Our results show that including complex sutures in the rat model does not substantially change overall strain gradients across the cranium, particularly strain magnitudes in the bones overlying the brain. However, local variations in strain magnitudes and patterns can be observed in areas close to the sutures. These results show that, during feeding, sutures may be more important in some regions than others. Sutures should therefore be included in models that require accurate local strain magnitudes and patterns of cranial strain, particularly if models are developed for analysis of specific regions, such as the temporomandibular joint or zygomatic arch. Our results suggest that, for mammalian skulls, cranial sutures might be more important for allowing brain expansion during growth than redistributing biting loads across the cranium in adults.
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Affiliation(s)
- Alana C Sharp
- Department of Musculoskeletal and Ageing Sciences, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, UK.,Department of Cell and Developmental Biology, University College London, London, UK
| | - Hugo Dutel
- Department of Engineering, University of Hull, Hull, UK.,Faculty of Science, School of Earth Sciences, University of Bristol, Bristol, UK
| | | | - Flora Gröning
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Aberdeen, UK
| | - Nick Crumpton
- Department of Cell and Developmental Biology, University College London, London, UK
| | | | - Susan E Evans
- Department of Cell and Developmental Biology, University College London, London, UK
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Smith AL, Davis J, Panagiotopoulou O, Taylor AB, Robinson C, Ward CV, Kimbel WH, Alemseged Z, Ross CF. Does the model reflect the system? When two-dimensional biomechanics is not 'good enough'. J R Soc Interface 2023; 20:20220536. [PMID: 36695017 PMCID: PMC9874278 DOI: 10.1098/rsif.2022.0536] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 12/16/2022] [Indexed: 01/26/2023] Open
Abstract
Models are mathematical representations of systems, processes or phenomena. In biomechanics, finite-element modelling (FEM) can be a powerful tool, allowing biologists to test form-function relationships in silico, replacing or extending results of in vivo experimentation. Although modelling simplifications and assumptions are necessary, as a minimum modelling requirement the results of the simplified model must reflect the biomechanics of the modelled system. In cases where the three-dimensional mechanics of a structure are important determinants of its performance, simplified two-dimensional modelling approaches are likely to produce inaccurate results. The vertebrate mandible is one among many three-dimensional anatomical structures routinely modelled using two-dimensional FE analysis. We thus compare the stress regimes of our published three-dimensional model of the chimpanzee mandible with a published two-dimensional model of the chimpanzee mandible and identify several fundamental differences. We then present a series of two-dimensional and three-dimensional FE modelling experiments that demonstrate how three key modelling parameters, (i) dimensionality, (ii) symmetric geometry, and (iii) constraints, affect deformation and strain regimes of the models. Our results confirm that, in the case of the primate mandible (at least), two-dimensional FEM fails to meet this minimum modelling requirement and should not be used to draw functional, ecological or evolutionary conclusions.
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Affiliation(s)
- Amanda L. Smith
- Department of Organismal Biology and Anatomy, University of Chicago, 1027 East 57th St, Chicago, IL 60637, USA
- Department of Anatomy, Pacific Northwest University of Health Sciences, Yakima, WA 90981, USA
| | - Julian Davis
- Department of Engineering, University of Southern Indiana, 8600 University Blvd, Evansville, IN 47712, USA
| | - Olga Panagiotopoulou
- Department of Anatomy & Developmental Biology, Monash Biomedicine Discovery Institute, Faculty of Medicine Nursing and Health Sciences, Monash University, Clayton, Melbourne, Victoria 3800, Australia
| | | | - Chris Robinson
- Department of Biological Sciences, Bronx Community College, Bronx, NY 10453, USA
- Doctoral Program in Anthropology, The Graduate Center, City University of New York, New York, NY 10016, USA
| | - Carol V. Ward
- Department of Pathology & Anatomical Sciences, One Hospital Drive, University of Missouri, Columbia, MO 65212, USA
| | - William H. Kimbel
- School of Human Evolution and Social Change, Arizona State University, Tempe, AZ 85287-4101, USA
| | - Zeresenay Alemseged
- Department of Organismal Biology and Anatomy, University of Chicago, 1027 East 57th St, Chicago, IL 60637, USA
| | - Callum F. Ross
- Department of Anatomy, Pacific Northwest University of Health Sciences, Yakima, WA 90981, USA
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Haravu PN, Abraha HM, Shang M, Iriarte-Diaz J, Taylor AB, Reid RR, Ross CF, Panagiotopoulou O. Macaca mulatta is a good model for human mandibular fixation research. ROYAL SOCIETY OPEN SCIENCE 2022; 9:220438. [PMID: 36405636 PMCID: PMC9667141 DOI: 10.1098/rsos.220438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 10/26/2022] [Indexed: 06/16/2023]
