Tissue level mechanical properties of cortical bone in skeletally immature and mature dogs

2009 ◽  
Vol 22 (03) ◽  
pp. 210-215 ◽  
Author(s):  
C.A. Phillips ◽  
S.A. Fernandez ◽  
Y. Li ◽  
S.S. Huja
Keyword(s):  
Mechanical Properties ◽  
Cortical Bone ◽  
Tissue Level ◽  
Mechanical Tests ◽  
Indentation Modulus ◽  
Skeletally Immature ◽  
Beagle Dogs ◽  
Cross Sectional ◽  
Specimen Holder ◽  
Immature Group

Summary Objectives: The purpose of this study was to quantify the tissue level mechanical properties of cortical bone of skeletally immature (~five-month-old) Beagle dogs and compare them to data from mature dogs measured in a previous study. Methods: Eight femoral cross sectional specimens (two bone sections / dog) were obtained from four skeletally immature dogs. A pair of calcein bone labels were administered intravenously to the dogs to mark sites of active mineralization prior to euthanasia. Prepared bone specimens were placed in a nanoindenter specimen holder and the previously identified calcein labelled osteons were located. Labelled (n = 128) and neighbouring unlabelled (n = 127) osteons in skeletally immature femurs were examined by instrumented indentation testing. Indents were made to a depth of 500 nm at a loading rate of 10 nm/s. Indentation modulus (IM) and hardness (H) were obtained. Results: The overall IM of the cortical bone in the skeletally mature groups was significantly greater than in the immature group (p = 0.0011), however overall H was not significantly different. The differences between the groups in IM were significant for the unlabelled osteons (p = 0.001), but not for the labelled osteons (p = 0.56). Conclusion: There are differences in the IM of unlabelled osteons in skeletally immature and mature groups of Beagle dogs. In contrast to whole bone mechanical tests, where there are obvious differences between growing and mature bones, there are only small differences in the micro-mechanical properties.

scholarly journals Ultrastructural Changes in Articular Cartilages of Immature Beagle Dogs Dosed with Difloxacin, a Fluoroquinolone

1992 ◽  
Vol 29 (3) ◽  
pp. 230-238 ◽  
Author(s):  
J. E. Burkhardt ◽  
M. A. Hill ◽  
J. J. Turek ◽  
W. W. Carlton
Keyword(s):  
Extracellular Matrix ◽  
Body Weight ◽  
Electron Micrographs ◽  
Collagen Fibrils ◽  
Ultrastructural Changes ◽  
Pericellular Matrix ◽  
Skeletally Immature ◽  
Beagle Dogs ◽  
Cross Sectional ◽  
Articular Cartilages

The ultrastructural features of quinolone-induced arthropathy were studied in' the humeral and femoral heads of nine skeletally immature Beagle dogs (3 months old) that were dosed orally with difloxacin at 300 mg/kg body weight and euthanatized 24, 36, or 48 hours later in groups of three. Three age-matched dogs were given a placebo and euthanatized after 48 hours. Mitochondria in chondrocytes had significantly greater cross-sectional areas ( P < 0.05) in electron micrographs from dogs euthanatized after 48 hours of treatment than did those in other groups. There was also a significantly greater percentage of chondrocytes with swollen mitochondria in treated dogs than in the controls ( P < 0.05). These changes preceded the necrosis observed in some chondrocytes in the dogs of the 48-hour group. Disruption of extracellular matrix was first observed in the pericellular matrix of necrotic chondrocytes, indicating that this change was secondary to the changes in chondrocytes. Fissures within cartilages apparently resulted from the loss of the normal association of proteoglycans with collagen fibrils.

scholarly journals Tissue Level Mechanical Properties and Extracellular Matrix Investigation of the Bovine Jugular Venous Valve Tissue

2019 ◽  
Vol 6 (2) ◽  
pp. 45 ◽  
Author(s):  
Adam A. Benson ◽  
Hsiao-Ying Shadow Huang
Keyword(s):  
Mechanical Properties ◽  
Extracellular Matrix ◽  
Radial Direction ◽  
True Strain ◽  
Transient Global Amnesia ◽  
Tissue Level ◽  
Mechanical Tests ◽  
Circumferential Direction ◽  
Venous Valve ◽  
Venous Valves

