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Bell-Hensley A, Beard DC, Feeney K, Zheng H, Jiang Y, Zhang X, Liu J, Gabel H, McAlinden A. Skeletal abnormalities in mice with Dnmt3a missense mutations. Bone 2024; 183:117085. [PMID: 38522809 PMCID: PMC11057337 DOI: 10.1016/j.bone.2024.117085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 03/15/2024] [Accepted: 03/21/2024] [Indexed: 03/26/2024]
Abstract
Overgrowth and intellectual disability disorders in humans are typified by length/height and/or head circumference ≥ 2 standard deviations above the mean as well as intellectual disability and behavioral comorbidities, including autism and anxiety. Tatton-Brown-Rahman Syndrome is one type of overgrowth and intellectual disability disorder caused by heterozygous missense mutations in the DNA methyltransferase 3A (DNMT3A) gene. Numerous DNMT3A mutations have been identified in Tatton-Brown-Rahman Syndrome patients and may be associated with varying phenotype severities of clinical presentation. Two such mutations are the R882H and P904L mutations which result in severe and mild phenotypes, respectively. Mice with paralogous mutations (Dnmt3aP900L/+ and Dnmt3aR878H/+) exhibit overgrowth in their long bones (e.g., femur, humerus), but the mechanisms responsible for their skeletal overgrowth remain unknown. The goal of this study is to characterize skeletal phenotypes in mouse models of Tatton-Brown-Rahman Syndrome and identify potential cellular mechanisms involved in the skeletal overgrowth phenotype. We report that mature mice with the Dnmt3aP900L/+ or Dnmt3aR878H/+ mutation exhibit tibial overgrowth, cortical bone thinning, and weakened bone mechanical properties. Dnmt3aR878H/+ mutants also contain larger bone marrow adipocytes while Dnmt3aP900L/+ mutants show no adipocyte phenotype compared to control animals. To understand the potential cellular mechanisms regulating these phenotypes, growth plate chondrocytes, osteoblasts, and osteoclasts were assessed in juvenile mutant mice using quantitative static histomorphometry and dynamic histomorphometry. Tibial growth plates appeared thicker in mutant juvenile mice, but no changes were observed in osteoblast activity or osteoclast number in the femoral mid-diaphysis. These studies reveal new skeletal phenotypes associated with Tatton-Brown-Rahman Syndrome in mice and provide a rationale to extend clinical assessments of patients with this condition to include bone density and quality testing. These findings may be also informative for skeletal characterization of other mouse models presenting with overgrowth and intellectual disability phenotypes.
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Affiliation(s)
- Austin Bell-Hensley
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Diana C Beard
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, USA
| | - Kathryn Feeney
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Hongjun Zheng
- Department of Orthopaedic Surgery, Washington University in St. Louis, St. Louis, MO, USA
| | - Yunhao Jiang
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Xiyun Zhang
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, USA
| | - Jin Liu
- Department of Orthopaedic Surgery, Washington University in St. Louis, St. Louis, MO, USA
| | - Harrison Gabel
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, USA.
| | - Audrey McAlinden
- Department of Orthopaedic Surgery, Washington University in St. Louis, St. Louis, MO, USA; Department of Cell Biology & Physiology, Washington University in St. Louis, St. Louis, MO, USA; Shriners Hospital for Children - St. Louis, St. Louis, MO, USA.
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2
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Aryal YP, Neupane S, Kwak HJ, An CH, Sohn WJ, Yamamoto H, Kwon TY, Min BK, Kim JY, Cho SJ. Unraveling the structure, chemical composition, and conserved signaling in leech teeth. Anim Cells Syst (Seoul) 2024; 28:272-282. [PMID: 38741948 PMCID: PMC11089927 DOI: 10.1080/19768354.2024.2350736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Accepted: 04/29/2024] [Indexed: 05/16/2024] Open
Abstract
Unlike vertebrates, the number of toothed taxa in invertebrates is very few, with leeches being the only tooth-bearing organisms in the phylum Annelida. Copious studies have been conducted regarding vertebrate teeth; however, studies regarding the structure and function of invertebrate teeth are limited. In this study, the tooth structure of leeches, specifically Hirudo nipponia and Haemadipsa rjukjuana, was revealed, which showed sharp and pointed teeth along the apex of three jaws. Understanding conserved signaling regulations among analogous organs is crucial for uncovering the underlying mechanisms during organogenesis. Therefore, to shed light on the evolutionary perspective of odontogenesis to some extent, we conducted de novo transcriptome analyses using embryonic mouse tooth germs, Hirudo teeth, and Helobdella proboscises to identify conserved signaling molecules involved in tooth development. The selection criteria were particularly based on the presence of tooth-related genes in mice, Hirudo teeth, and Helobdella proboscis, wherein 4113 genes were commonly expressed in all three specimens. Furthermore, the chemical nature of leech teeth was also examined via TEM-EDS to compare the chemical composition with vertebrate teeth. The examination of tissue-specific genetic information and chemical nature between leeches and mice revealed chemical similarities between leech and mice teeth, as well as conserved signaling molecules involved in tooth formation, including Ptpro, Prickle2, and Wnt16. Based on our findings, we propose that leech teeth express signaling molecules conserved in mice and these conserved tooth-specific signaling for dental hard tissue formation in mice would corresponds to the structural formation of the toothed jaw in leeches.
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Affiliation(s)
- Yam Prasad Aryal
- Department of Biological Sciences and Biotechnology, College of Natural Sciences, Chungbuk National University, Cheongju, Korea
| | - Sanjiv Neupane
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, USA
| | - Hee-Jin Kwak
- Department of Biological Sciences and Biotechnology, College of Natural Sciences, Chungbuk National University, Cheongju, Korea
| | - Chang-Hyeon An
- Department of Oral and Maxillofacial Radiology, School of Dentistry, Kyungpook National University, Daegu, Korea
| | - Wern-Joo Sohn
- Pre-Major of Cosmetics and Pharmaceutics, Daegu Haany University, Gyeongsan, Korea
| | - Hitoshi Yamamoto
- Department of Histology and Developmental Biology, Tokyo Dental College, Tokyo, Japan
| | - Tae-Yub Kwon
- Department of Dental Biomaterials, School of Dentistry, Kyungpook National University, Daegu, Korea
| | - Bong-Ki Min
- Center for Research Facilities, Yeungnam University, Gyeongsan, Korea
| | - Jae-Young Kim
- Department of Biochemistry, School of Dentistry, Kyungpook National University, Daegu, Korea
| | - Sung-Jin Cho
- Department of Biological Sciences and Biotechnology, College of Natural Sciences, Chungbuk National University, Cheongju, Korea
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Sakr AH, Nassif MS, El-Korashy DI. Amelogenin-inspired peptide, calcium phosphate solution, fluoride and their synergistic effect on enamel biomimetic remineralization: an in vitro pH-cycling model. BMC Oral Health 2024; 24:279. [PMID: 38413983 PMCID: PMC10898002 DOI: 10.1186/s12903-024-04008-z] [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: 11/06/2023] [Accepted: 02/09/2024] [Indexed: 02/29/2024] Open
Abstract
BACKGROUND Several methods were introduced for enamel biomimetic remineralization that utilize a biomimetic analogue to interact and absorb bioavailable calcium and phosphate ions and induce crystal nucleation on demineralized enamel. Amelogenin is the most predominant enamel matrix protein that is involved in enamel biomineralization. It plays a major role in developing the enamel's hierarchical microstructure. Therefore, this study was conducted to evaluate the ability of an amelogenin-inspired peptide to promote the remineralization potential of fluoride and a supersaturated calcium phosphate solution in treating artificially induced enamel carious lesions under pH-cycling regimen. METHODS Fifty enamel slices were prepared with a window (4*4 mm2 ) on the surface. Five samples were set as control healthy enamel and 45 samples were subjected to demineralization for 3 days. Another 5 samples were set as control demineralized enamel and 40 enamel samples were assigned into 8 experimental groups (n=5) (P/I, P/II, P/III, P/AS, NP/I, NP/II, NP/III and NP/AS) according to peptide treatment (peptide P or non-peptide NP) and remineralizing solution used (I; calcium phosphate solution, II; calcium phosphate fluoride solution, III; fluoride solution and AS; artificial saliva). Samples were then subjected to demineralization/remineralization cycles for 9 days. Samples in all experimental groups were evaluated using Raman spectroscopy for mineral content recovery percentage, microhardness and nanoindentation as healthy, demineralized enamel and after pH-cycling. Data were statistically analysed using two-way repeated measures Anova followed by Bonferroni-corrected post hoc test for pairwise multiple comparisons between groups. Statistical significance was set at p= 0.05. Additionally, XRD, FESEM and EDXS were used for crystal orientation, surface morphology and elemental analysis after pH-cycling. RESULTS Nanocrystals clumped in a directional manner were detected in peptide-treated groups. P/II showed the highest significant mean values in mineral content recovery (63.31%), microhardness (268.81±6.52 VHN), elastic modulus (88.74±2.71 GPa), nanohardness (3.08±0.59 GPa) and the best crystal orientation with I002/I300 (1.87±0.08). CONCLUSION Despite pH changes, the tested peptide was capable of remineralizing enamel with ordered crystals. Moreover, the supplementary use of calcium phosphate fluoride solution with peptide granted an enhancement in enamel mechanical properties after remineralization.
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Affiliation(s)
- Aliaa H Sakr
- Dental Biomaterials, Biomaterials Department, Faculty of Dentistry, Ain-Shams University, Organization of African unity street, El-Qobba Bridge, El-Weili, Cairo, Egypt.
| | - Mohammed Salah Nassif
- Dental Biomaterials, Biomaterials Department, Faculty of Dentistry, Ain-Shams University, Organization of African unity street, El-Qobba Bridge, El-Weili, Cairo, Egypt
| | - Dalia I El-Korashy
- Dental Biomaterials, Biomaterials Department, Faculty of Dentistry, Ain-Shams University, Organization of African unity street, El-Qobba Bridge, El-Weili, Cairo, Egypt
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Kovács K, Váncsa S, Agócs G, Harnos A, Hegyi P, Weninger V, Baross K, Kovács B, Soós G, Kocsis G. Anisotropy, Anatomical Region, and Additional Variables Influence Young's Modulus of Bone: A Systematic Review and Meta-Analysis. JBMR Plus 2023; 7:e10835. [PMID: 38130752 PMCID: PMC10731124 DOI: 10.1002/jbm4.10835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Revised: 08/09/2023] [Accepted: 09/25/2023] [Indexed: 12/23/2023] Open
Abstract
The importance of finite element analysis (FEA) is growing in orthopedic research, especially in implant design. However, Young's modulus (E) values, one of the most fundamental parameters, can range across a wide scale. Therefore, our study aimed to identify factors influencing E values in human bone specimens. We report our systematic review and meta-analysis based on the recommendation of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guideline. We conducted the analysis on November 21, 2021. We included studies investigating healthy human bone specimens and reported on E values regarding demographic data, specimen characteristics, and measurement specifics. In addition, we included study types reporting individual specimen measurements. From the acquired data, we created a cohort in which we performed an exploratory data analysis that included the explanatory variables selected by random forest and regression trees methods, and the comparison of groups using independent samples Welch's t test. A total of 756 entries were included from 48 articles. Eleven different bones of the human body were included in these articles. The range of E values is between 0.008 and 33.7 GPa. The E values were most heavily influenced by the cortical or cancellous type of bone tested. Measuring method (compression, tension, bending, and nanoindentation), the anatomical region within a bone, the position of the bone within the skeleton, and the bone specimen size had a decreasing impact on the E values. Bone anisotropy, specimen condition, patient age, and sex were selected as important variables considering the value of E. On the basis of our results, E values of a bone change with bone characteristics, measurement techniques, and demographic variables. Therefore, the evaluation of FEA should be performed after the standardization of in vitro measurement protocol. © 2023 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)
- Krisztián Kovács
- Department of OrthopaedicsSemmelweis UniversityBudapestHungary
- Centre for Translational MedicineSemmelweis UniversityBudapestHungary
| | - Szilárd Váncsa
- Centre for Translational MedicineSemmelweis UniversityBudapestHungary
- Institute for Translational Medicine, Szentágothai Research Centre, Medical SchoolUniversity of PécsPécsHungary
- Division of Pancreatic Diseases, Heart and Vascular CenterSemmelweis UniversityBudapestHungary
| | - Gergely Agócs
- Centre for Translational MedicineSemmelweis UniversityBudapestHungary
- Department of Biophysics and Radiation BiologySemmelweis UniversityBudapestHungary
| | - Andrea Harnos
- Centre for Translational MedicineSemmelweis UniversityBudapestHungary
- Department of BiostatisticsUniversity of Veterinary MedicineBudapestHungary
| | - Péter Hegyi
- Centre for Translational MedicineSemmelweis UniversityBudapestHungary
- Institute for Translational Medicine, Szentágothai Research Centre, Medical SchoolUniversity of PécsPécsHungary
- Division of Pancreatic Diseases, Heart and Vascular CenterSemmelweis UniversityBudapestHungary
| | - Viktor Weninger
- Department of OrthopaedicsSemmelweis UniversityBudapestHungary
- Centre for Translational MedicineSemmelweis UniversityBudapestHungary
| | - Katinka Baross
- Centre for Translational MedicineSemmelweis UniversityBudapestHungary
| | - Bence Kovács
- Centre for Translational MedicineSemmelweis UniversityBudapestHungary
| | - Gergely Soós
- Centre for Translational MedicineSemmelweis UniversityBudapestHungary
| | - György Kocsis
- Department of OrthopaedicsSemmelweis UniversityBudapestHungary
- Centre for Translational MedicineSemmelweis UniversityBudapestHungary
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Arora D, Taylor EA, King KB, Donnelly E. Increased tissue modulus and hardness in the TallyHO mouse model of early onset type 2 diabetes mellitus. PLoS One 2023; 18:e0287825. [PMID: 37418415 PMCID: PMC10328374 DOI: 10.1371/journal.pone.0287825] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 06/14/2023] [Indexed: 07/09/2023] Open
Abstract
Individuals with type 2 diabetes mellitus (T2DM) have a higher fracture risk compared to those without T2DM despite having higher bone mineral density (BMD). Thus, T2DM may alter other aspects of resistance to fracture beyond BMD such as bone geometry, microarchitecture, and tissue material properties. We characterized the skeletal phenotype and assessed the effects of hyperglycemia on bone tissue mechanical and compositional properties in the TallyHO mouse model of early-onset T2DM using nanoindentation and Raman spectroscopy. Femurs and tibias were harvested from male TallyHO and C57Bl/6J mice at 26 weeks of age. The minimum moment of inertia assessed by micro-computed tomography was smaller (-26%) and cortical porosity was greater (+490%) in TallyHO femora compared to controls. In three-point bending tests to failure, the femoral ultimate moment and stiffness did not differ but post-yield displacement was lower (-35%) in the TallyHO mice relative to that in C57Bl/6J age-matched controls after adjusting for body mass. The cortical bone in the tibia of TallyHO mice was stiffer and harder, as indicated by greater mean tissue nanoindentation modulus (+22%) and hardness (+22%) compared to controls. Raman spectroscopic mineral:matrix ratio and crystallinity were greater in TallyHO tibiae than in C57Bl/6J tibiae (mineral:matrix +10%, p < 0.05; crystallinity +0.41%, p < 0.10). Our regression model indicated that greater values of crystallinity and collagen maturity were associated with reduced ductility observed in the femora of the TallyHO mice. The maintenance of structural stiffness and strength of TallyHO mouse femora despite reduced geometric resistance to bending could potentially be explained by increased tissue modulus and hardness, as observed at the tibia. Finally, with worsening glycemic control, tissue hardness and crystallinity increased, and bone ductility decreased in TallyHO mice. Our study suggests that these material factors may be sentinels of bone embrittlement in adolescents with T2DM.