Abstract
Biomechanical and clinical studies have yet to converge on the optimal fixation technique for angle fractures, one of the most common and controversial fractures in terms of fixation approach. Prior pre-clinical studies have used a variety of animal models and shown abnormal strain environments exacerbated by less rigid (single-plate) Champy fixation and chewing on the side opposite the fracture (contralateral chewing). However, morphological differences between species warrant further investigation to ensure that these findings are translational. Here we present the first study to use realistically loaded finite-element models to compare the biomechanical behaviour of human and macaque mandibles pre- and post-fracture and fixation. Our results reveal only small differences in deformation and strain regimes between human and macaque mandibles. In the human model, more rigid biplanar fixation better approximated physiologically healthy global bone strains and moments around the mandible, and also resulted in less interfragmentary strain than less rigid Champy fixation. Contralateral chewing exacerbated deviations in strain, moments and interfragmentary strain, especially under Champy fixation. Our pre- and post-fracture fixation findings are congruent with those from macaques, confirming that rhesus macaques are excellent animal models for biomedical research into mandibular fixation. Furthermore, these findings strengthen the case for rigid biplanar fixation over less rigid one-plate fixation in the treatment of isolated mandibular angle fractures.
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Affiliation(s)
- Pranav N. Haravu
- Department of Surgery, Section of Plastic Surgery, The University of Chicago Medical Centre, Chicago, IL, USA
| | - Hyab Mehari Abraha
- Monash Biomedicine Discovery Institute, Department of Anatomy and Developmental Biology, Monash University, Victoria, Australia
| | - Michelle Shang
- Department of Surgery, Section of Plastic Surgery, The University of Chicago Medical Centre, Chicago, IL, USA
| | - Jose Iriarte-Diaz
- Department of Biology, The University of the South, Sewanee, TN, USA
| | | | - Russell R. Reid
- Department of Surgery, Section of Plastic Surgery, The University of Chicago Medical Centre, Chicago, IL, USA
| | - Callum F. Ross
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL, USA
| | - Olga Panagiotopoulou
- Monash Biomedicine Discovery Institute, Department of Anatomy and Developmental Biology, Monash University, Victoria, Australia
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Mitchell DR, Wroe S, Ravosa MJ, Menegaz RA. More Challenging Diets Sustain Feeding Performance: Applications Toward the Captive Rearing of Wildlife. Integr Org Biol 2021; 3:obab030. [PMID: 34888486 PMCID: PMC8653637 DOI: 10.1093/iob/obab030] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 10/09/2021] [Accepted: 10/20/2021] [Indexed: 11/14/2022] Open
Abstract
The rescue and rehabilitation of young fauna is of substantial importance to conservation. However, it has been suggested that incongruous diets offered in captive environments may alter craniofacial morphology and hinder the success of reintroduced animals. Despite these claims, to what extent dietary variation throughout ontogeny impacts intrapopulation cranial biomechanics has not yet been tested. Here, finite element models were generated from the adult crania of 40 rats (n = 10 per group) that were reared on 4 different diet regimes and stress magnitudes compared during incisor bite simulations. The diets consisted of (1) exclusively hard pellets from weaning, (2) exclusively soft ground pellet meal from weaning, (3) a juvenile switch from pellets to meal, and (4) a juvenile switch from meal to pellets. We hypothesized that a diet of exclusively soft meal would result in the weakest adult skulls, represented by significantly greater stress magnitudes at the muzzle, palate, and zygomatic arch. Our hypothesis was supported at the muzzle and palate, indicating that a diet limited to soft food inhibits bone deposition throughout ontogeny. This finding presents a strong case for a more variable and challenging diet during development. However, rather than the "soft" diet group resulting in the weakest zygomatic arch as predicted, this region instead showed the highest stress among rats that switched as juveniles from hard pellets to soft meal. We attribute this to a potential reduction in number and activity of osteoblasts, as demonstrated in studies of sudden and prolonged disuse of bone. A shift to softer foods in captivity, during rehabilitation after injury in the wild for example, can therefore be detrimental to healthy development of the skull in some growing animals, potentially increasing the risk of injury and impacting the ability to access full ranges of wild foods upon release. We suggest captive diet plans consider not just nutritional requirements but also food mechanical properties when rearing wildlife to adulthood for reintroduction.