Jugular venous valve incompetence has no long-term remedy and symptoms of transient global amnesia and/or intracranial hypertension continue to discomfort patients. During this study, we interrogate the synergy of the collagen and elastin microstructure that compose the bi-layer extracellular matrix (ECM) of the jugular venous valve. In this study, we investigate the jugular venous valve and relate it to tissue-level mechanical properties, fibril orientation and fibril composition to improve fundamental knowledge of the jugular venous valves toward the development of bioprosthetic venous valve replacements. Steps include: (1) multi loading biaxial mechanical tests; (2) isolation of the elastin microstructure; (3) imaging of the elastin microstructure; and (4) imaging of the collagen microstructure, including an experimental analysis of crimp. Results from this study show that, during a 3:1 loading ratio (circumferential direction: 900 mN and radial direction: 300 mN), elastin may have the ability to contribute to the circumferential mechanical properties at low strains, for example, shifting the inflection point toward lower strains in comparison to other loading ratios. After isolating the elastin microstructure, light microscopy revealed that the overall elastin orients in the radial direction while forming a crosslinked mesh. Collagen fibers were found undulated, aligning in parallel with neighboring fibers and orienting in the circumferential direction with an interquartile range of −10.38° to 7.58° from the circumferential axis (n = 20). Collagen crimp wavelength and amplitude was found to be 38.46 ± 8.06 µm and 4.51 ± 1.65 µm, respectively (n = 87). Analyzing collagen crimp shows that crimp permits about 12% true strain circumferentially, while straightening of the overall fibers accounts for more. To the best of the authors’ knowledge, this is the first study of the jugular venous valve linking the composition and orientation of the ECM to its mechanical properties and this study will aid in forming a structure-based constitutive model.

Mechanical Properties of Experimental Non-Latex Orthodontic Elastic Bands

2020 ◽  
Vol 897 ◽  
pp. 185-189
Author(s):  
Sasatorn Malanon ◽  
Surachai Dechkunakorn ◽  
Niwat Anuwongnukroh ◽  
Pongdhorn Sea-Oui ◽  
Puchong Thaptong ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tooth Movement ◽  
Orthodontic Tooth Movement ◽  
Mechanical Tests ◽  
Lower Percentage ◽  
Internal Diameter ◽  
Cross Sectional ◽  
Force Decay ◽  
Extension Force

. Elastics, a source of continuous orthodontic force, are divided into two types, latex and non-latex, which are made from natural rubber and synthetic rubber, respectively. The major advantage of natural latex elastics is its resiliency to intraoral tractive forces. However, as the incidence of allergic reactions to natural latex has become more widely recognized, non-latex orthodontic elastics have been developed as an alternative. The aim of this study is to investigate the in vitro mechanical properties of Thai non-latex orthodontic elastics as compared to commercially available products. 30 samples of each two Thai non-latex elastics (MTEC1, MTEC2) and two commercial elastics (AO, GAC) with a specified diameter of ¼ inches were used. Width, cross-sectional thickness (CT), and internal diameter (ID) of all samples were measured. Mechanical tests were then carried out to determine the initial extension force (F0), 24-hour residual force (F24), and percentage of force decay. The data were analyzed with one-way ANOVA and Tukey’s test (p < 0.05). Statistically significant differences in elastic width among all four groups except between the Thai non-latex groups (MTEC1 and MTEC2) were found. AO elastics showed the greatest CT followed by GAC, MTEC2 and MTEC1. ID was significantly highest in GAC elastics and lowest in MTEC1 elastics. Although MTEC1 elastics had the lowest F0, the force still falls within the acceptable range for tooth movement (100-250g or 0.981–1.471N). MTEC2 elastics had the greatest F24 and also the lowest percentage of force decay followed by MTEC1, GAC, and AO elastics, which displayed the highest force decay, though no significant differences were found between the two commercial elastics. Thai non-latex elastics are suitable for orthodontic tooth movement due to its lower percentage of force decay after 24 hours.

scholarly journals Analysis of Mechanical Properties and Mechanical Anisotropy in Canine Bone Tissues of Various Ages

2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
Changqi Luo ◽  
Junyi Liao ◽  
Zhenglin Zhu ◽  
Xiaoyu Wang ◽  
Xiao Lin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Cortical Bone ◽  
Bone Tissue ◽  
Poisson Ratio ◽  
Age Groups ◽  
Distal Region ◽  
Mechanical Anisotropy ◽  
Age Group ◽  
Cross Sectional

