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Popowics TE, Hwang I, Lu J, Nguyen T, Sample M, Sangster A, Tang D, Dennison CR, Romanyk DL, Rafferty K, Greenlee G. In vivo measurement of strain in the periodontal space of pig (Sus scrofa) incisors using in-fiber Bragg sensors. J Morphol 2024; 285:e21738. [PMID: 38783683 DOI: 10.1002/jmor.21738] [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: 12/20/2023] [Revised: 05/08/2024] [Accepted: 05/13/2024] [Indexed: 05/25/2024]
Abstract
The incisor teeth in pigs, Sus scrofa, function in association with a disc-shaped snout to explore the environment for potential food. Understanding how mechanical loading applied to the tooth deforms the periodontal ligament (PDL) is important to determining the role of periodontal mechanoreceptors during food exploration and feeding. The objective of this study was to use fiber Bragg (FBG) sensors to measure strain in vivo within the PDL space of pig incisors. The central mandibular incisors of pigs underwent spring loaded lingual tipping during FBG strain recording within the labial periodontal space. FBG sensors were placed within the periodontal space of the central mandibular incisors of ~2-3-month-old farm pigs. The magnitude and orientation of spring loads are expected to mimic incisor contact with food. During incisor tipping with load calibrated springs, FBG strains in vitro (N = 6) and in vivo (N = 6) recorded at comparable load levels overlapped in range (-10-20 με). Linear regressions between peak FBG strains, that is, the highest recorded strain value, and baseline strains, that is, strain without applied spring load, were significant across all in vivo experiments (peak strain at 200 g vs. baseline, p = .04; peak strain at 2000 g vs. baseline p = .03; peak strain at 2000 g vs. 200 g, p = .004). These linear relationships indicate that on a per experiment basis, the maximum measured strain at different spring loads showed predictable differences. A Friedman test of the absolute value of peak strain confirmed the significant increase in strain between baseline, 200 g, and 2000 g spring activation (p = .02). Mainly compressive strains were recorded in the labial PDL space and increases in spring load applied in vivo generated increases in FBG strain measurements. These results demonstrate the capacity for FBG sensors to be used in vivo to assess transmission of occlusal loads through the periodontium. PDL strain is associated with mechanoreceptor stimulation and is expected to affect the functional morphology of the incisors. The overall low levels of strain observed may correspond with the robust functional morphology of pig incisors and the tendency for pigs to encounter diverse foods and substrates during food exploration.
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Affiliation(s)
- Tracy E Popowics
- Department of Oral Health Sciences, University of Washington, Seattle, Washington, USA
| | - Isabelle Hwang
- Department of Oral Health Sciences, University of Washington School of Dentistry, University of Washington, Seattle, Washington, USA
| | - Jason Lu
- Department of Oral Health Sciences, University of Washington School of Dentistry, University of Washington, Seattle, Washington, USA
| | - Tammy Nguyen
- Department of Oral Health Sciences, University of Washington School of Dentistry, University of Washington, Seattle, Washington, USA
| | - Morgan Sample
- Department of Oral Health Sciences, University of Washington School of Dentistry, University of Washington, Seattle, Washington, USA
| | - Anissa Sangster
- Department of Oral Health Sciences, University of Washington School of Dentistry, University of Washington, Seattle, Washington, USA
| | - Derrick Tang
- Department of Oral Health Sciences, University of Washington, Seattle, Washington, USA
| | | | - Dan L Romanyk
- Department of Mechanical Engineering, University of Alberta, Edmonton, AB, Canada
| | - Katherine Rafferty
- Department of Orthodontics, University of Washington, Seattle, Washington, USA
| | - Geoffrey Greenlee
- Department of Orthodontics, University of Washington, Seattle, Washington, USA
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2
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Armijo L, Mancl L, Dennison CR, Houg K, Romanyk D, Popowics T. In-fiber Bragg sensor measurements assess fluid effects on strain in the periodontal space of an ex-vivo swine incisor complex under mechanical loading. J Biomech 2023; 157:111729. [PMID: 37473706 DOI: 10.1016/j.jbiomech.2023.111729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 06/14/2023] [Accepted: 07/14/2023] [Indexed: 07/22/2023]
Abstract
The purpose of this study is to determine whether in-fiber Bragg grating (FBG) sensors detect changes within the periodontal ligament (PDL) of ex-vivo swine tooth-PDL-bone complex (TPBC) when manipulating fluid content. Recording strain will allow for a better understanding of the biomechanics of viscoelastic load transfer from the tooth to the PDL during chewing and/or orthodontic tooth movement, as well as replication of these dynamics in regenerated PDL tissues. FBG sensors placed within the PDL of swine incisor teeth were used to measure strain resulting from an intrusive load. Specimens were mounted in a custom platform within an MTS machine and a compressive load was applied at 0.3 mm/s to a depth of 0.5 mm and held for 10 s. Median peak strain and load and median absolute deviation (MAD) were compared: dry vs. saline (n = 19) with bias-corrected bootstrap 95% CI. Dry vs. saline conditions did not statistically differ (median peaks of 5με, 103-105 N) and recorded strains showed high repeatability (MAD of 0.82με, 0.72με, respectively). FBG sensors did not detect the fluid changes in this study, suggesting that the deformation of tissues in the PDL space collectively determine FBG strain in response to tooth loading. The repeatability of measurements demonstrates the potential for FBG sensors to assess the strain in the PDL space of an in vivo swine model.