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Affiliation(s)
- D Rex Mitchell
- Center for Anatomical Sciences, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Stephen Wroe
- School of Environmental and Rural Science, University of New England, Armidale, NSW 2351, Australia
| | - Matthew J Ravosa
- Departments of Biological Sciences, Aerospace and Mechanical Engineering, and Anthropology, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Rachel A Menegaz
- Center for Anatomical Sciences, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
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Türp JC, Simonek M, Dagassan D. Bone apposition at the mandibular angles as a radiological sign of bruxism: a retrospective study. BMC Oral Health 2021; 21:537. [PMID: 34663284 PMCID: PMC8522088 DOI: 10.1186/s12903-021-01804-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 08/29/2021] [Indexed: 11/23/2022] Open
Abstract
Background The main objective of this investigation was to determine on panoramic radiographs the prevalence of macroscopically visible alterations (bone apposition in combination with directional change) in the mandibular angle region in bruxism patients. Another aim was to describe and detect different morphological characteristics of the jaw angles. Methods Two hundred panoramic radiographs were studied: 100 images of adults with clinically diagnosed bruxism (73 women, 27 men, age range 21–83 years), 100 images of a comparison group consisting of adolescents (66 girls, 34 boys, age range 12–18 years). Results The morphological changes of the 400 jaw angles could be classified into four degrees. In the adult group, almost half of mandibular angles showed bone apposition. Conversely, the prevalence in the control group was zero. The localization of the appositions corresponds to the insertions of the masseter and medial pterygoid muscles at the mandibular angle. Conclusions The bone apposition at the mandibular angles should be interpreted as a functional adaptation to the long-term increased loads that occur during the contraction of the jaw closing muscles due to bruxism. Hence, radiologically diagnosed bone apposition may serve as an indication or confirmation of bruxism.
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Affiliation(s)
- Jens Christoph Türp
- Division of Temporomandibular Disorders and Orofacial Pain, Department of Oral Health & Medicine, University Center for Dental Medicine Basel (UZB), University of Basel, Basel, Switzerland.
| | - Michelle Simonek
- Department of Oral Surgery, University Center for Dental Medicine Basel, University of Basel, Basel, Switzerland
| | - Dorothea Dagassan
- Center for Dental Imaging, University Center for Dental Medicine Basel, University of Basel, Basel, Switzerland
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11
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Mehari Abraha H, Iriarte‐Diaz J, Reid RR, Ross CF, Panagiotopoulou O. Fracture Fixation Technique and Chewing Side Impact Jaw Mechanics in Mandible Fracture Repair. JBMR Plus 2021; 6:e10559. [PMID: 35079674 PMCID: PMC8770999 DOI: 10.1002/jbm4.10559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 08/17/2021] [Accepted: 09/07/2021] [Indexed: 12/04/2022] Open
Abstract
Lower jaw (mandible) fractures significantly impact patient health and well‐being due to pain and difficulty eating, but the best technique for repairing the most common subtype—angle fractures—and rehabilitating mastication is unknown. Our study is the first to use realistic in silico simulation of chewing to quantify the effects of Champy and biplanar techniques of angle fracture fixation. We show that more rigid, biplanar fixation results in lower strain magnitudes in the miniplates, the bone around the screws, and in the fracture zone, and that the mandibular strain regime approximates the unfractured condition. Importantly, the strain regime in the fracture zone is affected by chewing laterality, suggesting that both fixation type and the patient's post‐fixation masticatory pattern—ipsi‐ or contralateral to the fracture— impact the bone healing environment. Our study calls for further investigation of the impact of fixation technique on chewing behavior. Research that combines in vivo and in silico approaches can link jaw mechanics to bone healing and yield more definitive recommendations for fixation, hardware, and postoperative rehabilitation to improve outcomes. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
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Affiliation(s)
- Hyab Mehari Abraha
- Monash Biomedicine Discovery Institute, Department of Anatomy and Developmental Biology Monash University Melbourne Australia
| | | | - Russell R Reid
- Department of Surgery, Section of Plastic Surgery The University of Chicago Medical Centre Chicago IL USA
| | - Callum F Ross
- Department of Organismal Biology and Anatomy University of Chicago Chicago IL USA
| | - Olga Panagiotopoulou
- Monash Biomedicine Discovery Institute, Department of Anatomy and Developmental Biology Monash University Melbourne Australia
