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Wang L, Meloro C, Fagan MJ, Kissane RWP, Bates KT, Askew GN, Watson PJ. Regional variation of the cortical and trabecular bone material properties in the rabbit skull. PLoS One 2024; 19:e0298621. [PMID: 38412158 PMCID: PMC10898762 DOI: 10.1371/journal.pone.0298621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 01/27/2024] [Indexed: 02/29/2024] Open
Abstract
The material properties of some bones are known to vary with anatomical location, orientation and position within the bone (e.g., cortical and trabecular bone). Details of the heterogeneity and anisotropy of bone is an important consideration for biomechanical studies that apply techniques such as finite element analysis, as the outcomes will be influenced by the choice of material properties used. Datasets detailing the regional variation of material properties in the bones of the skull are sparse, leaving many finite element analyses of skulls no choice but to employ homogeneous, isotropic material properties, often using data from a different species to the one under investigation. Due to the growing significance of investigating the cranial biomechanics of the rabbit in basic science and clinical research, this study used nanoindentation to measure the elastic modulus of cortical and trabecular bone throughout the skull. The elastic moduli of cortical bone measured in the mediolateral and ventrodorsal direction were found to decrease posteriorly through the skull, while it was evenly distributed when measured in the anteroposterior direction. Furthermore, statistical tests showed that the variation of elastic moduli between separate regions (anterior, middle and posterior) of the skull were significantly different in cortical bone, but was not in trabecular bone. Elastic moduli measured in different orthotropic planes were also significantly different, with the moduli measured in the mediolateral direction consistently lower than that measured in either the anteroposterior or ventrodorsal direction. These findings demonstrate the significance of regional and directional variation in cortical bone elastic modulus, and therefore material properties in finite element models of the skull, particularly those of the rabbit, should consider the heterogeneous and orthotropic properties of skull bone when possible.
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Affiliation(s)
- Linje Wang
- Structural Biomechanics, Department of Civil and Environmental Engineering, Imperial College London, London, United Kingdom
- School of Engineering, University of Hull, Hull, United Kingdom
| | - Carlo Meloro
- Research Centre in Evolutionary Anthropology and Palaeoecology, School of Biological and Environmental Sciences, Liverpool John Moores University, Liverpool, United Kingdom
| | - Michael J Fagan
- School of Engineering, University of Hull, Hull, United Kingdom
| | - Roger W P Kissane
- Department of Musculoskeletal & Ageing Science, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Karl T Bates
- Department of Musculoskeletal & Ageing Science, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Graham N Askew
- School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
| | - Peter J Watson
- School of Engineering, University of Hull, Hull, United Kingdom
- Institute of Medical and Biological Engineering, School of Mechanical Engineering, University of Leeds, Leeds, United Kingdom
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Dolci C, Cenzato N, Maspero C, Giannini L, Khijmatgar S, Dipalma G, Tartaglia GM, Inchingolo F. Skull Biomechanics and Simplified Cephalometric Lines for the Estimation of Muscular Lines of Action. J Pers Med 2023; 13:1569. [PMID: 38003884 PMCID: PMC10672339 DOI: 10.3390/jpm13111569] [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: 09/12/2023] [Revised: 10/25/2023] [Accepted: 10/30/2023] [Indexed: 11/26/2023] Open
Abstract
Our study introduces a novel cephalometric analysis aimed at facilitating biomechanical simulations by elucidating the intricate relationship between craniofacial morphology and the size and inclination of the masseter muscle (MM) while incorporating muscle values. Our study analyzes the line of action of the MM drawn between the Gonion (Go) and Orbital (Or) points concerning dental and skeletal references (occlusal and Frankfort planes). A total of 510 pre-treatment lateral cephalometric tracings (217 males, 293 females, aged 6-50 years) and lateral Bolton standard tracings were examined. The key parameters investigated include (a) skeletal-cutaneous class (linear distance between projections of points A' and B' on the occlusal plane), (b) the angle between the perpendicular line to the occlusal plane and the Go-Or line at the molar occlusal point, and (c) the angle between the Go-Or line and the Frankfort plane. The assessment of anterior-posterior jaw discrepancy, measured as the skeletal-cutaneous class, ranged from -14.5 to 15.5 mm. Abnormal values were identified in two adolescents, showing no gender- or age-related patterns. The angle between the MM's line of action (Go-Or) and the normal to the occlusal plane averaged 39.3°, while the angle between Go-Or and Po-Or (Frankfort plane) averaged 41.99°. Age had an impact on these angles, with an average 3° decrease in adults and a 4° increase between ages 6 and 50. A weak relationship was observed between sagittal jaw discrepancy and the angle between Go-Or and the Frankfort plane, with about 20% of the variance explained by the anteroposterior maxillary-mandibular relationship. In conclusion, the study presents a cephalometric analysis of the relationship between craniofacial morphology and masseter muscle parameters. It finds that age influences the angles between key reference points, while the skeletal-cutaneous class does not exhibit age- or gender-specific trends. These findings can contribute to a better understanding of craniofacial biomechanics and aid in clinical orthodontic assessments and treatment planning.