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Affiliation(s)
- Daksh Arora
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York, United States of America
| | - Erik A. Taylor
- Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, New York, United States of America
| | - Karen B. King
- Department of Orthopedics, University of Colorado School of Medicine, Aurora, Colorado, United States of America
| | - Eve Donnelly
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York, United States of America
- Research Institute, Hospital for Special Surgery, New York, New York, United States of America
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Klarić E, Tarle A, Vukelja J, Soče M, Grego T, Janković B. Remineralization effects of Er,Cr:YSGG and/or bioactive glass on human enamel after radiotherapy-an in vitro study. Lasers Med Sci 2023; 38:65. [PMID: 36746823 DOI: 10.1007/s10103-023-03726-0] [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: 11/17/2021] [Accepted: 01/17/2023] [Indexed: 02/08/2023]
Abstract
The aim was to evaluate the effects of Er,Cr:YSGG and/or bioactive glass 45S5 (BG) on the chemical and physical properties of enamel after radiotherapy. Third molar crowns were cut in half (buccal-lingually), and the mid part of the labial/oral surface was subjected to different protocols. All samples were treated with standard 70 Gy. After radiotherapy, enamel was treated with either Er,Cr:YSGG (2780 nm; pulse 60 μs) and BG or only BG, and control samples were kept in deionized water. Vickers microhardness, scanning electron microscopy (SEM), and characteristic X-ray spectroscopy (EDS) were performed before, after radiotherapy, and after treatment. Analysis of variance (ANOVA) was used. A significant drop in enamel microhardness was observed after radiotherapy (p < 0.001). After Er,Cr:YSGG and BG or BG alone, there was a significant increase in microhardness (p < 0.001), which was on average significantly higher compared to the initial measurements for Er,Cr:YSGG with BG (p < 0.001), but not observed in BG alone (p = 0.331). After radiotherapy, SEM showed increased surface roughness with eroded prisms. Er,Cr:YSGG and BG or BG alone both showed disorderly packed glass particles on the enamel surface. Radiotherapy noticeably reduced the concentrations of calcium and phosphorus. Er,Cr:YSGG and BG treatment increased the concentrations of calcium, sodium, phosphorus, and silicate. BG treatment alone increased the concetration of calcium and phosphorus. Directly induced radiotherapy led to potential damage of enamel, but afterwards treatment with Er,Cr:YSGG laser and BG resulted in a higher increase of enamel microhardness compared to BG alone, reflecting in a possible better remineralization effect.
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Affiliation(s)
- Eva Klarić
- Department of Endodontics and Restorative Dental Medicine, University of Zagreb School of Dental Medicine, Zagreb, Croatia.
| | - Andro Tarle
- Department of Otorhinolaryngology, Head and Neck Surgery, Clinical Hospital Centre "Sestre Milosrdnice", Zagreb, Croatia
| | - Josipa Vukelja
- University of Zagreb School of Dental Medicine, Zagreb, Croatia
| | - Majana Soče
- Department of Oncology, Radiotherapy Unit, University Hospital Centre Zagreb, Zagreb, Croatia
| | - Timor Grego
- Department of Oncology, Radiotherapy Unit, University Hospital Centre Zagreb, Zagreb, Croatia
| | - Bernard Janković
- Department of Endodontics and Restorative Dental Medicine, University of Zagreb School of Dental Medicine, Zagreb, Croatia
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Zhong J, Shibata Y. The structural motifs of mineralized hard tissues from nano- to mesoscale: A future perspective for material science. JAPANESE DENTAL SCIENCE REVIEW 2022; 58:348-356. [DOI: 10.1016/j.jdsr.2022.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 10/21/2022] [Accepted: 11/03/2022] [Indexed: 11/16/2022] Open
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The characterization of bovine compact bone fatigue damage using terahertz spectroscopy. Z Med Phys 2022:S0939-3889(22)00065-4. [PMID: 35764468 DOI: 10.1016/j.zemedi.2022.06.001] [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: 09/18/2021] [Revised: 05/27/2022] [Accepted: 06/01/2022] [Indexed: 11/24/2022]
Abstract
Fatigue can cause cracks to propagate from the micro- to the macroscale, which results in a decrease of Young's modulus of the bone. Non-destructive measurements of bone fatigue damage are of great importance for bone quality assessment and fracture prevention. Unfortunately, there is still a lack of effective nondestructive methods sensitive to the initial deterioration during damage accumulation, particularly in the field of orthopedics and biomechanics. In this study, terahertz spectroscopy was adopted to evaluate microscale bone damage. Specifically, the refractive index and Young's modulus of bone samples subjected to different degrees of fatigue damage were tested at a fixed area. Both parameters are found to decrease in two stages under cycled fatigue loading, which is attributed to the initial onset and subsequent development of microdamage during fatigue loading. The change in refractive index reflects the accumulation of fatigue damage as well as the decrease in Young's modulus.
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Tooth Wear and Tribological Investigations in Dentistry. Appl Bionics Biomech 2022; 2022:2861197. [PMID: 35721235 PMCID: PMC9203238 DOI: 10.1155/2022/2861197] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 05/20/2022] [Accepted: 05/23/2022] [Indexed: 11/25/2022] Open
Abstract
Dental or tooth wear is a physiological process in the life cycle of teeth. Loss of the occlusal surface may cause excessive tooth wear. Several factors may contribute to tooth wear with different intensities and duration in the oral cavity. The oral cavity is generally compared to a tribological system to determine the various types of wear between teeth and restorative materials and assess the amount of dental wear. However, it is challenging to investigate in vitro and in vivo wear owing to the complexity of tooth wear; thus, a clear correlation between in vitro and in vivo data could not be established. This review is aimed at providing an insight into the etiology of tooth wear and tribological investigations in dentistry.
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10
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Faber J, Hinrichsen J, Greiner A, Reiter N, Budday S. Tissue-Scale Biomechanical Testing of Brain Tissue for the Calibration of Nonlinear Material Models. Curr Protoc 2022; 2:e381. [PMID: 35384412 DOI: 10.1002/cpz1.381] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 01/14/2022] [Indexed: 06/14/2023]
Abstract
Brain tissue is one of the most complex and softest tissues in the human body. Due to its ultrasoft and biphasic nature, it is difficult to control the deformation state during biomechanical testing and to quantify the highly nonlinear, time-dependent tissue response. In numerous experimental studies that have investigated the mechanical properties of brain tissue over the last decades, stiffness values have varied significantly. One reason for the observed discrepancies is the lack of standardized testing protocols and corresponding data analyses. The tissue properties have been tested on different length and time scales depending on the testing technique, and the corresponding data have been analyzed based on simplifying assumptions. In this review, we highlight the advantage of using nonlinear continuum mechanics based modeling and finite element simulations to carefully design experimental setups and protocols as well as to comprehensively analyze the corresponding experimental data. We review testing techniques and protocols that have been used to calibrate material model parameters and discuss artifacts that might falsify the measured properties. The aim of this work is to provide standardized procedures to reliably quantify the mechanical properties of brain tissue and to more accurately calibrate appropriate constitutive models for computational simulations of brain development, injury and disease. Computational models can not only be used to predictively understand brain tissue behavior, but can also serve as valuable tools to assist diagnosis and treatment of diseases or to plan neurosurgical procedures. © 2022 The Authors. Current Protocols published by Wiley Periodicals LLC.
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Affiliation(s)
- Jessica Faber
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Institute of Applied Mechanics, Egerlandstraße 5, 91058 Erlangen, Germany
| | - Jan Hinrichsen
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Institute of Applied Mechanics, Egerlandstraße 5, 91058 Erlangen, Germany
| | - Alexander Greiner
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Institute of Applied Mechanics, Egerlandstraße 5, 91058 Erlangen, Germany
| | - Nina Reiter
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Institute of Applied Mechanics, Egerlandstraße 5, 91058 Erlangen, Germany
| | - Silvia Budday
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Institute of Applied Mechanics, Egerlandstraße 5, 91058 Erlangen, Germany
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11
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Zhao H, Liu S, Wei Y, Yue Y, Gao M, Li Y, Zeng X, Deng X, Kotov NA, Guo L, Jiang L. Multiscale engineered artificial tooth enamel. Science 2022; 375:551-556. [PMID: 35113708 DOI: 10.1126/science.abj3343] [Citation(s) in RCA: 82] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Tooth enamel, renowned for its high stiffness, hardness, and viscoelasticity, is an ideal model for designing biomimetic materials, but accurate replication of complex hierarchical organization of high-performance biomaterials in scalable abiological composites is challenging. We engineered an enamel analog with the essential hierarchical structure at multiple scales through assembly of amorphous intergranular phase (AIP)-coated hydroxyapatite nanowires intertwined with polyvinyl alcohol. The nanocomposite simultaneously exhibited high stiffness, hardness, strength, viscoelasticity, and toughness, exceeding the properties of enamel and previously manufactured bulk enamel-inspired materials. The presence of AIP, polymer confinement, and strong interfacial adhesion are all needed for high mechanical performance. This multiscale design is suitable for scalable production of high-performance materials.
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Affiliation(s)
- Hewei Zhao
- School of Chemistry, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing 100191, China
| | - Shaojia Liu
- School of Chemistry, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing 100191, China
| | - Yan Wei
- Department of Geriatric Dentistry, NMPA Key Laboratory for Dental Materials, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing Laboratory of Biomedical Materials, Peking University School and Hospital of Stomatology, Beijing 100081, China
| | - Yonghai Yue
- School of Chemistry, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing 100191, China
| | - Mingrui Gao
- School of Chemistry, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing 100191, China
| | - Yangbei Li
- School of Chemistry, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing 100191, China
| | - Xiaolong Zeng
- School of Chemistry, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing 100191, China
| | - Xuliang Deng
- Department of Geriatric Dentistry, NMPA Key Laboratory for Dental Materials, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing Laboratory of Biomedical Materials, Peking University School and Hospital of Stomatology, Beijing 100081, China
| | - Nicholas A Kotov
- Department of Chemical Engineering, Department of Materials Science, Biointerface Institute, University of Michigan, Ann Arbor, MI 48109, USA.,Michigan Institute of Translational Nanotechnology (MITRAN), Ypsilanti, MI 48198, USA
| | - Lin Guo
- School of Chemistry, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing 100191, China
| | - Lei Jiang
- School of Chemistry, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing 100191, China.,CAS Key Laboratory of Bio-Inspired Materials and Interfacial Science, CAS Center for Excellence in Nanoscience, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China
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Klarić Sever E, Tarle A, Vukelja J, Soče M, Grego T. Direct Induced Effects of Standard and Modified Radiotherapy Protocol on Surface Structure of Hard Dental Tissue. Acta Stomatol Croat 2022; 55:334-345. [PMID: 35001929 PMCID: PMC8734449 DOI: 10.15644/asc55/4/1] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Accepted: 10/20/2021] [Indexed: 12/24/2022] Open
Abstract
Introduction Radiotherapy is used to treat neo plasmatic lesions and the common side effects of this process are pain, swelling and sensitivity of mucous membranes in domain of radiation, reduced salivation, caries, and periodontal disease and, in total, low life quality. The purpose of this research was to estimate the outcome of direct irradiation on physical and surface characteristics of hard dental tissues. Materials and methods Twenty, caries free third molars were involved in the research. Prior to different submission protocols, tooth halves were randomly assigned to subject and control groups by using a draw method. The first group (n=20) was submitted to conventional irradiation protocol (2 Gy for 35 days), second group (n=20) was submitted to one powerful, exploratory dose of 70 Gy. Each sample served as its own control. Radiation was performed with a linear accelerator radiotherapy unit. The surface microhardness and roughness were measured at the beginning (initially), and upon completion of irradiation procedure. The average change in microhardness and roughness after different treatments was compared by t-test for independent samples. Normality was tested by the Shapiro-Wilk test. Results Significant differences were found after the standard radiation protocol and the exploratory dose of 70 Gy, with decreased mean microhardness and increased mean roughness (p<0.001) of both hard dental tissues. Enamel and dentin surface microhardness and roughness did not vary notably with regards to different irradiation protocols. Conclusion Head and neck conventional irradiation protocol leads to possible breakdown of enamel and dentin with reduced microhardness and increased surface roughness regardless of used irradiation protocol.
