The effects of loading conditions and specimen environment on the nanomechanical response of canine cortical bone

Lee, Kun-Lin; Sobieraj, Michael C.; Baldassarri, Marta; Gupta, Nïkhil; Pinisetty, Dinesh; Tovar, Nick; Coelho, Paulo G.

doi:10.1016/j.msec.2013.07.018

Cited by 11 publications

(13 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…30 The nanoindentation test showed that the mean H and E values for cortical bone were higher than for trabecular bone, irrespective of whether the implants were loaded or remained unloaded, but this result was not statistically different. The present results are in agreement with those of other studies of canine models 22,30 and human bone. 16,31 It is likely that the results obtained for cortical and trabecular bone were not statistically different, because the latter can be subject to changes to near-cortical-like bone from immediate loading.…”

Section: Discussionsupporting

confidence: 94%

“…20 A wax chamber was created above the acrylic plate around the implant-in-bone perimeter, which kept the sample fully immersed during the test (thrice-distilled water; neutral pH, 7.1). 21,22 A loading profile was developed with a peak load of 300 mN at a rate of 60 mN per second, followed by a holding time of 10 seconds and an unloading time of 2 seconds. The extended holding period allowed the bone to relax to a more linear response, so that no tissue creep effect occurred in the unloading portion of the profile.…”

Section: Nanoindentationmentioning

confidence: 99%

See 1 more Smart Citation

Nanomechanical Assessment of Bone Surrounding Implants Loaded for 3 Years in a Canine Experimental Model

Anchieta¹,

Guimaraes²,

Suzuki

et al. 2018

Journal of Oral and Maxillofacial Surgery

Self Cite

View full text Add to dashboard Cite

show abstract

Section: Discussionsupporting

confidence: 94%

Section: Nanoindentationmentioning

confidence: 99%

Nanomechanical Assessment of Bone Surrounding Implants Loaded for 3 Years in a Canine Experimental Model

Anchieta¹,

Guimaraes²,

Suzuki

et al. 2018

Journal of Oral and Maxillofacial Surgery

Self Cite

View full text Add to dashboard Cite

show abstract

“…Indeed, the biomechanical properties of bones are determined by composition and micro-/nano-structures, which can be dependent on factors such as anatomical locations and donor conditions [ 24 – 27 ]. Otherwise, the loading method was also an influence factor of bone micro-biomechanical characteristics [ 22 , 28 ]. In the present study, we applied nanoindentation technique to determine the elastic modulus and hardness of cortical and cancellous bones.…”

Section: Discussionmentioning

confidence: 99%

Effects of Moisture Content and Loading Profile on Changing Properties of Bone Micro-Biomechanical Characteristics

Wang

Chen

et al. 2018

Med Sci Monit

View full text Add to dashboard Cite

BackgroundOur study explored the influences of hydration conditions and loading methods on the mechanical properties of cortical bones and cancellous bones.Material/MethodsElastic modulus and hardness of human cortical bones and cancellous bones that contained different moisture levels (20%, 30%, 40%, 50%, and 60%) were measured with nanoindentation with different peak loads and loading rates. Cortical bones with 20% and 60% moisture were tested with 30 nm, 40 nm, and 50 nm peak loads at 6 nm/s, 8 nm/s, and 10 nm/s loading rates, respectively. Cancellous bones with 5% or 40% moisture percentages were tested with 600 μN, 750 μN, and 1000 μN peak loads at 200 μN/s, 250 μN/s, and 333 μN/s loading rates, respectively.ResultsUnder the same loading condition, specimens with higher moisture contents showed decreased elastic modulus and hardness. Under different loading conditions, the loading modes had little influence on elastic modulus and hardness of cortical bone and cancellous bone with low moisture, but had significant influence on specimens with higher moistures.ConclusionsThe elastic modulus and bone hardness were affected by the moisture content and the loading conditions in cortical and cancellous bones with high hydration condition but not in those with low hydration condition.

show abstract

“…Rehydration of the slides was performed by storing each specimen in nanopure water (18.2 MΩ; Millipore, USA) at room temperature for 1 hr prior to the test. Immediately before the test, nanopure water droplets were added for testing under wet environmental conditions (Doerner & Nix, ; Lee et al, ). Previous studies have illustrated that nanoindentation of bone should be performed in a wet environment, as the hydrated tissues show a pronounced viscoelastic behaviour with the higher loading rates significantly altering the interaction of collagen/water and the water flow, leading to higher mechanical properties (Kulin, Jiang, & Vecchio, ; Ntim, Bembey, Ferguson, et al, ).…”