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Affiliation(s)
- Leigh Armijo
- Dept. of Orthodontics, University of Washington School of Dentistry, Seattle, WA 98195, USA.
| | - Lloyd Mancl
- Dept. of Oral Health Sciences, University of Washington School of Dentistry, Seattle, WA 98195, USA.
| | | | - Kathryn Houg
- Dept. of Mechanical Engineering and School of Dentistry, University of Alberta, Edmonton, Alberta, Canada.
| | - Dan Romanyk
- Dept. of Mechanical Engineering and School of Dentistry, University of Alberta, Edmonton, Alberta, Canada.
| | - Tracy Popowics
- Box 357475, Dept. of Oral Health Sciences, 1959 Pacific Ave. NE, University of Washington School of Dentistry, Seattle, WA 98195, USA.
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Wang B, Nguyen N, Kang M, Srirangapatanam S, Connelly S, Souza R, Ho SP. Contact ratio and adaptations in the maxillary and mandibular dentoalveolar joints in rats and human clinical analogs. J Mech Behav Biomed Mater 2022; 136:105485. [PMID: 36209587 DOI: 10.1016/j.jmbbm.2022.105485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Revised: 09/19/2022] [Accepted: 09/21/2022] [Indexed: 11/19/2022]
Abstract
Spatial maps of function-based contact areas and resulting mechanical strains in bones of intact fibrous joints in preclinical small-scale animal models are limited. Functional imaging in situ on intact dentoalveolar fibrous joints (DAJs) in hemimandibles and hemimaxillae harvested from 10 male Sprague-Dawley rats (N = 5 at 12 weeks, N = 5 at 20 weeks) was performed in this study. Physical features including bone volume fraction (BVF), bone pore diameter and pore density, and cementum fraction (CF) of the molars in the maxillary and mandibular joints were evaluated. Biomechanical testing in situ provided estimates of joint stiffness, changes in periodontal ligament spaces (PDL-space) between the molar and bony socket, and thereby localization of contact area in the respective joints. Contact area localization revealed mechanically stressed interradicular and apical regions in the joints. These anatomy-specific contact stresses in maxillary and mandibular joints were correlated with the physical features and resulting strains in interradicular and bony socket compartments. The mandibular joint spaces, in general, were higher than maxillary, and this trend was consistent with age (younger loaded: Mn - 134 ± 55 μm, Mx - 110 ± 47 μm; older loaded: Mn - 122 ± 49 μm, Mx - 105 ± 48 μm). However, a significant decrease (P < 0.05) in mandibular and maxillary joint spaces with age (younger unloaded: Mn - 147 ± 51 μm; Mx - 125 ± 42 μm; older unloaded: Mn - 134 ± 46 μm; Mx - 116 ± 44 μm) was observed. The bone volume fraction (BVF) of mandibular interradicular bone (IR bone) increased significantly with age (P < 0.05) with the percent porosity of coronal mandibular bone lower than its maxillary counterpart. The contact ratio (contact area to total surface area) of maxillary teeth was significantly greater (P < 0.05) than mandibular teeth; both maxillary interradicular and apical contact ratios (IR bone: 41%, 56%; Apical bone: 4%, 12%) increased with age, and were higher than the mandibular (IR bone: 19%, 44%; Apical bone: 1%, 4%) counterpart. Resulting higher but uniform strains in maxillary bone contrasted with lower but higher variance in mandibular strains at a younger age. Anatomy-specific colocalization of physical properties and functional strains in bone provided insights into form-guided adaptive dominance of the maxilla compared to material property-guided adaptive dominance of the mandible. These age-related trends from the preclinical animal model paralleled with age- and tooth position-specific variabilities in mandibular craniofacial bones of adolescent and adult patients following orthodontic treatment.