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Affiliation(s)
- Eva Klarić Sever
- Department of Endodontics and Restorative Dental Medicine, School of Dental Medicine Zagreb
| | | | - Josipa Vukelja
- PhD student, School of Dental Medicine, University of Zagreb, Croatia
| | - Majana Soče
- Department of Oncology, Radiotherapy Unit, University Hospital Centre Zagreb, Zagreb
| | - Timor Grego
- Department of Oncology, Radiotherapy Unit, University Hospital Centre Zagreb, Zagreb
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Tritschler U, Delgado López JM, Umbach TR, Van Driessche AES, Schlaad H, Cölfen H, Kellermeier M. Oriented attachment and aggregation as a viable pathway to self-assembled organic/inorganic hybrid materials. CrystEngComm 2022. [DOI: 10.1039/d2ce00447j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The intrinsic particle-based mechanisms of calcium sulfate crystallisation are exploited to incorporate specific organic polymers in the emerging mineral phase and thus obtain biomimetic organic/inorganic hybrid structures via self-organisation.
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Affiliation(s)
- Ulrich Tritschler
- Physical Chemistry, University of Konstanz, Universitätsstrasse 10, D-78457 Konstanz, Germany
- Dispersions & Resins, BASF SE, Carl-Bosch-Strasse 38, D-67056 Ludwigshafen, Germany
| | | | - Tobias R. Umbach
- Material Science, BASF SE, Carl-Bosch-Strasse 38, D-67056 Ludwigshafen, Germany
| | | | - Helmut Schlaad
- Institute of Chemistry, University of Potsdam, Karl-Liebknecht-Strasse 24-25, D-14476 Potsdam, Germany
| | - Helmut Cölfen
- Physical Chemistry, University of Konstanz, Universitätsstrasse 10, D-78457 Konstanz, Germany
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14
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Klarić Sever E, Tarle A, Soče M, Grego T. Direct Radiotherapy-Induced Effects on Dental Hard Tissue in Combination With Bleaching Procedure. FRONTIERS IN DENTAL MEDICINE 2021. [DOI: 10.3389/fdmed.2021.714400] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/09/2022] Open
Abstract
Introduction: The aim of this study was to evaluate the effects of radiation and tooth bleaching on the physical and morphological properties of enamel and dentin on permanent teeth.Materials and Methods: Eighty fresh, non-carious third molars were used in this study. Before cutting the crown in half, the teeth samples were randomly allocated to treatment and control groups by using a lottery method. The first group (n = 20) underwent standard radiation protocol (2 Gy/fraction/day, 5 days/week) with bleaching treatment afterward using 16% carbamide peroxide gel, the second group (n = 20) underwent standard radiation protocol with afterward bleaching treatment using 38% hydrogen peroxide, the third group (n = 20) underwent a short, one strong, experimental dose of 70 Gy with afterward bleaching treatment using 16% carbamide peroxide gel, and the fourth group (n = 20) underwent one strong, experimental dose of 70 Gy with afterward bleaching treatment using 38% hydrogen peroxide gel. Groups 5–8 (n = 20) served as control as they underwent only bleaching treatment. Vickers microhardness and surface roughness were performed before (initial) and after irradiation and before bleaching or after only bleaching. The effects of irradiation and bleaching on microhardness (or roughness) of enamel and dentin were analyzed in the repeated-measures ANOVA model.Results: Enamel microhardness after experimental single 70-Gy irradiation or after standard radiation protocol and bleaching with 16 or 38% gel was not statistically significant from microhardness in the control group (p > 0.05). There was a statistically significantly greater reduction in the average microhardness of enamel and dentin during bleaching with 38% gel compared to 16% for both radiation protocols (p < 0.001). After experimental 70-Gy irradiation and bleaching, a 16% statistically significant increase in surface roughness was found for enamel (p = 0.006) and dentin (p = 0.018), while this was not recorded for 38% gel. There was a statistically significantly greater increase in the average roughness of enamel and dentin during bleaching with 38% gel compared to 16% (p < 0.001) for both radiation protocols.Conclusions: Directly induced radiation leads to potential damage of hard dental tissues, which can be further damaged by additional bleaching. If teeth whitening is necessary after irradiation, it is suggested to use lower concentrations of whitening gels.
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15
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Nedelkovski V, Andriotis OG, Wieland K, Gasser C, Steiger-Thirsfeld A, Bernardi J, Lendl B, Pretterklieber ML, Thurner PJ. Microbeam bending of hydrated human cortical bone lamellae from the central region of the body of femur shows viscoelastic behaviour. J Mech Behav Biomed Mater 2021; 125:104815. [PMID: 34678618 DOI: 10.1016/j.jmbbm.2021.104815] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 04/30/2021] [Accepted: 09/03/2021] [Indexed: 12/27/2022]
Abstract
Bone is a biological tissue with unique mechanical properties, owing to a complex hierarchical structure ranging from the nanoscale up to the macroscale. To better understand bone mechanics, investigation of mechanical properties of all structural elements at every hierarchical level and how they interact is necessary. Testing of bone structures at the lower microscale, e.g. bone lamellae, has been least performed and remains a challenge. Focused ion beam (FIB) milling is an attractive technique for machining microscopic samples from bone material and performing mechanical testing at the microscale using atomic force microscopy (AFM) and nanoindentation setups. So far, reported studies at this length scale have been performed on bone samples of animal origin, mostly in a dehydrated state, except for one study. Here we present an AFM-based microbeam bending method for performing bending measurements in both dehydrated and rehydrated conditions at the microscale. Single lamella bone microbeams of four human donors, aged 65-94 yrs, were machined via FIB and tested both in air and fully submerged in Hank's Balanced Salt Solution (HBSS) to investigate the effect of (de)hydration and to a certain extent, of age, on bone mechanics. Bending moduli were found to reduce up to 5 times after 2 h of rehydration and no trend of change in bending moduli with respect to age could be observed. Mechanical behavior changed from almost purely elastic to viscoelastic upon rehydration and a trend of lower dissipated energy in samples from older donors could be observed in the rehydrated state. These results confirm directly the importance of water for the mechanical properties of bone tissue at the microscale. Moreover, the trend of lowered capability of energy dissipation in older donors may contribute to a decrease of fracture toughness and thus an increase in bone fragility with age.
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Affiliation(s)
- Vedran Nedelkovski
- Institute of Lightweight Design and Structural Biomechanics, TU Wien, 1060, Vienna, Austria
| | - Orestis G Andriotis
- Institute of Lightweight Design and Structural Biomechanics, TU Wien, 1060, Vienna, Austria
| | - Karin Wieland
- Institute of Chemical Technologies and Analytics, TU Wien, 1060, Vienna, Austria
| | - Christoph Gasser
- Institute of Chemical Technologies and Analytics, TU Wien, 1060, Vienna, Austria
| | | | - Johannes Bernardi
- University Service Center for Transmission Electron Microscopy, TU Wien, 1040, Vienna, Austria
| | - Bernhard Lendl
- Institute of Chemical Technologies and Analytics, TU Wien, 1060, Vienna, Austria
| | - Michael L Pretterklieber
- Center for Anatomy and Cell Biology, Division of Anatomy, Medical University of Vienna, 1090, Vienna, Austria; Division of Macroscopic and Clinical Anatomy, Medical University Graz, 8010, Graz, Austria
| | - Philipp J Thurner
- Institute of Lightweight Design and Structural Biomechanics, TU Wien, 1060, Vienna, Austria.
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16
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Vahidi G, Rux C, Sherk VD, Heveran CM. Lacunar-canalicular bone remodeling: Impacts on bone quality and tools for assessment. Bone 2021; 143:115663. [PMID: 32987198 PMCID: PMC7769905 DOI: 10.1016/j.bone.2020.115663] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 09/23/2020] [Accepted: 09/23/2020] [Indexed: 01/06/2023]
Abstract
Osteocytes can resorb as well as replace bone adjacent to the expansive lacunar-canalicular system (LCS). Suppressed LCS remodeling decreases bone fracture toughness, but it is unclear how altered LCS remodeling impacts bone quality. The first goal of this review is to assess how LCS remodeling impacts LCS morphology as well as the composition and mechanical properties of surrounding bone tissue. The second goal is to compare tools available for the assessment of bone quality at length-scales that are physiologically-relevant to LCS remodeling. We find that changes to LCS morphology occur in response to a variety of physiological conditions and diseases and can be classified in two general phenotypes. In the 'aging phenotype', seen in aging and in some disuse models, the LCS is truncated and osteocytes apoptosis is increased. In the 'osteocytic osteolysis' phenotype, which is adaptive in some physiological settings and possibly maladaptive in others, the LCS enlarges and osteocytes generally maintain viability. Bone composition and mechanical properties vary near the osteocyte and change with at least some conditions that alter LCS morphology. However, few studies have evaluated bone composition and mechanical properties close to the LCS and so the impacts of LCS remodeling phenotypes on bone tissue quality are still undetermined. We summarize the current understanding of how LCS remodeling impacts LCS morphology, tissue-scale bone composition and mechanical properties, and whole-bone material properties. Tools are compared for assessing tissue-scale bone properties, as well as the resolution, advantages, and limitations of these techniques.
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Affiliation(s)
- G Vahidi
- Department of Mechanical & Industrial Engineering, Montana State University, United States of America
| | - C Rux
- Department of Mechanical & Industrial Engineering, Montana State University, United States of America
| | - V D Sherk
- Department of Orthopedics, University of Colorado Anschutz School of Medicine, United States of America
| | - C M Heveran
- Department of Mechanical & Industrial Engineering, Montana State University, United States of America.
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17
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Casari D, Michler J, Zysset P, Schwiedrzik J. Microtensile properties and failure mechanisms of cortical bone at the lamellar level. Acta Biomater 2021; 120:135-145. [PMID: 32428682 DOI: 10.1016/j.actbio.2020.04.030] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 04/09/2020] [Accepted: 04/16/2020] [Indexed: 12/15/2022]
Abstract
Bone features a remarkable combination of toughness and strength which originates from its complex hierarchical structure and motivates its investigation on multiple length scales. Here, in situ microtensile experiments were performed on dry ovine osteonal bone for the first time at the length scale of a single lamella. The micromechanical response was brittle and revealed larger ultimate tensile strength compared to the macroscale (factor of 2.3). Ultimate tensile strength for axial and transverse specimens was 0.35 ± 0.05 GPa and 0.13 ± 0.02 GPa, respectively. A significantly greater strength anisotropy relative to compression was observed (axial to transverse strength ratio of 2.7:1 for tension, 1.3:1 for compression). Fracture surface and transmission electron microscopic analysis suggested that this may be rationalized by a change in failure mode from fibril-matrix interfacial shearing for axial specimens to fibril-matrix debonding in the transverse direction. An improved version of the classic Hashin's composite failure model was applied to describe lamellar bone strength as a function of fibril orientation. Together with our experimental observations, the model suggests that cortical bone strength at the lamellar level is remarkably tolerant to variations of fibrils orientation of about ±30°. This study highlights the importance of investigating bone's hierarchical organization at several length scales for gaining a deeper understanding of its macroscopic fracture behavior. STATEMENT OF SIGNIFICANCE: Understanding bone deformation and failure behavior at different length scales of its hierarchical structure is fundamental for the improvement of bone fracture prevention, as well as for the development of multifunctional bio-inspired materials combining toughness and strength. The experiments reported in this study shed light on the microtensile properties of dry primary osteonal bone and establish a baseline from which to start further investigations in more physiological conditions. Microtensile specimens were stronger than their macroscopic counterparts by a factor of 2.3. Lamellar bone strength seems remarkably tolerant to variations of the sub-lamellar fibril orientation with respect to the loading direction (±30°). This study underlines the importance of studying bone on all length scales for improving our understanding of bone's macroscopic mechanical response.
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18
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Shipov A, Zaslansky P, Riesemeier H, Segev G, Atkins A, Kalish-Achrai N, Weiner S, Shahar R. The influence of estrogen deficiency on the structural and mechanical properties of rat cortical bone. PeerJ 2021; 9:e10213. [PMID: 33520431 PMCID: PMC7811283 DOI: 10.7717/peerj.10213] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 09/28/2020] [Indexed: 11/20/2022] Open
Abstract
Background Post-menopausal osteoporosis is a common health problem worldwide, most commonly caused by estrogen deficiency. Most of the information regarding the skeletal effects of this disease relates to trabecular bone, while cortical bone is less studied. The purpose of this study was to evaluate the influence of estrogen deficiency on the structure and mechanical properties of cortical bone. Methods Eight ovariectomized (OVH) and eight intact (control) Sprague Dawley rats were used.Structural features of femoral cortical bone were studied by light microscopy, scanning electron microscopy and synchrotron-based microcomputer-tomography and their mechanical properties determined by nano-indentation. Results Cortical bone of both study groups contains two distinct regions: organized circumferential lamellae and disordered bone with highly mineralized cartilaginous islands. Lacunar volume was lower in the OVH group both in the lamellar and disorganized regions (182 ± 75 µm3 vs 232 ± 106 µm3, P < 0.001 and 195 ± 86 µm3 vs. 247 ± 106 µm3, P < 0.001, respectively). Lacunar density was also lower in both bone regions of the OVH group (40 ± 18 ×103 lacunae/mm3 vs. 47 ± 9×103 lacunae/mm3 in the lamellar region, P = 0.003 and 63 ± 18×103lacunae/mm3 vs. 75 ± 13×103 lacunae/mm3 in the disorganized region, P < 0.001). Vascular canal volume was lower in the disorganized region of the bone in the OVH group compared to the same region in the control group (P < 0.001). Indentation moduli were not different between the study groups in both bone regions. Discussion Changes to cortical bone associated with estrogen deficiency in rats require high-resolution methods for detection. Caution is required in the application of these results to humans due to major structural differences between human and rat bone.