The effect of age on mechanical behavior and microstructure anisotropy of bone is often ignored by researchers engaged in the study of biomechanics. The objective of our study was to determine the variations in mechanical properties of canine femoral cortical bone with age and the mechanical anisotropy between the longitudinal and transverse directions. Twelve beagles divided into three age groups (6, 12, and 36 months) were sacrificed and all femurs were extracted. The longitudinal and transverse samples of cortical bone were harvested from three regions of diaphysis (proximal, central, and distal). A nanoindentation technique was used for simultaneously measuring force and displacement of a diamond tip pressed 2000nm into the hydrated bone tissue. An elastic modulus was calculated from the unloading curve with an assumed Poisson ratio of 0.3, while hardness was defined as the maximal force divided by the corresponding contact area. The mechanical properties of cortical bone were determined from 852 indents on two orthogonal cross-sectional surfaces. Mean elastic modulus ranged from 7.56±0.32 GPa up to 21.56±2.35 GPa, while mean hardness ranged from 0.28±0.057 GPa up to 0.84±0.072 GPa. Mechanical properties of canine femoral cortical bone tended to increase with age, but the magnitudes of these increase for each region might be different. The longitudinal mechanical properties were significantly higher than that of transverse direction (P<0.01). A significant anisotropy was found in the mechanical properties while there was no significant correlation between the two orthogonal directions in each age group (r2<0.3). Beyond that, the longitudinal mechanical properties of the distal region in each age group were lower than the proximal and central regions. Hence, mechanical properties in nanostructure of bone tissue must differ mainly among age, sample direction, anatomical sites, and individuals. These results may help a number of researchers develop more accurate constitutive micromechanics models of bone tissue in future studies.

scholarly journals Bone material strength index as measured by impact microindentation is altered in patients with acromegaly

2017 ◽  
Vol 176 (3) ◽  
pp. 339-347 ◽  
Author(s):  
F Malgo ◽  
N A T Hamdy ◽  
T J Rabelink ◽  
H M Kroon ◽  
K M J A Claessen ◽  
...  
Keyword(s):  
Cortical Bone ◽  
Tissue Level ◽  
Material Strength ◽  
Strength Index ◽  
Mineral Density ◽  
Cross Sectional ◽  
Bone Material ◽  
Normal Bone Mineral Density ◽  
Bone Material Strength ◽  
Impact Microindentation

Objective Acromegaly is a rare disease caused by excess growth hormone (GH) production by the pituitary adenoma. The skeletal complications of GH and IGF-1 excess include increased bone turnover, increased cortical bone mass and deteriorated microarchitecture of trabecular bone, associated with a high risk of vertebral fractures in the presence of relatively normal bone mineral density (BMD). We aimed to evaluate tissue-level properties of bone using impact microindentation (IMI) in well-controlled patients with acromegaly aged ≥18 years compared to 44 controls from the outpatient clinic of the Centre for Bone Quality. Design and methods In this cross-sectional study, bone material strength index (BMSi) was measured in 48 acromegaly patients and 44 controls with impact microindentation using the osteoprobe. Results Mean age of acromegaly patients (54% male) was 60.2 years (range 37.9–76.5), and 60.5 years (range 39.8–78.6) in controls (50% male). Patients with acromegaly and control patients had comparable BMI (28.2 kg/m2 ± 4.7 vs 26.6 kg/m2 ± 4.3, P = 0.087) and comparable BMD at the lumbar spine (1.04 g/cm2 ± 0.21 vs 1.03 g/cm2 ± 0.13, P = 0.850) and at the femoral neck (0.84 g/cm2 ± 0.16 vs 0.80 g/cm2 ± 0.09, P = 0.246). BMSi was significantly lower in acromegaly patients than that in controls (79.4 ± 0.7 vs 83.2 ± 0.7; P < 0.001). Conclusion Our data indicates that tissue-level properties of cortical bone are significantly altered in patients with controlled acromegaly after reversal of long-term exposure to pathologically high GH and IGF-1 levels. Our findings also suggest that methods other than DXA should be considered to evaluate bone fragility in patients with acromegaly.

Mechanical properties of cancellous and cortical bone after long term ibandronate dosing in beagle dogs

Bone ◽  
1995 ◽  
Vol 17 (6) ◽  
pp. 604 ◽  
Author(s):  
U. Affentranger ◽  
F. Bauss ◽  
L. Oin ◽  
J. Cordey ◽  
T. Mclff ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cortical Bone ◽  
Beagle Dogs

Quantification of Age-Related Tissue-Level Failure Strains of Rat Femoral Cortical Bones Using an Approach Combining Macrocompressive Test and Microfinite Element Analysis

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
Ruoxun Fan ◽  
He Gong ◽  
Rui Zhang ◽  
Jiazi Gao ◽  
Zhengbin Jia ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cortical Bone ◽  
Failure Strain ◽  
Skeletal Maturity ◽  
Tissue Level ◽  
Male Rat ◽  
Bone Mechanical Properties ◽  
Age Related ◽  
Different Ages ◽  
Different Levels