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Affiliation(s)
- Bo Wang
- State Key Laboratory of Structural Analysis for Industrial Equipment, Department of Engineering Mechanics, Dalian University of Technology, Dalian, 116023, PR China; International Research Center for Computational Mechanics, Dalian University of Technology, Dalian, 116023, PR China; Ningbo Institute of Dalian University of Technology, Ningbo, 315016, PR China; DUT-BSU Joint Institute, Dalian University of Technology, 116023, PR China; Division of Preclinical Education, Biomaterials & Engineering, Department of Preventive and Restorative Dental Sciences, School of Dentistry, University of California San Francisco, CA 94143, USA
| | - Nam Nguyen
- Division of Preclinical Education, Biomaterials & Engineering, Department of Preventive and Restorative Dental Sciences, School of Dentistry, University of California San Francisco, CA 94143, USA
| | - Misun Kang
- Division of Preclinical Education, Biomaterials & Engineering, Department of Preventive and Restorative Dental Sciences, School of Dentistry, University of California San Francisco, CA 94143, USA
| | | | - Stephen Connelly
- Division of Oral Surgery, Department of Orofacial Sciences, School of Dentistry, University of California San Francisco, CA, 94143, USA
| | - Richard Souza
- Departments of Physical Therapy and Rehabilitation Science, Radiology and Biomedical Orthopaedic Surgery, School of Medicine, University of California San Francisco, CA, 94143, USA
| | - Sunita P Ho
- Division of Preclinical Education, Biomaterials & Engineering, Department of Preventive and Restorative Dental Sciences, School of Dentistry, University of California San Francisco, CA 94143, USA.
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Dall'Ara E, Bodey AJ, Isaksson H, Tozzi G. A practical guide for in situ mechanical testing of musculoskeletal tissues using synchrotron tomography. J Mech Behav Biomed Mater 2022; 133:105297. [PMID: 35691205 DOI: 10.1016/j.jmbbm.2022.105297] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Revised: 05/03/2022] [Accepted: 05/25/2022] [Indexed: 02/07/2023]
Abstract
Musculoskeletal tissues are complex hierarchical materials where mechanical response is linked to structural and material properties at different dimensional levels. Therefore, high-resolution three-dimensional tomography is very useful for assessing tissue properties at different scales. In particular, Synchrotron Radiation micro-Computed Tomography (SR-microCT) has been used in several applications to analyze the structure of bone and biomaterials. In the past decade the development of digital volume correlation (DVC) algorithms applied to SR-microCT images and its combination with in situ mechanical testing (four-dimensional imaging) have allowed researchers to visualise, for the first time, the deformation of musculoskeletal tissues and their interaction with biomaterials under different loading scenarios. However, there are several experimental challenges that make these measurements difficult and at high risk of failure. Challenges relate to sample preparation, imaging parameters, loading setup, accumulated tissue damage for multiple tomographic acquisitions, reconstruction methods and data processing. Considering that access to SR-microCT facilities is usually associated with bidding processes and long waiting times, the failure of these experiments could notably slow down the advancement of this research area and reduce its impact. Many of the experimental failures can be avoided with increased experience in performing the tests and better guidelines for preparation and execution of these complex experiments; publication of negative results could help interested researchers to avoid recurring mistakes. Therefore, the goal of this article is to highlight the potential and pitfalls in the design and execution of in situ SR-microCT experiments, involving multiple scans, of musculoskeletal tissues for the assessment of their structural and/or mechanical properties. The advice and guidelines that follow should improve the success rate of this type of experiment, allowing the community to reach higher impact more efficiently.
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Affiliation(s)
- E Dall'Ara
- Department of Oncology and Metabolism, Mellanby Centre for Bone Research, University of Sheffield, UK; INSIGNEO Institute for in Silico Medicine, University of Sheffield, UK.
| | | | - H Isaksson
- Department of Biomedical Engineering, Lund University, Lund, Sweden
| | - G Tozzi
- School of Engineering, London South Bank University, London, UK
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Dall'Ara E, Tozzi G. Digital volume correlation for the characterization of musculoskeletal tissues: Current challenges and future developments. Front Bioeng Biotechnol 2022; 10:1010056. [PMID: 36267445 PMCID: PMC9577231 DOI: 10.3389/fbioe.2022.1010056] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 09/20/2022] [Indexed: 11/13/2022] Open
Abstract
Biological tissues are complex hierarchical materials, difficult to characterise due to the challenges associated to the separation of scale and heterogeneity of the mechanical properties at different dimensional levels. The Digital Volume Correlation approach is the only image-based experimental approach that can accurately measure internal strain field within biological tissues under complex loading scenarios. In this minireview examples of DVC applications to study the deformation of musculoskeletal tissues at different dimensional scales are reported, highlighting the potential and challenges of this relatively new technique. The manuscript aims at reporting the wide breath of DVC applications in the past 2 decades and discuss future perspective for this unique technique, including fast analysis, applications on soft tissues, high precision approaches, and clinical applications.