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Affiliation(s)
- Anna Shipov
- Koret School of Veterinary Medicine, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Paul Zaslansky
- Department for Operative and Preventive Dentistry. Centrum für Zahn-, Mund- und Kieferheilkunde, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | | | - Gilad Segev
- Koret School of Veterinary Medicine, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Ayelet Atkins
- Department of Chemistry and Bar Ilan Institute of Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, Ramat Gan, Israel
| | - Noga Kalish-Achrai
- Koret School of Veterinary Medicine, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Stephen Weiner
- Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Ron Shahar
- Koret School of Veterinary Medicine, The Hebrew University of Jerusalem, Rehovot, Israel
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19
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Duruk G, Acar B, Temelli Ö. Effect of different doses of radiation on morphogical, mechanical and chemical properties of primary and permanent teeth-an in vitro study. BMC Oral Health 2020; 20:242. [PMID: 32873280 PMCID: PMC7465328 DOI: 10.1186/s12903-020-01222-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 08/16/2020] [Indexed: 11/29/2022] Open
Abstract
Background Radiotherapy, applied to the head and neck region, can cause radiation side effects such as reduction of saliva and radiation caries. The aim of this study was to perform an in vitro assessment of the effects of radiation therapy on the morphological, mechanical, and chemical properties of primary and permanent teeth. Methods One hundred four extracted human teeth (52 impacted wisdom teeth, 52 primary molar teeth) were used. The teeth were divided into two parts in the mesiodistal direction. Of the 98 teeth, the vestibular sections were used for the vickers analysis and lingual sections were used for the Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES) analysis. The teeth in the experimental group were fixed to wax models. Each model had an equal number of teeth (n = 7). The doses were applied to the teeth for 6 weeks; 5 week days and 2Gy daily. After the radiotherapy was conducted weekly, a wax model was taken from radiation reception. Along with the elemental contents (Na, K, Mg, P, and Ca) of the teeth, enamel and dentin microhardness was evaluated, and SEM analyzes were performed on 6 teeth. Results Radiation caused a decrease in microhardness of enamel and dentin (p < 0.05). In the elemental analysis by ICP-OES, it was observed that there were decreases in all elements after 60Gy compared to the control group (p < 0.05). In the experimental groups, amorphous structures were encountered in SEM images. Conclusions Radiation has negative effects on the teeth structure and additional studies are needed in this regard. This study indicates that radiotherapy patients are at a higher risk for dental caries.
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Affiliation(s)
- Gülsüm Duruk
- Department of Pediatric Dentistry, Faculty of Dentistry, Inonu University, Malatya, Turkey.
| | - Burçin Acar
- Department of Pediatric Dentistry, Faculty of Dentistry, Inonu University, Malatya, Turkey
| | - Öztun Temelli
- Department of Radiation Oncology, Faculty of Medicine, Inonu University, Malatya, Turkey
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Nedelkovski V, Hahn R, Mayrhofer PH, Steiger-Thirsfeld A, Bernardi J, Thurner PJ. Influence of experimental constraints on micromechanical assessment of micromachined hard-tissue samples. J Mech Behav Biomed Mater 2020; 106:103741. [PMID: 32250952 DOI: 10.1016/j.jmbbm.2020.103741] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 02/14/2020] [Accepted: 03/10/2020] [Indexed: 11/26/2022]
Abstract
Continuing technological advancement of mechanical characterization at the microscale has enabled the isolation of micron-sized specimens and their direct mechanical characterization. Such techniques, initially developed for engineering materials and MEMS, can also be applied on hard biological materials. Bone is a material with a complex hierarchical structure ranging from the macro- all the way down to the nanoscale. To fully understand bone tissue mechanics, knowledge of the mechanics of all structural elements i.e. at every length scale is necessary. Particularly, the mechanical properties of microstructural elements, such as bone lamellae are still largely unknown. In the last decade, testing protocols have been devised to close this gap including bending and compression of micrometer-sized bone specimens. However, the precision and accuracy of results obtained have not been discussed. In this study, we aim to do exactly this: we validate microbeam bending by testing silicon microbeams with known mechanical constants, and evaluate the precision and sources of errors in both microbeam bending and micropillar compression by means of finite element (FE) modeling. Bending of Si-microbeams reproduced the expected value for the bending modulus within 17% accuracy, although the effect of geometrical uncertainties was estimated to result in relative errors of up to 50%. The deformation of constraining bulk material had a smaller influence, with relative errors of 11%, for microbeam bending and 25% for micropillar compression. For the latter this error could be sufficiently eliminated by the Sneddon correction. The tapering of micropillars had a negligible effect on overall apparent stiffness, but induced inhomogeneous stress state within micropillars may lead to superposed structural deformation mechanisms and be responsible for failure patterns observed in past studies.
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Affiliation(s)
- Vedran Nedelkovski
- Institute of Lightweight Design and Structural Biomechanics, TU Wien, 1060, Vienna, Austria
| | - Rainer Hahn
- Institute of Materials Science and Technology, TU Wien, 1060, Vienna, Austria
| | - Paul H Mayrhofer
- Institute of Materials Science and Technology, TU Wien, 1060, Vienna, Austria
| | | | - Johannes Bernardi
- University Service Center for Transmission Electron Microscopy, TU Wien, 1040, Vienna, Austria
| | - Philipp J Thurner
- Institute of Lightweight Design and Structural Biomechanics, TU Wien, 1060, Vienna, Austria.
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Grover K, Hu M, Lin L, Muir J, Qin YX. Functional disuse initiates medullary endosteal micro-architectural impairment in cortical bone characterized by nanoindentation. J Bone Miner Metab 2019; 37:1048-1057. [PMID: 31292723 DOI: 10.1007/s00774-019-01011-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 05/16/2019] [Indexed: 01/22/2023]
Abstract
In this study, we evaluated the effect of functional disuse-induced bone remodeling on its mechanical properties, individually at periosteum and medullary endosteum regions of the cortical bone. Left middle tibiae were obtained from 5-month-old female Sprague-Dawley rats for the baseline control as well as hindlimb suspended (disuse) groups. Micro-nano-mechanical elastic moduli (at lateral region) was evaluated along axial (Z), circumferential (C) and radial (R) orientations using nanoindentation. Results indicated an anisotropic microstructure with axial orientation having the highest and radial orientation with the lowest moduli at periosteum and medullary endosteum for both baseline control as well as disuse groups. Between the groups: at periosteum, an insignificant difference was evaluated for each of the orientations (p > 0.05) and at endosteum, a significant decrease of elastic moduli in the radial (p < 0.0001), circumferential (p < 0.001) and statistically insignificant difference in axial (p > 0.05) orientation. For the moduli ratios between groups: at periosteum, only significant difference in the Z/R (p < 0.05) anisotropy ratio, whereas at endosteum, a statistically significant difference in Z/C (p < 0.001), and Z/R (p < 0.001), as well as C/R (p < 0.05) anisotropy ratios, was evaluated. The results suggested initial bone remodeling impaired bone micro-architecture predominantly at the medullary endosteum with possible alterations in the geometric orientations of collagen and mineral phases inside the bone. The findings could be significant for studying the mechanotransduction pathways involved in maintaining the bone micro-architecture and possibly have high clinical significance for drug use against impairment from functional disuse.
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Affiliation(s)
- Kartikey Grover
- Department of Biomedical Engineering, SUNY Stony Brook University, 215 Bioengineering Building, Stony Brook, New York, 11794, USA
| | - Minyi Hu
- Department of Biomedical Engineering, SUNY Stony Brook University, 215 Bioengineering Building, Stony Brook, New York, 11794, USA
| | - Liangjun Lin
- Department of Biomedical Engineering, SUNY Stony Brook University, 215 Bioengineering Building, Stony Brook, New York, 11794, USA
| | - Jesse Muir
- Department of Biomedical Engineering, SUNY Stony Brook University, 215 Bioengineering Building, Stony Brook, New York, 11794, USA
| | - Yi-Xian Qin
- Department of Biomedical Engineering, SUNY Stony Brook University, 215 Bioengineering Building, Stony Brook, New York, 11794, USA.
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22
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Semaan M, Karam E, Baron C, Pithioux M. Estimation of the elastic modulus of child cortical bone specimens via microindentation. Connect Tissue Res 2019; 60:399-405. [PMID: 30646770 DOI: 10.1080/03008207.2019.1570170] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Purpose: Non-pathological child cortical bone (NPCCB) studies can provide clinicians with vital information and insights. However, assessing the anisotropic elastic properties of NPCCB remains a challenge for the biomechanical engineering community. For the first time, this paper provides elastic moduli values for NPCCB specimens in two perpendicular directions (longitudinal and transverse) and for two different structural components of bone tissue (osteon and interstitial lamellae). Materials and Methods: Microindentation is one of the reference methods used to measure bone stiffness. Here, 8 adult femurs (mean age 82 ± 8.9 years), 3 child femurs (mean age 13.3 ± 2.1 years), and 16 child fibulae (mean age 10.2 ± 3.9 years) were used to assess the elastic moduli of adult and child bones by microindentation. Results: For adult specimens, the mean moduli measured in this study are 18.1 (2.6) GPa for osteons, 21.3 (2.3) GPa for interstitial lamellae, and 13.8 (1.7) GPa in the transverse direction. For child femur specimens, the mean modulus is 14.1 (0.8) GPa for osteons, lower than that for interstitial lamellae: 15.5 (1.5) GPa. The mean modulus is 11.8 (0.7) GPa in the transverse direction. Child fibula specimens show a higher elastic modulus for interstitial lamellae 15.8 (1.5) than for osteons 13.5 (1.6), with 10.2 (1) GPa in the transverse direction. Conclusion: For the first time, NPCCB elastic modulus values are provided in longitudinal and transverse directions at the microscale level.
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Affiliation(s)
- Marie Semaan
- a Aix Marseille Univ, CNRS, ISM, Inst Movement Sci , Marseille , France.,b Faculty of Engineering , University of Balamand , Al Kurah , Lebanon.,c APHM, CNRS, ISM, Sainte-Marguerite Hospital, Institute for Locomotion, Department of Orthopaedics and Traumatology , , Marseille , France
| | - Elie Karam
- b Faculty of Engineering , University of Balamand , Al Kurah , Lebanon
| | - Cécile Baron
- a Aix Marseille Univ, CNRS, ISM, Inst Movement Sci , Marseille , France.,c APHM, CNRS, ISM, Sainte-Marguerite Hospital, Institute for Locomotion, Department of Orthopaedics and Traumatology , , Marseille , France
| | - Martine Pithioux
- a Aix Marseille Univ, CNRS, ISM, Inst Movement Sci , Marseille , France.,c APHM, CNRS, ISM, Sainte-Marguerite Hospital, Institute for Locomotion, Department of Orthopaedics and Traumatology , , Marseille , France
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23
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Soares PBF, Soares CJ, Limirio PHJO, de Jesus RNR, Dechichi P, Spin-Neto R, Zanetta-Barbosa D. Effect of ionizing radiation after-therapy interval on bone: histomorphometric and biomechanical characteristics. Clin Oral Investig 2018; 23:2785-2793. [PMID: 30368663 DOI: 10.1007/s00784-018-2724-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Accepted: 10/18/2018] [Indexed: 01/06/2023]
Abstract
OBJECTIVES This study aimed to evaluate the effects of radiotherapy on biomechanical, histomorphometric, and microstructural characteristics of bone, in diverse periods, compared with intact bone tissue. MATERIALS AND METHODS Eighteen adult male New Zealand rabbits were treated with a single radiation dose of 30 Gy. The animals were randomly divided into six groups: NoIr, control group, no radiation, and five irradiated groups sacrificed after 24 h (Ir24h), 7 (Ir7d), 14 (Ir14d), 21 (Ir21d), and 28 (Ir28d) days. After these periods, the animals were sacrificed and their tibias (n = 6) evaluated using three-point bending test to calculate the ultimate force, work to failure, and bone stiffness. Dynamic indentation test was used to quantify Vickers hardness and elasticity modulus of bone tissue. Micro-CT was used to analyze the cortical volume (CtV), cortical thickness (CtTh), and porosity (Ct.Po). Histomorphometric assessment was based on the lacunarity of bone tissue. Data were analyzed using one-way ANOVA and Kruskal-Wallis tests followed by Tukey, Dunnet, and Dunn's post-tests (P < 0.05). RESULTS The ultimate force, work to failure, stiffness, elastic modulus, and Vickers hardness values of irradiated bone were significantly lower that non-irradiated bone. Irradiated bone showed significantly lower CtTh and CtV values and higher CtPo than non-irradiated bone. No significant difference was found for lacunarity between non-irradiated bone and irradiated bone. CONCLUSIONS Ionizing radiation decreases normal anisotropy on microarchitecture of cortical bone, and increases bone fragility compared with non-irradiated bone. Further, these changes were seen after longer periods (e.g., 14 and 21 days), and not immediately after radiation therapy. CLINICAL RELEVANCE The radiotherapy reduces bone mechanical properties and the normal structure of organic and inorganic bone matrix. For studying the protocols to protect the radiotherapy effect using rabbit model, the use of the sacrificing period between 14 and 21 days is recommended.
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Affiliation(s)
- Priscilla Barbosa Ferreira Soares
- Department of Periodontology and Implantology, School of Dentistry, Federal University of Uberlândia, Avenida Pará s/n°, Campus Umuarama, Bloco 4L, Bairro Umuarama, Uberlândia, Minas Gerais, 38400-902, Brazil.
| | - Carlos José Soares
- Department of Operative Dentistry and Dental Materials, School of Dentistry, Federal University of Uberlândia, Avenida Pará s/n°, Campus Umuarama, Bloco 4L, Bairro Umuarama, Uberlândia, Minas Gerais, 38400-902, Brazil
| | - Pedro Henrique Justino Oliveira Limirio
- Department of Periodontology and Implantology, School of Dentistry, Federal University of Uberlândia, Avenida Pará s/n°, Campus Umuarama, Bloco 4L, Bairro Umuarama, Uberlândia, Minas Gerais, 38400-902, Brazil
| | - Rainde Naiara Rezende de Jesus
- Department of Oral and Maxillofacial Surgery, School of Dentistry, Federal University of Uberlândia, Avenida Pará s/n°, Campus Umuarama, Bloco 4T, Bairro Umuarama, Uberlândia, Minas Gerais, 38400-902, Brazil
| | - Paula Dechichi
- Institute of Biomedical Sciences, Federal University of Uberlândia, Avenida Pará 1720, Campus Umuarama, Bloco 2B, Bairro Umuarama, Uberlândia, Minas Gerais, 38400-902, Brazil
| | - Rubens Spin-Neto
- Department of Dentistry and Oral Health, Department of Oral Radiology, Aarhus University, Vennelyst Boulevard 9, Building 1613, 130, 8000, Aarhus C, Denmark
| | - Darceny Zanetta-Barbosa
- Department of Oral and Maxillofacial Surgery, School of Dentistry, Federal University of Uberlândia, Avenida Pará s/n°, Campus Umuarama, Bloco 4T, Bairro Umuarama, Uberlândia, Minas Gerais, 38400-902, Brazil
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Wu D, Isaksson P, Ferguson SJ, Persson C. Young's modulus of trabecular bone at the tissue level: A review. Acta Biomater 2018; 78:1-12. [PMID: 30081232 DOI: 10.1016/j.actbio.2018.08.001] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Revised: 06/30/2018] [Accepted: 08/02/2018] [Indexed: 01/06/2023]
Abstract
The tissue-level Young's modulus of trabecular bone is important for detailed mechanical analysis of bone and bone-implant mechanical interactions. However, the heterogeneity and small size of the trabecular struts complicate an accurate determination. Methods such as micro-mechanical testing of single trabeculae, ultrasonic testing, and nanoindentation have been used to estimate the trabecular Young's modulus. This review summarizes and classifies the trabecular Young's moduli reported in the literature. Information on species, anatomic site, and test condition of the samples has also been gathered. Advantages and disadvantages of the different methods together with recent developments are discussed, followed by some suggestions for potential improvement for future work. In summary, this review provides a thorough introduction to the approaches used for determining trabecular Young's modulus, highlights important considerations when applying these methods and summarizes the reported Young's modulus for follow-up studies on trabecular properties. STATEMENT OF SIGNIFICANCE The spongy trabecular bone provides mechanical support while maintaining a low weight. A correct measure of its mechanical properties at the tissue level, i.e. at a single-trabecula level, is crucial for analysis of interactions between bone and implants, necessary for understanding e.g. bone healing mechanisms. In this study, we comprehensively summarize the Young's moduli of trabecular bone estimated by currently available methods, and report their dependency on different factors. The critical review of different methods with recent updates is intended to inspire improvements in estimating trabecular Young's modulus. It is strongly suggested to report detailed information on the tested bone to enable statistical analysis in the future.