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12
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Holmes M, Taylor AB. The influence of jaw-muscle fibre-type phenotypes on estimating maximum muscle and bite forces in primates. Interface Focus 2021; 11:20210009. [PMID: 34938437 PMCID: PMC8361599 DOI: 10.1098/rsfs.2021.0009] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/09/2021] [Indexed: 02/06/2023] Open
Abstract
Numerous anthropological studies have been aimed at estimating jaw-adductor muscle forces, which, in turn, are used to estimate bite force. While primate jaw adductors show considerable intra- and intermuscular heterogeneity in fibre types, studies generally model jaw-muscle forces by treating the jaw adductors as either homogeneously slow or homogeneously fast muscles. Here, we provide a novel extension of such studies by integrating fibre architecture, fibre types and fibre-specific tensions to estimate maximum muscle forces in the masseter and temporalis of five anthropoid primates: Sapajus apella (N = 3), Cercocebus atys (N = 4), Macaca fascicularis (N = 3), Gorilla gorilla (N = 1) and Pan troglodytes (N = 2). We calculated maximum muscle forces by proportionally adjusting muscle physiological cross-sectional areas by their fibre types and associated specific tensions. Our results show that the jaw adductors of our sample ubiquitously express MHC α-cardiac, which has low specific tension, and hybrid fibres. We find that treating the jaw adductors as either homogeneously slow or fast muscles potentially overestimates average maximum muscle forces by as much as approximately 44%. Including fibre types and their specific tensions is thus likely to improve jaw-muscle and bite force estimates in primates.
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Affiliation(s)
- Megan Holmes
- Department of Family Medicine and Community Health, Duke University School of Medicine, Durham, NC, USA
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Smith AL, Robinson C, Taylor AB, Panagiotopoulou O, Davis J, Ward CV, Kimbel WH, Alemseged Z, Ross CF. Comparative biomechanics of the Pan and Macaca mandibles during mastication: finite element modelling of loading, deformation and strain regimes. Interface Focus 2021; 11:20210031. [PMID: 34938438 PMCID: PMC8361577 DOI: 10.1098/rsfs.2021.0031] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/09/2021] [Indexed: 10/17/2023] Open
Abstract
The mechanical behaviour of the mandibles of Pan and Macaca during mastication was compared using finite element modelling. Muscle forces were calculated using species-specific measures of physiological cross-sectional area and scaled using electromyographic estimates of muscle recruitment in Macaca. Loading regimes were compared using moments acting on the mandible and strain regimes were qualitatively compared using maps of principal, shear and axial strains. The enlarged and more vertically oriented temporalis and superficial masseter muscles of Pan result in larger sagittal and transverse bending moments on both working and balancing sides, and larger anteroposterior twisting moments on the working side. The mandible of Pan experiences higher principal strain magnitudes in the ramus and mandibular prominence, higher transverse shear strains in the top of the symphyseal region and working-side corpus, and a predominance of sagittal bending-related strains in the balancing-side mandible. This study lays the foundation for a broader comparative study of Hominidae mandibular mechanics in extant and fossil hominids using finite element modelling. Pan's larger and more vertical masseter and temporalis may make it a more suitable model for hominid mandibular biomechanics than Macaca.
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Affiliation(s)
- Amanda L. Smith
- Department of Anatomy, Pacific Northwest University of Health Sciences, 200 University Parkway, Yakima, WA 98901, USA
- Department of Organismal Biology and Anatomy, University of Chicago, 1027 East 57th Street, Chicago, IL 60637, USA
| | - Chris Robinson
- Department of Biological Sciences, Bronx Community College, Bronx, NY 10453, USA
| | | | - Olga Panagiotopoulou
- Department of Anatomy and Developmental Biology, Monash Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Melbourne, Victoria 3800, Australia
| | - Julian Davis
- Department of Engineering, University of Southern Indiana, 8600 University Boulevard, Evansville, IN 47712, USA
| | - Carol V. Ward
- Department of Pathology and Anatomical Sciences, One Hospital Drive, University of Missouri, Columbia, MO 65212, USA
| | - William H. Kimbel
- School of Human Evolution and Social Change, Arizona State University, Tempe, AZ 85287-4101, USA
| | - Zeresenay Alemseged
- Department of Organismal Biology and Anatomy, University of Chicago, 1027 East 57th Street, Chicago, IL 60637, USA
| | - Callum F. Ross
- Department of Organismal Biology and Anatomy, University of Chicago, 1027 East 57th Street, Chicago, IL 60637, USA
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