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Affiliation(s)
- Enrico Dall'Ara
- Department of Oncology and Metabolism, Mellanby Centre for Bone Research, University of Sheffield, Sheffield, United Kingdom.,INSIGNEO Institute for in Silico Medicine, University of Sheffield, Sheffield, United Kingdom
| | - Gianluca Tozzi
- School of Engineering, University of Greenwich, Chatham Maritime, United Kingdom
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Dieterle MP, Husari A, Steinberg T, Wang X, Ramminger I, Tomakidi P. From the Matrix to the Nucleus and Back: Mechanobiology in the Light of Health, Pathologies, and Regeneration of Oral Periodontal Tissues. Biomolecules 2021; 11:824. [PMID: 34073044 PMCID: PMC8228498 DOI: 10.3390/biom11060824] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 05/25/2021] [Accepted: 05/27/2021] [Indexed: 02/07/2023] Open
Abstract
Among oral tissues, the periodontium is permanently subjected to mechanical forces resulting from chewing, mastication, or orthodontic appliances. Molecularly, these movements induce a series of subsequent signaling processes, which are embedded in the biological concept of cellular mechanotransduction (MT). Cell and tissue structures, ranging from the extracellular matrix (ECM) to the plasma membrane, the cytosol and the nucleus, are involved in MT. Dysregulation of the diverse, fine-tuned interaction of molecular players responsible for transmitting biophysical environmental information into the cell's inner milieu can lead to and promote serious diseases, such as periodontitis or oral squamous cell carcinoma (OSCC). Therefore, periodontal integrity and regeneration is highly dependent on the proper integration and regulation of mechanobiological signals in the context of cell behavior. Recent experimental findings have increased the understanding of classical cellular mechanosensing mechanisms by both integrating exogenic factors such as bacterial gingipain proteases and newly discovered cell-inherent functions of mechanoresponsive co-transcriptional regulators such as the Yes-associated protein 1 (YAP1) or the nuclear cytoskeleton. Regarding periodontal MT research, this review offers insights into the current trends and open aspects. Concerning oral regenerative medicine or weakening of periodontal tissue diseases, perspectives on future applications of mechanobiological principles are discussed.
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Affiliation(s)
- Martin Philipp Dieterle
- Center for Dental Medicine, Division of Oral Biotechnology, Medical Center—University of Freiburg, Faculty of Medicine, University of Freiburg, Hugstetterstr. 55, 79106 Freiburg, Germany; (M.P.D.); (X.W.); (I.R.); (P.T.)
| | - Ayman Husari
- Center for Dental Medicine, Department of Orthodontics, Medical Center—University of Freiburg, Faculty of Medicine, University of Freiburg, Hugstetterstr. 55, 79106 Freiburg, Germany;
- Faculty of Engineering, University of Freiburg, Georges-Köhler-Allee 101, 79110 Freiburg, Germany
| | - Thorsten Steinberg
- Center for Dental Medicine, Division of Oral Biotechnology, Medical Center—University of Freiburg, Faculty of Medicine, University of Freiburg, Hugstetterstr. 55, 79106 Freiburg, Germany; (M.P.D.); (X.W.); (I.R.); (P.T.)
| | - Xiaoling Wang
- Center for Dental Medicine, Division of Oral Biotechnology, Medical Center—University of Freiburg, Faculty of Medicine, University of Freiburg, Hugstetterstr. 55, 79106 Freiburg, Germany; (M.P.D.); (X.W.); (I.R.); (P.T.)
| | - Imke Ramminger
- Center for Dental Medicine, Division of Oral Biotechnology, Medical Center—University of Freiburg, Faculty of Medicine, University of Freiburg, Hugstetterstr. 55, 79106 Freiburg, Germany; (M.P.D.); (X.W.); (I.R.); (P.T.)
| | - Pascal Tomakidi
- Center for Dental Medicine, Division of Oral Biotechnology, Medical Center—University of Freiburg, Faculty of Medicine, University of Freiburg, Hugstetterstr. 55, 79106 Freiburg, Germany; (M.P.D.); (X.W.); (I.R.); (P.T.)
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