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Sharma D, Larriera AI, Palacio-Mancheno PE, Gatti V, Fritton JC, Bromage TG, Cardoso L, Doty SB, Fritton SP. The effects of estrogen deficiency on cortical bone microporosity and mineralization. Bone 2018; 110:1-10. [PMID: 29357314 PMCID: PMC6377161 DOI: 10.1016/j.bone.2018.01.019] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 01/09/2018] [Accepted: 01/15/2018] [Indexed: 12/22/2022]
Abstract
Recent studies have demonstrated matrix-mineral alterations in bone tissue surrounding osteocytes in estrogen-deficient animals. While cortical bone porosity has been shown to be a contributor to the mechanical properties of bone tissue, little analysis has been done to investigate the effects of estrogen deficiency on bone's microporosities, including the vascular and osteocyte lacunar porosities. In this study we examined alterations in cortical bone microporosity, mineralization, and cancellous bone architecture due to estrogen deficiency in the ovariectomized rat model of postmenopausal osteoporosis. Twenty-week-old female Sprague-Dawley rats were subjected to either ovariectomy or sham surgery. Six weeks post-surgery tibiae were analyzed using high-resolution micro-CT, backscattered electron imaging, nanoindentation, and dynamic histomorphometry. Estrogen deficiency caused an increase in cortical bone vascular porosity, with enlarged vascular pores and little change in tissue mineral density in the proximal tibial metaphysis. Measurements of cancellous architecture corresponded to previous studies reporting a decrease in bone volume fraction, an increase in trabecular separation, and a decrease in trabecular number in the proximal tibia due to estrogen deficiency. Nanoindentation results showed no differences in matrix stiffness in osteocyte-rich areas of the proximal tibia of estrogen-deficient rats, and bone labeling and backscattered electron imaging showed no significant changes in mineralization around the vascular pores. The findings demonstrate local surface alterations of vascular pores due to estrogen deficiency. An increase in cortical vascular porosity may diminish bone strength as well as alter bone mechanotransduction via interstitial fluid flow, both of which could contribute to bone fragility during postmenopausal osteoporosis.
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Affiliation(s)
- Divya Sharma
- Department of Biomedical Engineering, The City College of New York, New York, NY 10031, United States
| | - Adriana I Larriera
- Department of Biomedical Engineering, The City College of New York, New York, NY 10031, United States
| | - Paolo E Palacio-Mancheno
- Department of Biomedical Engineering, The City College of New York, New York, NY 10031, United States
| | - Vittorio Gatti
- Department of Biomedical Engineering, The City College of New York, New York, NY 10031, United States
| | - J Christopher Fritton
- Department of Orthopaedics, New Jersey Medical School, Rutgers University, Newark, NJ 07103, United States
| | - Timothy G Bromage
- Department of Biomaterials, New York University College of Dentistry, New York, NY 10010, United States
| | - Luis Cardoso
- Department of Biomedical Engineering, The City College of New York, New York, NY 10031, United States
| | - Stephen B Doty
- Research Division, Hospital for Special Surgery, New York, NY 10021, United States
| | - Susannah P Fritton
- Department of Biomedical Engineering, The City College of New York, New York, NY 10031, United States.
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26
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Deang JF, Persons AK, Oppedal AL, Rhee H, Moser RD, Horstemeyer MF. Structure, property, and function of sheepshead (Archosargus probatocephalus) teeth. Arch Oral Biol 2018; 89:1-8. [PMID: 29407634 DOI: 10.1016/j.archoralbio.2018.01.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 12/14/2017] [Accepted: 01/17/2018] [Indexed: 11/30/2022]
Abstract
OBJECTIVES This paper studies A. probatocephalus teeth and investigates the mechanical properties and chemical composition of the enameloid and dentin. DESIGN Nanoindentation tests with a max load of 1000 μN and X-ray Energy Dispersive Spectroscopy (EDS) were performed along the diameter of the polished sample. Microstructural analysis of the dentin tubules was performed from SEM images. RESULTS From nanoindentation testing, the dentin of the sheepshead teeth has a nanoindentation hardness of 0.89 ± 0.21 (mean ± S.D.) GPa and a reduced Young's modulus of 23.29 ± 5.30 GPa. The enameloid of A. probatocephalus has a hardness of 4.36 ± 0.44 GPa and a mean reduced Young's modulus of 98.14 ± 6.91 GPa. Additionally, nanoindentation tests showed that the enameloid's hardness and modulus increased closer to the surface of the tooth. X-ray Energy Dispersive Spectroscopy (EDS) data further suggests that the gradient may be a result of the wt% fluoride within the enameloid, where an increase in fluoride results in an increase in reduced Young's modulus and hardness. CONCLUSION The microstructural characterization of the number density and area of the dentin tubules were used to address the porosity effect in the dentin to achieve the experimentally validated microhardness. The mechanical properties of the sheepshead teeth were also compared with previous nanoindentation tests from other aquatic species. The sheepshead teeth exhibit a greater reduced Young's modulus and hardness compared to shark and piranha teeth.
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Affiliation(s)
- J F Deang
- Department of Mechanical Engineering, Mississippi State University, Mississippi State, MS 39762, USA; Center for Advanced Vehicular Systems, Mississippi State University, Mississippi State, MS 39762, USA.
| | - A K Persons
- Department of Mechanical Engineering, Mississippi State University, Mississippi State, MS 39762, USA; Center for Advanced Vehicular Systems, Mississippi State University, Mississippi State, MS 39762, USA
| | - A L Oppedal
- Center for Advanced Vehicular Systems, Mississippi State University, Mississippi State, MS 39762, USA
| | - H Rhee
- Department of Mechanical Engineering, Mississippi State University, Mississippi State, MS 39762, USA; Center for Advanced Vehicular Systems, Mississippi State University, Mississippi State, MS 39762, USA
| | - R D Moser
- US Army Engineer Research and Development Center, Geotechnical and Structures Laboratory, 3909 Halls Ferry Rd., Vicksburg, MS 39180, USA
| | - M F Horstemeyer
- Department of Mechanical Engineering, Mississippi State University, Mississippi State, MS 39762, USA; Center for Advanced Vehicular Systems, Mississippi State University, Mississippi State, MS 39762, USA
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Peters AE, Akhtar R, Comerford EJ, Bates KT. Tissue material properties and computational modelling of the human tibiofemoral joint: a critical review. PeerJ 2018; 6:e4298. [PMID: 29379690 PMCID: PMC5787350 DOI: 10.7717/peerj.4298] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 01/08/2018] [Indexed: 02/03/2023] Open
Abstract
Understanding how structural and functional alterations of individual tissues impact on whole-joint function is challenging, particularly in humans where direct invasive experimentation is difficult. Finite element (FE) computational models produce quantitative predictions of the mechanical and physiological behaviour of multiple tissues simultaneously, thereby providing a means to study changes that occur through healthy ageing and disease such as osteoarthritis (OA). As a result, significant research investment has been placed in developing such models of the human knee. Previous work has highlighted that model predictions are highly sensitive to the various inputs used to build them, particularly the mathematical definition of material properties of biological tissues. The goal of this systematic review is two-fold. First, we provide a comprehensive summation and evaluation of existing linear elastic material property data for human tibiofemoral joint tissues, tabulating numerical values as a reference resource for future studies. Second, we review efforts to model tibiofemoral joint mechanical behaviour through FE modelling with particular focus on how studies have sourced tissue material properties. The last decade has seen a renaissance in material testing fuelled by development of a variety of new engineering techniques that allow the mechanical behaviour of both soft and hard tissues to be characterised at a spectrum of scales from nano- to bulk tissue level. As a result, there now exists an extremely broad range of published values for human tibiofemoral joint tissues. However, our systematic review highlights gaps and ambiguities that mean quantitative understanding of how tissue material properties alter with age and OA is limited. It is therefore currently challenging to construct FE models of the knee that are truly representative of a specific age or disease-state. Consequently, recent tibiofemoral joint FE models have been highly generic in terms of material properties even relying on non-human data from multiple species. We highlight this by critically evaluating current ability to quantitatively compare and model (1) young and old and (2) healthy and OA human tibiofemoral joints. We suggest that future research into both healthy and diseased knee function will benefit greatly from a subject- or cohort-specific approach in which FE models are constructed using material properties, medical imagery and loading data from cohorts with consistent demographics and/or disease states.
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Affiliation(s)
- Abby E. Peters
- Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK
- Department of Mechanical, Materials and Aerospace Engineering, School of Engineering, University of Liverpool, Liverpool, UK
| | - Riaz Akhtar
- Department of Mechanical, Materials and Aerospace Engineering, School of Engineering, University of Liverpool, Liverpool, UK
| | - Eithne J. Comerford
- Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK
- Department of Mechanical, Materials and Aerospace Engineering, School of Engineering, University of Liverpool, Liverpool, UK
- Institute of Veterinary Science, University of Liverpool, Liverpool, UK
| | - Karl T. Bates
- Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK
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28
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Jenkins T, Katsamenis OL, Andriotis OG, Coutts LV, Carter B, Dunlop DG, Oreffo ROC, Cooper C, Harvey NC, Thurner PJ, The OStEO Group. The inferomedial femoral neck is compromised by age but not disease: Fracture toughness and the multifactorial mechanisms comprising reference point microindentation. J Mech Behav Biomed Mater 2017; 75:399-412. [PMID: 28803114 PMCID: PMC5619645 DOI: 10.1016/j.jmbbm.2017.06.036] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2017] [Revised: 06/26/2017] [Accepted: 06/28/2017] [Indexed: 12/19/2022]
Abstract
The influence of ageing on the fracture mechanics of cortical bone tissue is well documented, though little is known about if and how related material properties are further affected in two of the most prominent musculoskeletal diseases, osteoporosis and osteoarthritis (OA). The femoral neck, in close proximity to the most pertinent osteoporotic fracture site and near the hip joint affected by osteoarthritis, is a site of particular interest for investigation. We have recently shown that Reference Point micro-Indentation (RPI) detects differences between cortical bone from the femoral neck of healthy, osteoporotic fractured and osteoarthritic hip replacement patients. RPI is a new technique with potential for in vivo bone quality assessment. However, interpretation of RPI results is limited because the specific changes in bone properties with pathology are not well understood and, further, because it is not conclusive what properties are being assessed by RPI. Here, we investigate whether the differences previously detected between healthy and diseased cortical bone from the femoral neck might reflect changes in fracture toughness. Together with this, we investigate which additional properties are reflected in RPI measures. RPI (using the Biodent device) and fracture toughness tests were conducted on samples from the inferomedial neck of bone resected from donors with: OA (41 samples from 15 donors), osteoporosis (48 samples from 14 donors) and non age-matched cadaveric controls (37 samples from 10 donoros) with no history of bone disease. Further, a subset of indented samples were imaged using micro-computed tomography (3 osteoporotic and 4 control samples each from different donors) as well as fluorescence microscopy in combination with serial sectioning after basic fuchsin staining (7 osteoporotic and 5 control samples from 5 osteoporotic and 5 control donors). In this study, the bulk indentation and fracture resistance properties of the inferomedial femoral neck in osteoporotic fracture, severe OA and control bone were comparable (p > 0.05 for fracture properties and <10% difference for indentation) but fracture toughness reduced with advancing age (7.0% per decade, r = -0.36, p = 0.029). Further, RPI properties (in particular, the indentation distance increase, IDI) showed partial correlation with fracture toughness (r = -0.40, p = 0.023) or derived elastic modulus (r = -0.40, p = 0.023). Multimodal indent imaging revealed evidence of toughening mechanisms (i.e. crack deflection, bridging and microcracking), elastoplastic response (in terms of the non-conical imprint shape and presence of pile-up) and correlation of RPI with damage extent (up to r = 0.79, p = 0.034) and indent size (up to r = 0.82, p < 0.001). Therefore, crack resistance, deformation resistance and, additionally, micro-structure (porosity: r = 0.93, p = 0.002 as well as pore proximity: r = -0.55, p = 0.027 for correlation with IDI) are all contributory to RPI. Consequently, it becomes clear that RPI measures represent a multitude of properties, various aspects of bone quality, but are not necessarily strongly correlated to a single mechanical property. In addition, osteoporosis or osteoarthritis do not seem to further influence fracture toughness of the inferomedial femoral neck beyond natural ageing. Since bone is highly heterogeneous, whether this finding can be extended to the whole femoral neck or whether it also holds true for other femoral neck quadrants or other material properties remains to be shown.