Section: Methodsmentioning

confidence: 99%

“…From each analysed load–displacement curve (Figure b), reduced elastic modulus, E r , (GPa) and hardness, H , (GPa) of bone tissue were computed via the Hysitron TriboScan Software with the following formulas, respectively:

E_{r} = \frac{\sqrt{normalπ}}{2 \sqrt{A ((), h_{c})}} \times S,

H = \frac{P_{\max}}{A ((), h_{c})},

where S is the stiffness, h c is the contact depth, P max is the maximum force (300 μN) and A ( h c ) is the contact area computed from the Hysitron TriboScan software taking into account the area function with respect to contact depth (Oliver & Pharr, ). From the reduced modulus, E r , the reduced elastic modulus of the bone ( E b ) was calculated using the following relationship derived from Hertzian contact mechanics:

E_{b} = \frac{((), 1 - ν_{b}^{2}) E_{i} E_{r}}{E_{i} - ((), 1 - ν_{i}^{2}) E_{r}},

where v b is the Poisson's ratio of the bone and E i and v i are the elastic modulus and Poisson's ratio of the indenter, respectively (Hoffler, Guo, Zysset, et al, ; Lee et al, ; Oliver & Pharr, ). After nanoindentation was completed, slides were imaged under light microscopy (Zeiss Axiolmager M1 m, Carl Zeiss Microscopy, Thornwood, NY) and scanning electron microscopy (SEM) for verification of indents for samples.…”

Section: Methodsmentioning

confidence: 99%

Form and functional repair of long bone using 3D‐printed bioactive scaffolds

Tovar

Witek

Atria

et al. 2018

J Tissue Eng Regen Med

Self Cite

114

View full text Add to dashboard Cite

Injuries to the extremities often require resection of necrotic hard tissue. For large-bone defects, autogenous bone grafting is ideal but, similar to all grafting procedures, is subject to limitations. Synthetic biomaterial-driven engineered healing offers an alternative approach. This work focuses on three-dimensional (3D) printing technology of solid-free form fabrication, more specifically robocasting/direct write. The research hypothesizes that a bioactive calcium-phosphate scaffold may successfully regenerate extensive bony defects in vivo and that newly regenerated bone will demonstrate mechanical properties similar to native bone as healing time elapses. Robocasting technology was used in designing and printing customizable scaffolds, composed of 100% beta tri-calcium phosphate (β-TCP), which were used to repair critical sized long-bone defects. Following full thickness segmental defects (~11 mm × full thickness) in the radial diaphysis in New Zealand white rabbits, a custom 3D-printed, 100% β-TCP, scaffold was implanted or left empty (negative control) and allowed to heal over 8, 12, and 24 weeks. Scaffolds and bone, en bloc, were subjected to micro-CT and histological analysis for quantification of bone, scaffold and soft tissue expressed as a function of volume percentage. Additionally, biomechanical testing at two different regions, (a) bone in the scaffold and (b) in native radial bone (control), was conducted to assess the newly regenerated bone for reduced elastic modulus (E ) and hardness (H) using nanoindentation. Histological analysis showed no signs of any adverse immune response while revealing progressive remodelling of bone within the scaffold along with gradual decrease in 3D-scaffold volume over time. Micro-CT images indicated directional bone ingrowth, with an increase in bone formation over time. Reduced elastic modulus (E ) data for the newly regenerated bone presented statistically homogenous values analogous to native bone at the three time points, whereas hardness (H) values were equivalent to the native radial bone only at 24 weeks. The negative control samples showed limited healing at 8 weeks. Custom engineered β-TCP scaffolds are biocompatible, resorbable, and can directionally regenerate and remodel bone in a segmental long-bone defect in a rabbit model. Custom designs and fabrication of β-TCP scaffolds for use in other bone defect models warrant further investigation.

show abstract

The effects of loading conditions and specimen environment on the nanomechanical response of canine cortical bone

Cited by 11 publications

References 35 publications

Nanomechanical Assessment of Bone Surrounding Implants Loaded for 3 Years in a Canine Experimental Model

Nanomechanical Assessment of Bone Surrounding Implants Loaded for 3 Years in a Canine Experimental Model

Effects of Moisture Content and Loading Profile on Changing Properties of Bone Micro-Biomechanical Characteristics

Form and functional repair of long bone using 3D‐printed bioactive scaffolds

Contact Info

Product

Resources

About