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Affiliation(s)
- Claudia Dolci
- Department of Biomedical Sciences for Health, Università Degli Studi di Milano, 20133 Milan, Italy
| | - Niccolò Cenzato
- Fondazione IRCCS Ca’ Granda, Ospedale Maggiore Policlinico, 20122 Milan, Italy; (N.C.)
- Department of Biomedical, Surgical and Dental Sciences, School of Dentistry, Università Degli Studi di Milano, 20100 Milan, Italy
| | - Cinzia Maspero
- Fondazione IRCCS Ca’ Granda, Ospedale Maggiore Policlinico, 20122 Milan, Italy; (N.C.)
- Department of Biomedical, Surgical and Dental Sciences, School of Dentistry, Università Degli Studi di Milano, 20100 Milan, Italy
| | - Lucia Giannini
- Department of Biomedical, Surgical and Dental Sciences, School of Dentistry, Università Degli Studi di Milano, 20100 Milan, Italy
| | - Shahnawaz Khijmatgar
- Fondazione IRCCS Ca’ Granda, Ospedale Maggiore Policlinico, 20122 Milan, Italy; (N.C.)
- Department of Biomedical, Surgical and Dental Sciences, School of Dentistry, Università Degli Studi di Milano, 20100 Milan, Italy
| | - Gianna Dipalma
- Department of Interdisciplinary Medicine, Università Degli Studi di Bari “Aldo Moro”, 70124 Bari, Italy; (G.D.)
| | - Gianluca Martino Tartaglia
- Fondazione IRCCS Ca’ Granda, Ospedale Maggiore Policlinico, 20122 Milan, Italy; (N.C.)
- Department of Biomedical, Surgical and Dental Sciences, School of Dentistry, Università Degli Studi di Milano, 20100 Milan, Italy
| | - Francesco Inchingolo
- Department of Interdisciplinary Medicine, Università Degli Studi di Bari “Aldo Moro”, 70124 Bari, Italy; (G.D.)
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Cox PG, Watson PJ. Masticatory biomechanics of red and grey squirrels ( Sciurus vulgaris and Sciurus carolinensis) modelled with multibody dynamics analysis. ROYAL SOCIETY OPEN SCIENCE 2023; 10:220587. [PMID: 36816846 PMCID: PMC9929510 DOI: 10.1098/rsos.220587] [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: 05/03/2022] [Accepted: 01/26/2023] [Indexed: 06/18/2023]
Abstract
The process of feeding in mammals is achieved by moving the mandible relative to the cranium to bring the teeth into and out of occlusion. This process is especially complex in rodents which have a highly specialized configuration of jaw adductor muscles. Here, we used the computational technique of multi-body dynamics analysis (MDA) to model feeding in the red (Sciurus vulgaris) and grey squirrel (Sciurus carolinensis) and determine the relative contribution of each jaw-closing muscle in the generation of bite forces. The MDA model simulated incisor biting at different gapes. A series of 'virtual ablation experiments' were performed at each gape, whereby the activation of each bilateral pair of muscles was set to zero. The maximum bite force was found to increase at wider gapes. As predicted, the superficial and anterior deep masseter were the largest contributors to bite force, but the temporalis had only a small contribution. Further analysis indicated that the temporalis may play a more important role in jaw stabilization than in the generation of bite force. This study demonstrated the ability of MDA to elucidate details of red and grey squirrel feeding biomechanics providing a complement to data gathered via in vivo experimentation.
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Affiliation(s)
- Philip G. Cox
- Department of Cell and Developmental Biology, University College London, London, UK
- Department of Archaeology, University of York, York, UK
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