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Affiliation(s)
- T Jenkins
- Bioengineering Science Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton, UK; Gait Laboratory, Queen Mary's Hospital, St George's University Hospitals NHS Foundation Trust, London, UK
| | - O L Katsamenis
- Bioengineering Science Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton, UK; µ-VIS X-ray Imaging Centre, Faculty of Engineering and the Environment, University of Southampton, SO17 1BJ Southampton, UK
| | - O G Andriotis
- Institute of Lightweight Design and Structural Biomechanics, Vienna University of Technology, Vienna, Austria
| | - L V Coutts
- Bioengineering Science Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton, UK
| | - B Carter
- Bioengineering Science Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton, UK
| | - D G Dunlop
- University Hospital Southampton NHS Foundation Trust, Southampton, UK
| | - R O C Oreffo
- Bone and Joint Research Group, Centre for Human Development, Stem Cells and Regeneration, Institute for Development Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
| | - C Cooper
- MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton, UK; NIHR Musculoskeletal Biomedical Research Unit, University of Oxford, Oxford, UK; NIHR Biomedical Research Centre, University of Southampton and University Hospital Southampton NHS Foundation Trust, Southampton, UK
| | - N C Harvey
- MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton, UK; NIHR Biomedical Research Centre, University of Southampton and University Hospital Southampton NHS Foundation Trust, Southampton, UK
| | - P J Thurner
- Bioengineering Science Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton, UK; Institute of Lightweight Design and Structural Biomechanics, Vienna University of Technology, Vienna, Austria.
| | - The OStEO Group
- University Hospital Southampton NHS Foundation Trust, Southampton, UK; MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton, UK; NIHR Musculoskeletal Biomedical Research Unit, University of Oxford, Oxford, UK; Portsmouth Hospitals NHS Trust, Portsmouth, UK; University College London, London, UK
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Arnold M, Zhao S, Ma S, Giuliani F, Hansen U, Cobb JP, Abel RL, Boughton O. Microindentation - a tool for measuring cortical bone stiffness? A systematic review. Bone Joint Res 2017; 6:542-549. [PMID: 28924020 PMCID: PMC5631024 DOI: 10.1302/2046-3758.69.bjr-2016-0317.r2] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 07/07/2017] [Indexed: 01/26/2023] Open
Abstract
Objectives Microindentation has the potential to measure the stiffness of an individual patient’s bone. Bone stiffness plays a crucial role in the press-fit stability of orthopaedic implants. Arming surgeons with accurate bone stiffness information may reduce surgical complications including periprosthetic fractures. The question addressed with this systematic review is whether microindentation can accurately measure cortical bone stiffness. Methods A systematic review of all English language articles using a keyword search was undertaken using Medline, Embase, PubMed, Scopus and Cochrane databases. Studies that only used nanoindentation, cancellous bone or animal tissue were excluded. Results A total of 1094 abstracts were retrieved and 32 papers were included in the analysis, 20 of which used reference point indentation, and 12 of which used traditional depth-sensing indentation. There are several factors that must be considered when using microindentation, such as tip size, depth and method of analysis. Only two studies validated microindentation against traditional mechanical testing techniques. Both studies used reference point indentation (RPI), with one showing that RPI parameters correlate well with mechanical testing, but the other suggested that they do not. Conclusion Microindentation has been used in various studies to assess bone stiffness, but only two studies with conflicting results compared microindentation with traditional mechanical testing techniques. Further research, including more studies comparing microindentation with other mechanical testing methods, is needed before microindentation can be used reliably to calculate cortical bone stiffness. Cite this article: M. Arnold, S. Zhao, S. Ma, F. Giuliani, U. Hansen, J. P. Cobb, R. L. Abel, O. Boughton. Microindentation – a tool for measuring cortical bone stiffness? A systematic review. Bone Joint Res 2017;6:542–549. DOI: 10.1302/2046-3758.69.BJR-2016-0317.R2.
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Affiliation(s)
- M Arnold
- Imperial College London, The MSk Lab, Imperial College London, Charing Cross Hospital, London W6 8RF, UK
| | - S Zhao
- Imperial College London, The MSk Lab, Imperial College London, Charing Cross Hospital, London W6 8RF, UK
| | - S Ma
- Imperial College London, The MSk Lab, Imperial College London, Charing Cross Hospital, London W6 8RF, UK and Department of Mechanical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - F Giuliani
- Imperial College London, Department of Mechanical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - U Hansen
- Imperial College London, Department of Mechanical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - J P Cobb
- Imperial College London, The MSk Lab, Imperial College London, Charing Cross Hospital, London W6 8RF, UK
| | - R L Abel
- Imperial College London, The MSk Lab, Imperial College London, Charing Cross Hospital, London W6 8RF, UK
| | - O Boughton
- Imperial College London, The MSk Lab, Imperial College London, Charing Cross Hospital, London W6 8RF, UK
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30
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Burke M, Atkins A, Kiss A, Akens M, Yee A, Whyne C. The impact of metastasis on the mineral phase of vertebral bone tissue. J Mech Behav Biomed Mater 2017; 69:75-84. [DOI: 10.1016/j.jmbbm.2016.12.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 12/12/2016] [Accepted: 12/20/2016] [Indexed: 12/22/2022]
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Vennin S, Desyatova A, Turner JA, Watson PA, Lappe JM, Recker RR, Akhter MP. Intrinsic material property differences in bone tissue from patients suffering low-trauma osteoporotic fractures, compared to matched non-fracturing women. Bone 2017; 97:233-242. [PMID: 28132909 PMCID: PMC5367951 DOI: 10.1016/j.bone.2017.01.031] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Revised: 01/10/2017] [Accepted: 01/24/2017] [Indexed: 10/20/2022]
Abstract
Osteoporotic (low-trauma) fractures are a significant public health problem. Over 50% of women over 50yrs. of age will suffer an osteoporotic fracture in their remaining lifetimes. While current therapies reduce skeletal fracture risk by maintaining or increasing bone density, additional information is needed that includes the intrinsic material strength properties of bone tissue to help develop better treatments, since measurements of bone density account for no more than ~50% of fracture risk. The hypothesis tested here is that postmenopausal women who have sustained osteoporotic fractures have reduced bone quality, as indicated with measures of intrinsic material properties compared to those who have not fractured. Transiliac biopsies (N=120) were collected from fracturing (N=60, Cases) and non-fracturing postmenopausal women (N=60, age- and BMD-matched Controls) to measure intrinsic material properties using the nano-indentation technique. Each biopsy specimen was embedded in epoxy resin and then ground, polished and used for the nano-indentation testing. After calibration, multiple indentations were made using quasi-static (hardness, modulus) and dynamic (storage and loss moduli) testing protocols. Multiple indentations allowed the median and variance to be computed for each type of measurement for each specimen. Cases were found to have significantly lower median values for cortical hardness and indentation modulus. In addition, cases showed significantly less within-specimen variability in cortical modulus, cortical hardness, cortical storage modulus and trabecular hardness, and more within-specimen variability in trabecular loss modulus. Multivariate modeling indicated the presence of significant independent mechanical effects of cortical loss modulus, along with variability of cortical storage modulus, cortical loss modulus, and trabecular hardness. These results suggest mechanical heterogeneity of bone tissue may contribute to fracture resistance. Although the magnitudes of differences in the intrinsic properties were not overwhelming, this is the first comprehensive study to investigate, and compare the intrinsic properties of bone tissue in fracturing and non-fracturing postmenopausal women.
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Affiliation(s)
- S Vennin
- University of Nebraska-Lincoln, NE, United States
| | - A Desyatova
- University of Nebraska-Lincoln, NE, United States
| | - J A Turner
- University of Nebraska-Lincoln, NE, United States
| | - P A Watson
- Osteoporosis Research Center, Creighton University, Omaha, NE, United States
| | - J M Lappe
- Osteoporosis Research Center, Creighton University, Omaha, NE, United States
| | - R R Recker
- Osteoporosis Research Center, Creighton University, Omaha, NE, United States
| | - M P Akhter
- Osteoporosis Research Center, Creighton University, Omaha, NE, United States.
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Atkins A, Milgram J, Weiner S, Shahar R. The response of anosteocytic bone to controlled loading. ACTA ACUST UNITED AC 2017; 218:3559-69. [PMID: 26582932 DOI: 10.1242/jeb.124073] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The bones of the skeleton of most advanced teleost fish do not contain osteocytes. Considering the pivotal role assigned to osteocytes in the process of modeling and remodeling (the adaptation of external and internal bone structure and morphology to external loads and the repair of areas with micro-damage accumulation, respectively) it is unclear how, and even whether, their skeleton can undergo modeling and remodeling. Here, we report on the results of a study of controlled loading of the anosteocytic opercula of tilapia (Oreochromis aureus). Using a variety of microscopy techniques we show that the bone of the anosteocytic tilapia actively adapts to applied loads, despite the complete absence of osteocytes. We show that in the directly loaded area, the response involves a combination of bone resorption and bone deposition; we interpret these results and the structure of the resultant bone tissue to mean that both modeling and remodeling are taking place in response to load. We further show that adjacent to the loaded area, new bone is deposited in an organized, layered manner, typical of a modeling process. The material stiffness of the newly deposited bone is higher than that of the bone which was present prior to loading. The absence of osteocytes requires another candidate cell for mechanosensing and coordinating the modeling process, with osteoblasts seeming the most likely candidates.
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Affiliation(s)
- Ayelet Atkins
- Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel
| | - Joshua Milgram
- Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel
| | - Steve Weiner
- Department of Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Ron Shahar
- Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel
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Abstract
Tissue-level mechanical properties characterize mechanical behavior independently of microscopic porosity. Specifically, quasi-static nanoindentation provides measurements of modulus (stiffness) and hardness (resistance to yielding) of tissue at the length scale of the lamella, while dynamic nanoindentation assesses time-dependent behavior in the form of storage modulus (stiffness), loss modulus (dampening), and loss factor (ratio of the two). While these properties are useful in establishing how a gene, signaling pathway, or disease of interest affects bone tissue, they generally do not vary with aging after skeletal maturation or with osteoporosis. Heterogeneity in tissue-level mechanical properties or in compositional properties may contribute to fracture risk, but a consensus on whether the contribution is negative or positive has not emerged. In vivo indentation of bone tissue is now possible, and the mechanical resistance to microindentation has the potential for improving fracture risk assessment, though determinants are currently unknown.
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Affiliation(s)
- Jeffry S Nyman
- Department of Orthopaedic Surgery and Rehabilitation, Vanderbilt University Medical Center, 1215 21st Ave. S., South Tower, Suite 4200, Nashville, TN, 37232, USA.
- Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, TN, 37212, USA.
- Center for Bone Biology, Vanderbilt University Medical Center, Nashville, TN, 37232, USA.
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, 37232, USA.
| | - Mathilde Granke
- Department of Orthopaedic Surgery and Rehabilitation, Vanderbilt University Medical Center, 1215 21st Ave. S., South Tower, Suite 4200, Nashville, TN, 37232, USA
- Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, TN, 37212, USA
- Center for Bone Biology, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Robert C Singleton
- Materials Science and Engineering Department, University of Tennessee, Knoxville, TN, 37996, USA
| | - George M Pharr
- Materials Science and Engineering Department, University of Tennessee, Knoxville, TN, 37996, USA
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
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Yu DG, Nie SB, Liu FX, Wu CL, Tian B, Wang WG, Wang XQ, Zhu ZA, Mao YQ. Dynamic Alterations in Microarchitecture, Mineralization and Mechanical Property of Subchondral Bone in Rat Medial Meniscal Tear Model of Osteoarthritis. Chin Med J (Engl) 2016; 128:2879-86. [PMID: 26521785 PMCID: PMC4756896 DOI: 10.4103/0366-6999.168045] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Background: The properties of subchondral bone influence the integrity of articular cartilage in the pathogenesis of osteoarthritis (OA). However, the characteristics of subchondral bone alterations remain unresolved. The present study aimed to observe the dynamic alterations in the microarchitecture, mineralization, and mechanical properties of subchondral bone during the progression of OA. Methods: A medial meniscal tear (MMT) operation was performed in 128 adult Sprague Dawley rats to induce OA. At 2, 4, 8, and 12 weeks following the MMT operation, cartilage degeneration was evaluated using toluidine blue O staining, whereas changes in the microarchitecture indices and tissue mineral density (TMD), mineral-to-collagen ratio, and intrinsic mechanical properties of subchondral bone plates (BPs) and trabecular bones (Tbs) were measured using micro-computed tomography scanning, confocal Raman microspectroscopy and nanoindentation testing, respectively. Results: Cartilage degeneration occurred and worsened progressively from 2 to 12 weeks after OA induction. Microarchitecture analysis revealed that the subchondral bone shifted from bone resorption early (reduced trabecular BV/TV, trabecular number, connectivity density and trabecular thickness [Tb.Th], and increased trabecular spacing (Tb.Sp) at 2 and 4 weeks) to bone accretion late (increased BV/TV, Tb.Th and thickness of subchondral bone plate, and reduced Tb.Sp at 8 and 12 weeks). The TMD of both the BP and Tb displayed no significant changes at 2 and 4 weeks but decreased at 8 and 12 weeks. The mineral-to-collagen ratio showed a significant decrease from 4 weeks for the Tb and from 8 weeks for the BP after OA induction. Both the elastic modulus and hardness of the Tb showed a significant decrease from 4 weeks after OA induction. The BP showed a significant decrease in its elastic modulus from 8 weeks and its hardness from 4 weeks. Conclusion: The microarchitecture, mineralization and mechanical properties of subchondral bone changed in a time-dependent manner as OA progressed.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Yuan-Qing Mao
- Shanghai Key Laboratory of Orthopedic Implants, Department of Orthopaedic Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, China
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CHITTENDEN MICHAEL, NAJAFI AHMADRAEISI, LI JUN, JASIUK IWONA. NANOINDENTATION AND ASH CONTENT STUDY OF AGE DEPENDENT CHANGES IN PORCINE CORTICAL BONE. J MECH MED BIOL 2015. [DOI: 10.1142/s0219519415500748] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Composition-structure-property relations of bone provide fundamental understanding of bone quality. The objective of this paper was to investigate age dependent changes in the composition, structure and mechanical properties of porcine femoral cortical bone at mid-diaphysis region from six age groups (1, 3.5, 6, 12, 30, 48 months). This study was motivated by the fact that limited data is available in the literature on young porcine cortical bone. Nanoindentation technique with Berkovich fluid cell tip was employed to measure the elastic modulus and hardness. Individual lamellae were indented in the longitudinal direction of bone in different microstructural components (osteonal, interstitial and plexiform bone). A grid of indentations was also made on one bone sample to obtain spatial variations in the elastic modulus and hardness. Ash and water content tests were performed to measure water, organic and mineral contents of bone as a function of age. Finally, high resolution micro-computed tomography was used to measure porosity and visualize three-dimensional void structures. We found that the elastic modulus and hardness of bone increased with age but at different rates in each microstructural component. The mineral content increased correspondingly with age while the porosity decreased. The obtained structure, composition, and mechanical properties data give new insights on the age related changes in young cortical bone and can serve as inputs for and validation of multiscale models of bone.