Bone mechanical properties vary with age; meanwhile, a close relationship exists among bone mechanical properties at different levels. Therefore, conducting multilevel analyses for bone structures with different ages are necessary to elucidate the effects of aging on bone mechanical properties at different levels. In this study, an approach that combined microfinite element (micro-FE) analysis and macrocompressive test was established to simulate the failure of male rat femoral cortical bone. Micro-FE analyses were primarily performed for rat cortical bones with different ages to simulate their failure processes under compressive load. Tissue-level failure strains in tension and compression of these cortical bones were then back-calculated by fitting the experimental stress–strain curves. Thus, tissue-level failure strains of rat femoral cortical bones with different ages were quantified. The tissue-level failure strain exhibited a biphasic behavior with age: in the period of skeletal maturity (1–7 months of age), the failure strain gradually increased; when the rat exceeded 7 months of age, the failure strain sharply decreased. In the period of skeletal maturity, both the macro- and tissue-levels mechanical properties showed a large promotion. In the period of skeletal aging (9–15 months of age), the tissue-level mechanical properties sharply deteriorated; however, the macromechanical properties only slightly deteriorated. The age-related changes in tissue-level failure strain were revealed through the analysis of male rat femoral cortical bones with different ages, which provided a theoretical basis to understand the relationship between rat cortical bone mechanical properties at macro- and tissue-levels and decrease of bone strength with age.

scholarly journals Age-specific profiles of tissue-level composition and mechanical properties in murine cortical bone

Bone ◽  
2012 ◽  
Vol 50 (4) ◽  
pp. 942-953 ◽  
Author(s):  
Mekhala Raghavan ◽  
Nadder D. Sahar ◽  
David H. Kohn ◽  
Michael D. Morris
Keyword(s):  
Mechanical Properties ◽  
Cortical Bone ◽  
Tissue Level

Indentation Modulus of the Alveolar Process in Dogs

2007 ◽  
Vol 86 (3) ◽  
pp. 237-241 ◽  
Author(s):  
S.S. Huja ◽  
S.A. Fernandez ◽  
K.J. Hill ◽  
P. Gulati
Keyword(s):  
Cortical Bone ◽  
Alveolar Bone ◽  
Tissue Level ◽  
Bone Adaptation ◽  
Indentation Modulus ◽  
Alveolar Process ◽  
Significant Difference ◽  
Maxilla And Mandible ◽  
Anterior Posterior ◽  
Made In

One mechanism of bone adaptation is alteration in tissue level material properties. We hypothesized that alteration in the indentation modulus of the alveolar process is an adaptive response to the localized mechanical environment. Forty-eight specimens representing anterior and posterior regions of the maxilla and mandible were obtained from 6 mature male beagle dogs. The indentation properties of the alveolar bone proper and more distant osteonal cortical bone were estimated. The bone types were further divided into 3 regions (coronal, middle, and apical), with 27 indents being made in each region of tooth-supporting bone. There was a significant difference (p < 0.001) in the indentation moduli of the jaws (maxilla/mandible), location (anterior/posterior), and bone type (alveolar bone proper vs. cortical bone). However, statistical interactions exist which preclude the simple interpretation of results. The distribution of relative stiffness provides a better understanding of bone adaptations in the alveolar process.

scholarly journals Compositional and mechanical properties of growing cortical bone tissue: a study of the human fibula

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Emmanuelle Lefèvre ◽  
Delphine Farlay ◽  
Yohann Bala ◽  
Fabien Subtil ◽  
Uwe Wolfram ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cortical Bone ◽  
Mixed Model ◽  
Bone Mineralization ◽  
Organic Matrix ◽  
Interstitial Tissue ◽  
Indentation Modulus ◽  
Intrinsic Properties ◽  
Yield Strain ◽  
Adult Bone

AbstractHuman cortical bone contains two types of tissue: osteonal and interstitial tissue. Growing bone is not well-known in terms of its intrinsic material properties. To date, distinctions between the mechanical properties of osteonal and interstitial regions have not been investigated in juvenile bone and compared to adult bone in a combined dataset. In this work, cortical bone samples obtained from fibulae of 13 juveniles patients (4 to 18 years old) during corrective surgery and from 17 adult donors (50 to 95 years old) were analyzed. Microindentation was used to assess the mechanical properties of the extracellular matrix, quantitative microradiography was used to measure the degree of bone mineralization (DMB), and Fourier transform infrared microspectroscopy was used to evaluate the physicochemical modifications of bone composition (organic versus mineral matrix). Juvenile and adult osteonal and interstitial regions were analyzed for DMB, crystallinity, mineral to organic matrix ratio, mineral maturity, collagen maturity, carbonation, indentation modulus, indicators of yield strain and tissue ductility using a mixed model. We found that the intrinsic properties of the juvenile bone were not all inferior to those of the adult bone. Mechanical properties were also differently explained in juvenile and adult groups. The study shows that different intrinsic properties should be used in case of juvenile bone investigation.

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