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Affiliation(s)
- MICHAEL CHITTENDEN
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, 1206 West Green Street, Urbana, IL 61801, USA
| | - AHMAD RAEISI NAJAFI
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, 1206 West Green Street, Urbana, IL 61801, USA
| | - JUN LI
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, 1206 West Green Street, Urbana, IL 61801, USA
| | - IWONA JASIUK
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, 1206 West Green Street, Urbana, IL 61801, USA
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Lambers FM, Bouman AR, Tkachenko EV, Keaveny TM, Hernandez CJ. The effects of tensile-compressive loading mode and microarchitecture on microdamage in human vertebral cancellous bone. J Biomech 2015; 47:3605-12. [PMID: 25458150 DOI: 10.1016/j.jbiomech.2014.10.011] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 09/16/2014] [Accepted: 10/05/2014] [Indexed: 11/26/2022]
Abstract
The amount of microdamage in bone tissue impairs mechanical performance and may act as a stimulus for bone remodeling. Here we determine how loading mode (tension vs. compression) and microstructure (trabecular microarchitecture, local trabecular thickness, and presence of resorption cavities) influence the number and volume of microdamage sites generated in cancellous bone following a single overload. Twenty paired cylindrical specimens of human vertebral cancellous bone from 10 donors (47–78 years) were mechanically loaded to apparent yield in either compression or tension, and imaged in three dimensions for microarchitecture and microdamage (voxel size 0.7×0.7×5.0 μm3). We found that the overall proportion of damaged tissue was greater (p=0.01) for apparent tension loading (3.9±2.4%, mean±SD) than for apparent compression loading (1.9±1.3%). Individual microdamage sites generated in tension were larger in volume (p<0.001) but not more numerous (p=0.64) than sites in compression. For both loading modes, the proportion of damaged tissue varied more across donors than with bone volume fraction, traditional measures of microarchitecture (trabecular thickness, trabecular separation, etc.), apparent Young׳s modulus, or strength. Microdamage tended to occur in regions of greater trabecular thickness but not near observable resorption cavities. Taken together, these findings indicate that, regardless of loading mode, accumulation of microdamage in cancellous bone after monotonic loading to yield is influenced by donor characteristics other than traditional measures of microarchitecture, suggesting a possible role for tissue material properties.
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Structural orientation dependent sub-lamellar bone mechanics. J Mech Behav Biomed Mater 2015; 52:63-71. [PMID: 25816782 DOI: 10.1016/j.jmbbm.2015.02.031] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Revised: 02/26/2015] [Accepted: 02/28/2015] [Indexed: 11/23/2022]
Abstract
The lamellar unit is a critical component in defining the overall mechanical properties of bone. In this paper, micro-beams of bone with dimensions comparable to the lamellar unit were fabricated using focused ion beam (FIB) microscopy and mechanically tested in bending to failure using atomic force microscopy (AFM). A variation in the mechanical properties, including elastic modulus, strength and work to fracture of the micro-beams was observed and related to the collagen fibril orientation inferred from back-scattered scanning electron microscopy (SEM) imaging. Established mechanical models were further applied to describe the relationship between collagen fibril orientation and mechanical behaviour of the lamellar unit. Our results highlight the ability to measure mechanical properties of discrete bone volumes directly and correlate with structural orientation of collagen fibrils.
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38
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Reed R, Xu C, Liu Y, Gorski JP, Wang Y, Walker MP. Radiotherapy effect on nano-mechanical properties and chemical composition of enamel and dentine. Arch Oral Biol 2015; 60:690-7. [PMID: 25766468 DOI: 10.1016/j.archoralbio.2015.02.020] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2014] [Revised: 12/19/2014] [Accepted: 02/20/2015] [Indexed: 02/01/2023]
Abstract
OBJECTIVE To understand radiotherapy-induced dental lesions characterized by enamel loss or delamination near the dentine-enamel junction (DEJ), this study evaluated enamel and dentine nano-mechanical properties and chemical composition before and after simulated oral cancer radiotherapy. DESIGN Sections from seven non-carious third molars were exposed to 2 Gy fractions, 5 days/week for 7 weeks for a total of 70 Gy. Nanoindentation was used to evaluate Young's modulus, while Raman microspectroscopy was used to measure protein/mineral ratios, carbonate/phosphate ratios, and phosphate peak width. All measures were completed prior to and following radiation at the same four buccal and lingual sites 500 and 30 μm from the DEJ in enamel and dentine (E-500, E-30, D-30 and D-500). RESULTS The elastic modulus of enamel and dentine was significantly increased (P ≤ 0.05) following radiation. Based on Raman spectroscopic analysis, there was a significant decrease in the protein to mineral ratio (2931/430 cm(-1)) following radiation at all sites tested except at D-500, while the carbonate to phosphate ratio (1070/960 cm(-1)) increased at E-30 and decreased at D-500. Finally, phosphate peak width as measured by FWHM at 960 cm(-1) significantly decreased at both D-30 and D-500 following radiation. CONCLUSIONS Simulated radiotherapy produced an increase in the stiffness of enamel and dentine near the DEJ. Increased stiffness is speculated to be the result of the radiation-induced decrease in the protein content, with the percent reduction much greater in the enamel sites. Such changes in mechanical properties and chemical composition could potentially contribute to DEJ biomechanical failure leading to enamel delamination that occurs post-radiotherapy. However, other analyses are required for a better understanding of radiotherapy-induced effects on tooth structure to improve preventive and restorative treatments for oral cancer patients.
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Affiliation(s)
- R Reed
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, MO, United States
| | - C Xu
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, MO, United States
| | - Y Liu
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, MO, United States
| | - J P Gorski
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, MO, United States; Center of Excellencein Musculoskeletal and Dental Tissues, University of Missouri-Kansas City, MO, United States
| | - Y Wang
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, MO, United States; Center of Excellencein Musculoskeletal and Dental Tissues, University of Missouri-Kansas City, MO, United States
| | - M P Walker
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, MO, United States; Center of Excellencein Musculoskeletal and Dental Tissues, University of Missouri-Kansas City, MO, United States.
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Tostes MA, Santos E, Camargo SA. Effect of resin infiltration on the nanomechanical properties of demineralized bovine enamel. Indian J Dent 2015; 5:116-22. [PMID: 25565739 PMCID: PMC4213871 DOI: 10.4103/0975-962x.140819] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Objective: The aim of the present study was to evaluate the efficacy of resin infiltration in preventing in vitro lesion progression. Materials and Methods: Buccal surfaces of bovine incisors were divided into mesial and distal regions and, at the center, nail varnish was applied (1.0 mm width) to protect the enamel surface against any further treatment. In order to create artificial enamel lesions in the unprotected areas, each specimen was soaked in a demineralizing solution. After that, specimens had two enamel lesions. One lesion in each sample was etched with 15% HCl for 120 s and infiltrated with a commercial infiltrating resin for 3 min, while the other lesion was not treated (control). Each specimen was cross-sectionally halved and randomly allocated to two groups: Group 1 was immediately processed and Group 2 was submitted to a new demineralization process. The samples were analyzed by means of cross-sectional hardness measurements using a nanoindenter equipment. Hardness data were statistically analyzed by non-parametric Kruskal-Wallis and MannWhitney tests (α = 0.05). Results: The findings showed statistical difference between treatments at the same analyzed distance range from the outer surface of the enamel (P < 0.05). Conclusion: The untreated lesion showed lower hardness values for distances near the outer surface of the enamel. The resin infiltration was efficient in preventing further in vitro demineralization of bovine enamel lesions.
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Affiliation(s)
- Mônica Almeida Tostes
- Department of Pediatric Dentistry, School of Dentistry, Fluminense Federal University, Niterói, RJ, Brazil
| | - Emanuel Santos
- Department of Metallurgical and Materials Engineering, COPPE, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Sérgio Alvaro Camargo
- Department of Metallurgical and Materials Engineering, COPPE, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
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Relationships between tissue composition and viscoelastic properties in human trabecular bone. J Biomech 2015; 48:269-75. [DOI: 10.1016/j.jbiomech.2014.11.034] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 11/21/2014] [Accepted: 11/24/2014] [Indexed: 01/22/2023]
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41
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Bianchi M, Boi M, Sartori M, Giavaresi G, Lopomo N, Fini M, Dediu A, Tampieri A, Marcacci M, Russo A. Nanomechanical mapping of bone tissue regenerated by magnetic scaffolds. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2015; 26:5363. [PMID: 25578711 DOI: 10.1007/s10856-014-5363-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Accepted: 08/06/2014] [Indexed: 06/04/2023]
Abstract
Nanoindentation can provide new insights on the maturity stage of regenerating bone. The aim of the present study was the evaluation of the nanomechanical properties of newly-formed bone tissue at 4 weeks from the implantation of permanent magnets and magnetic scaffolds in the trabecular bone of rabbit femoral condyles. Three different groups have been investigated: MAG-A (NdFeB magnet + apatite/collagen scaffold with magnetic nanoparticles directly nucleated on the collagen fibers during scaffold synthesis); MAG-B (NdFeB magnet + apatite/collagen scaffold later infiltrated with magnetic nanoparticles) and MAG (NdFeB magnet). The mechanical properties of different-maturity bone tissues, i.e. newly-formed immature, newly-formed mature and native trabecular bone have been evaluated for the three groups. Contingent correlations between elastic modulus and hardness of immature, mature and native bone have been examined and discussed, as well as the efficacy of the adopted regeneration method in terms of "mechanical gap" between newly-formed and native bone tissue. The results showed that MAG-B group provided regenerated bone tissue with mechanical properties closer to that of native bone compared to MAG-A or MAG groups after 4 weeks from implantation. Further, whereas the mechanical properties of newly-formed immature and mature bone were found to be fairly good correlated, no correlation was detected between immature or mature bone and native bone. The reported results evidence the efficacy of nanoindentation tests for the investigation of the maturity of newly-formed bone not accessible through conventional analyses.
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Affiliation(s)
- Michele Bianchi
- Laboratory of Nano-Biotechnologies (NaBi), Rizzoli Orthopaedic Institute, Via Gobetti 1/10, Bologna, 40136, Italy,
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Schwiedrzik J, Zysset P. Quantitative analysis of imprint shape and its relation to mechanical properties measured by microindentation in bone. J Biomech 2015; 48:210-6. [DOI: 10.1016/j.jbiomech.2014.12.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Revised: 11/11/2014] [Accepted: 12/01/2014] [Indexed: 12/01/2022]
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Importance of age on the dynamic mechanical behavior of intertubular and peritubular dentin. J Mech Behav Biomed Mater 2014; 42:229-42. [PMID: 25498296 DOI: 10.1016/j.jmbbm.2014.11.021] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Revised: 11/20/2014] [Accepted: 11/22/2014] [Indexed: 11/23/2022]
Abstract
An experimental evaluation of human coronal dentin was performed using nanoscopic dynamic mechanical analysis (nanoDMA). The primary objectives were to quantify any unique changes in mechanical behavior of intertubular and peritubular dentin with age, and to evaluate the microstructure and mechanical behavior of the mineral deposited within the lumens. Specimens of coronal dentin were evaluated by nanoDMA using single indents and in scanning mode via scanning probe microscopy. Results showed that there were no significant differences in the storage modulus or complex modulus between the two age groups (18-25 versus 54-83 yrs) for either the intertubular or peritubular tissue. However, there were significant differences in the dampening behavior between the young and old dentin, as represented in the loss modulus and tanδ responses. For both the intertubular and peritubular components, the capacity for dampening was significantly lower in the old group. Scanning based nanoDMA showed that the tubules of old dentin exhibit a gradient in elastic behavior, with decrease in elastic modulus from the cuff to the center of tubules filled with newly deposited mineral.
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44
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Ryan AJ, Gleeson JP, Matsiko A, Thompson EM, O'Brien FJ. Effect of different hydroxyapatite incorporation methods on the structural and biological properties of porous collagen scaffolds for bone repair. J Anat 2014; 227:732-45. [PMID: 25409684 DOI: 10.1111/joa.12262] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/27/2014] [Indexed: 01/08/2023] Open
Abstract
Scaffolds which aim to provide an optimised environment to regenerate bone tissue require a balance between mechanical properties and architecture known to be conducive to enable tissue regeneration, such as a high porosity and a suitable pore size. Using freeze-dried collagen-based scaffolds as an analogue of native ECM, we sought to improve the mechanical properties by incorporating hydroxyapatite (HA) in different ways while maintaining a pore architecture sufficient to allow cell infiltration, vascularisation and effective bone regeneration. Specifically we sought to elucidate the effect of different hydroxyapatite incorporation methods on the mechanical, morphological, and cellular response of the resultant collagen-HA scaffolds. The results demonstrated that incorporating either micron-sized (CHA scaffolds) or nano-sized HA particles (CnHA scaffolds) prior to freeze-drying resulted in moderate increases in stiffness (2.2-fold and 6.2-fold, respectively, vs. collagen-glycosaminoglycan scaffolds, P < 0.05, a scaffold known to support osteogenesis), while enabling good cell attachment, and moderate mesenchymal stem cell (MSC)-mediated calcium production after 28 days' culture (2.1-fold, P < 0.05, and 1.3-fold, respectively, vs. CG scaffolds). However, coating of collagen scaffolds with a hydroxyapatite precipitate after freeze-drying (CpHA scaffolds) has been shown to be a highly effective method to increase the compressive modulus (26-fold vs. CG controls, P < 0.001) of scaffolds while maintaining a high porosity (~ 98%). The coating of the ligand-dense collagen structure results in a lower cell attachment level (P < 0.05), although it supported greater cell-mediated calcium production (P < 0.0001) compared with other scaffold variants after 28 days' culture. The comparatively good mechanical properties of these high porosity scaffolds is obtained partially through highly crosslinking the scaffolds with both a physical (DHT) and chemical (EDAC) crosslinking treatment. Control of scaffold microstructure was examined via alterations in freezing temperature. It was found that the addition of HA prior to freeze-drying generally reduced the pore size and so the CpHA scaffold fabrication method offered increased control over the resulting scaffolds microstructure. These findings will help guide future design considerations for composite biomaterials and demonstrate that the method of HA incorporation can have profound effects on the resulting scaffold structural and biological response.
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Affiliation(s)
- Alan J Ryan
- Tissue Engineering Research Group, Department of Anatomy, Royal College of Surgeons in Ireland, Dublin, Ireland.,Trinity Centre for Bioengineering, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland.,Advanced Materials and Bioengineering Research (AMBER) Centre, Royal College of Surgeons in Ireland and Trinity College Dublin, Dublin, Ireland
| | - John P Gleeson
- Tissue Engineering Research Group, Department of Anatomy, Royal College of Surgeons in Ireland, Dublin, Ireland.,Trinity Centre for Bioengineering, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland.,Advanced Materials and Bioengineering Research (AMBER) Centre, Royal College of Surgeons in Ireland and Trinity College Dublin, Dublin, Ireland.,SurgaColl Technologies Ltd, Rubicon Centre, Cork, Ireland
| | - Amos Matsiko
- Tissue Engineering Research Group, Department of Anatomy, Royal College of Surgeons in Ireland, Dublin, Ireland.,Trinity Centre for Bioengineering, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland.,Advanced Materials and Bioengineering Research (AMBER) Centre, Royal College of Surgeons in Ireland and Trinity College Dublin, Dublin, Ireland
| | - Emmet M Thompson
- Tissue Engineering Research Group, Department of Anatomy, Royal College of Surgeons in Ireland, Dublin, Ireland.,Trinity Centre for Bioengineering, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland.,Advanced Materials and Bioengineering Research (AMBER) Centre, Royal College of Surgeons in Ireland and Trinity College Dublin, Dublin, Ireland
| | - Fergal J O'Brien
- Tissue Engineering Research Group, Department of Anatomy, Royal College of Surgeons in Ireland, Dublin, Ireland.,Trinity Centre for Bioengineering, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland.,Advanced Materials and Bioengineering Research (AMBER) Centre, Royal College of Surgeons in Ireland and Trinity College Dublin, Dublin, Ireland
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Cyclic cryopreservation affects the nanoscale material properties of trabecular bone. J Biomech 2014; 47:3584-9. [PMID: 25278046 DOI: 10.1016/j.jbiomech.2014.08.027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Revised: 08/22/2014] [Accepted: 08/30/2014] [Indexed: 11/24/2022]
Abstract
Tissues such as bone are often stored via freezing, or cryopreservation. During an experimental protocol, bone may be frozen and thawed a number of times. For whole bone, the mechanical properties (strength and modulus) do not significantly change throughout five freeze-thaw cycles. Material properties at the trabecular and lamellar scales are distinct from whole bone properties, thus the impact of freeze-thaw cycling at this scale is unknown. To address this, the effect of repeated freezing on viscoelastic material properties of trabecular bone was quantified via dynamic nanoindentation. Vertebrae from five cervine spines (1.5-year-old, male) were semi-randomly assigned, three-to-a-cycle, to 0-10 freeze-thaw cycles. After freeze-thaw cycling, the vertebrae were dissected, prepared and tested. ANOVA (factors cycle, frequency, and donor) on storage modulus, loss modulus, and loss tangent, were conducted. Results revealed significant changes between cycles for all material properties for most cycles, no significant difference across most of the dynamic range, and significant differences between some donors. Regression analysis showed a moderate positive correlation between cycles and material property for loss modulus and loss tangent, and weak negative correlation for storage modulus, all correlations were significant. These results indicate that not only is elasticity unpredictably altered, but also that damping and viscoelasticity tend to increase with additional freeze-thaw cycling.
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46
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Yallapu MM, Katti KS, Katti DR, Mishra SR, Khan S, Jaggi M, Chauhan SC. The roles of cellular nanomechanics in cancer. Med Res Rev 2014; 35:198-223. [PMID: 25137233 DOI: 10.1002/med.21329] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The biomechanical properties of cells and tissues may be instrumental in increasing our understanding of cellular behavior and cellular manifestations of diseases such as cancer. Nanomechanical properties can offer clinical translation of therapies beyond what are currently employed. Nanomechanical properties, often measured by nanoindentation methods using atomic force microscopy, may identify morphological variations, cellular binding forces, and surface adhesion behaviors that efficiently differentiate normal cells and cancer cells. The aim of this review is to examine current research involving the general use of atomic force microscopy/nanoindentation in measuring cellular nanomechanics; various factors and instrumental conditions that influence the nanomechanical properties of cells; and implementation of nanoindentation methods to distinguish cancer cells from normal cells or tissues. Applying these fundamental nanomechanical properties to current discoveries in clinical treatment may result in greater efficiency in diagnosis, treatment, and prevention of cancer, which ultimately can change the lives of patients.
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Affiliation(s)
- Murali M Yallapu
- Department of Pharmaceutical Sciences and Center for Cancer Research, College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee, 38163
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Schwiedrzik J, Raghavan R, Bürki A, LeNader V, Wolfram U, Michler J, Zysset P. In situ micropillar compression reveals superior strength and ductility but an absence of damage in lamellar bone. NATURE MATERIALS 2014; 13:740-747. [PMID: 24907926 DOI: 10.1038/nmat3959] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Accepted: 03/27/2014] [Indexed: 06/03/2023]
Abstract
Ageing societies suffer from an increasing incidence of bone fractures. Bone strength depends on the amount of mineral measured by clinical densitometry, but also on the micromechanical properties of the hierarchical organization of bone. Here, we investigate the mechanical response under monotonic and cyclic compression of both single osteonal lamellae and macroscopic samples containing numerous osteons. Micropillar compression tests in a scanning electron microscope, microindentation and macroscopic compression tests were performed on dry ovine bone to identify the elastic modulus, yield stress, plastic deformation, damage accumulation and failure mechanisms. We found that isolated lamellae exhibit a plastic behaviour, with higher yield stress and ductility but no damage. In agreement with a proposed rheological model, these experiments illustrate a transition from a ductile mechanical behaviour of bone at the microscale to a quasi-brittle response driven by the growth of cracks along interfaces or in the vicinity of pores at the macroscale.
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Affiliation(s)
- Jakob Schwiedrzik
- Institute for Surgical Technology and Biomechanics, University of Bern, Stauffacherstr. 78 CH-3014 Bern, Switzerland
| | - Rejin Raghavan
- 1] EMPA, Swiss Federal Laboratories for Material Science and Technology, Laboratory of Mechanics of Materials and Nanostructures, Feuerwerkerstr. 39, CH-3602 Thun, Switzerland [2]
| | - Alexander Bürki
- Institute for Surgical Technology and Biomechanics, University of Bern, Stauffacherstr. 78 CH-3014 Bern, Switzerland
| | - Victor LeNader
- EMPA, Swiss Federal Laboratories for Material Science and Technology, Laboratory of Mechanics of Materials and Nanostructures, Feuerwerkerstr. 39, CH-3602 Thun, Switzerland
| | - Uwe Wolfram
- Institute for Surgical Technology and Biomechanics, University of Bern, Stauffacherstr. 78 CH-3014 Bern, Switzerland
| | - Johann Michler
- 1] EMPA, Swiss Federal Laboratories for Material Science and Technology, Laboratory of Mechanics of Materials and Nanostructures, Feuerwerkerstr. 39, CH-3602 Thun, Switzerland [2]
| | - Philippe Zysset
- 1] Institute for Surgical Technology and Biomechanics, University of Bern, Stauffacherstr. 78 CH-3014 Bern, Switzerland [2]
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Dudeck J, Rehberg S, Bernhardt R, Schneiders W, Zierau O, Inderchand M, Goebbels J, Vollmer G, Fratzl P, Scharnweber D, Rammelt S. Increased bone remodelling around titanium implants coated with chondroitin sulfate in ovariectomized rats. Acta Biomater 2014; 10:2855-65. [PMID: 24534718 DOI: 10.1016/j.actbio.2014.01.034] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Revised: 01/25/2014] [Accepted: 01/31/2014] [Indexed: 01/23/2023]
Abstract
Coating titanium implants with artificial extracellular matrices based on collagen and chondroitin sulfate (CS) has been shown to enhance bone remodelling and de novo bone formation in vivo. The aim of this study was to evaluate the effect of estrogen deficiency and hormone replacement therapy (HRT) on the osseointegration of CS-modified Ti implants. 30 adult female, ovariectomized Wistar rats were fed either with an ethinyl-estradiol-rich diet (E) to simulate a clinical relevant HRT or with a genistein-rich diet (G) to test an alternative therapy based on nutritionally relevant phytoestrogens. Controls (C) received an estrogen-free diet. Uncoated titanium pins (Ti) or pins coated with type-I collagen and CS (Ti/CS) were inserted 8weeks after ovarectomy into the tibia. Specimens were retrieved 28days after implantation. Both the amount of newly formed bone and the affinity index (P<0.05) were moderately higher around Ti/CS implants as compared to uncoated Ti. The highest values were measured in the G-Ti/CS and E-Ti/CS groups, the lowest values for the E-Ti and G-Ti controls. Quantitative synchrotron radiation micro-computed tomography (SRμCT) revealed the highest increase in total bone formation around G-Ti/CS as compared to C-Ti (P<0.01). The effects with respect to direct bone apposition were less pronounced with SRμCT. Using scanning nanoindentation, both the indentation modulus and the hardness of the newly formed bone were highest in the E-Ti/CS, G-Ti/CS and G-Ti groups as compared to C-Ti (P<0.05). Coatings with collagen and CS appear to improve both the quantity and quality of bone formed around Ti implants in ovarectomized rats. A simultaneous ethinyl estradiol- and genistein-rich diet seems to enhance these effects.
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Kolli V, Stechschulte LA, Dowling AR, Rahman S, Czernik PJ, Lecka-Czernik B. Partial agonist, telmisartan, maintains PPARγ serine 112 phosphorylation, and does not affect osteoblast differentiation and bone mass. PLoS One 2014; 9:e96323. [PMID: 24810249 PMCID: PMC4014504 DOI: 10.1371/journal.pone.0096323] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Accepted: 04/07/2014] [Indexed: 11/30/2022] Open
Abstract
Peroxisome proliferator activated receptor gamma (PPARγ) controls both glucose metabolism and an allocation of marrow mesenchymal stem cells (MSCs) toward osteoblast and adipocyte lineages. Its activity is determined by interaction with a ligand which directs posttranscriptional modifications of PPARγ protein including dephosphorylation of Ser112 and Ser273, which results in acquiring of pro-adipocytic and insulin-sensitizing activities, respectively. PPARγ full agonist TZD rosiglitazone (ROSI) decreases phosphorylation of both Ser112 and Ser273 and its prolonged use causes bone loss in part due to diversion of MSCs differentiation from osteoblastic toward adipocytic lineage. Telmisartan (TEL), an anti-hypertensive drug from the class of angiotensin receptor blockers, also acts as a partial PPARγ agonist with insulin-sensitizing and a weak pro-adipocytic activity. TEL decreased S273pPPARγ and did not affect S112pPPARγ levels in a model of marrow MSC differentiation, U-33/γ2 cells. In contrast to ROSI, TEL did not affect osteoblast phenotype and actively blocked ROSI-induced anti-osteoblastic activity and dephosphorylation of S112pPPARγ. The effect of TEL on bone was tested side-by-side with ROSI. In contrast to ROSI, TEL administration did not affect bone mass and bone biomechanical properties measured by micro-indentation method and did not induce fat accumulation in bone, and it partially protected from ROSI-induced bone loss. In addition, TEL induced “browning” of epididymal white adipose tissue marked by increased expression of UCP1, FoxC2, Wnt10b and IGFBP2 and increased overall energy expenditure. These studies point to the complexity of mechanisms by which PPARγ acquires anti-osteoblastic and pro-adipocytic activities and suggest an importance of Ser112 phosphorylation status as being a part of the mechanism regulating this process. These studies showed that TEL acts as a full PPARγ agonist for insulin-sensitizing activity and as a partial agonist/partial antagonist for pro-adipocytic and anti-osteoblastic activities. They also suggest a relationship between PPARγ fat “browning” activity and a lack of anti-osteoblastic activity.
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Affiliation(s)
- Vipula Kolli
- Department of Orthopaedic Surgery, University of Toledo College of Medicine, Toledo, Ohio, United States of America
- Center for Diabetes and Endocrine Research, University of Toledo College of Medicine, Toledo, Ohio, United States of America
| | - Lance A. Stechschulte
- Department of Orthopaedic Surgery, University of Toledo College of Medicine, Toledo, Ohio, United States of America
- Center for Diabetes and Endocrine Research, University of Toledo College of Medicine, Toledo, Ohio, United States of America
| | - Abigail R. Dowling
- Department of Physiology and Pharmacology, University of Toledo College of Medicine, Toledo, Ohio, United States of America
- Center for Diabetes and Endocrine Research, University of Toledo College of Medicine, Toledo, Ohio, United States of America
| | - Sima Rahman
- Department of Orthopaedic Surgery, University of Toledo College of Medicine, Toledo, Ohio, United States of America
- Center for Diabetes and Endocrine Research, University of Toledo College of Medicine, Toledo, Ohio, United States of America
| | - Piotr J. Czernik
- Department of Orthopaedic Surgery, University of Toledo College of Medicine, Toledo, Ohio, United States of America
| | - Beata Lecka-Czernik
- Department of Orthopaedic Surgery, University of Toledo College of Medicine, Toledo, Ohio, United States of America
- Department of Physiology and Pharmacology, University of Toledo College of Medicine, Toledo, Ohio, United States of America
- Center for Diabetes and Endocrine Research, University of Toledo College of Medicine, Toledo, Ohio, United States of America
- * E-mail:
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50
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Size dependent elastic modulus and mechanical resilience of dental enamel. J Biomech 2014; 47:1060-6. [DOI: 10.1016/j.jbiomech.2013.12.030] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Revised: 12/12/2013] [Accepted: 12/22/2013] [Indexed: 11/22/2022]
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