Compression Testing of Bone in Tissue Engineering

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Compression Testing of Bone in Tissue Engineering
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• author names removed for anonymity

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DISCLAIMER

• This presentation is based on previously
  conducted research from Biophysical Properties of
  Materials, ABE 3813, and is being used with
  permission from Dr. James N. Warnock.
• Compression Testing of Bone, from lab
  handout for ABE 3813 Biophysical Properties of
  Materials Lab, Bagley College of Engineering,
  Mississippi State University, Spring 2008.

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OUTLINE

• Background
• Purpose
• Procedure
• Results
• Discussion
• Conclusion

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COMPOSITION OF BONE
-Hyaline Cartlidge- absorbs shock -Cancellous
Bone- contains bone marrow -Compact Bone-
characteristic hardness
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TISSUE ENGINEERING

• Encompasses partial and complete replacement
• Synthetic polymers ? difficult to create
• Autogeneous-bone from replacement recipient
• Allogenic-bone from a like subject of the
  recipient

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SYNTHETIC BONE GRAFT
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INSTRON MATERIAL TESTING MACHINE

• Performed compression testing in this experiment
• Components

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PURPOSE

• Helping to further the research of tissue
  engineering of bone
• Bone is load bearing
• Average strength is calculated to determine the
  standard strength the bone implants must reach or
  exceed

Left Titanium jaw implant, with the mesh
encouraging bone growth through the implant
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TESTING MATERIAL

• Porcine bone
• Six samples
• Three in axial direction
• Three in radial direction

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MECHANICAL TESTING

• Dimensions
• Preparing the Instron
• Load cell
• Computer program uploaded
• Bone placement
• Compression Test
• Load
• Displacement

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CALCULATIONS

• Areas (axial and radial)
• Strain - deformation of materials
• Stress intensity of the force on the specific
  area
• Stress-Strain curves plotted

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MECHANICAL PROPERTIES

• Ultimate Compressive Strength (UCS)
• maximum compressive strength a sample can
  withstand
• Total Percent Elongation
• specimen's fracture strain expressed as a
  percent

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MECHANICAL PROPERTIES

• Elastic Modulus (E)
• gradient of the elastic region
• Elastic Strain Energy Density
• the strain energy per unit volume

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DATA ANALYSIS

• Mechanical properties determined for six samples
• Three axial sample values were averaged
• Three radial sample values were averaged

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AVERAGE VALUES
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ANALYSIS OF RESULTS

• The stress-strain curves plotted for each sample
• Axial sample did not show definite breakage

Left Radial Stress-Strain curve
Right Axial Stress-Strain curve
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ANALYSIS OF RESULTS

• Hypothesis 3rd axial sample may have cracked
  internally

Above Stress-Strain Curve for 3rd Axial Sample
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DISCUSSION

• Mechanical property ? strength of the material
• Human error in lab
• Properties of bone can be altered

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CONCLUSIONS

• Bone is load bearing
• Strength is directly affected by
• Direction
• Mechanical Properties

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CONCLUSIONS

• Allogenic bone sample standards better
  understanding for researchers
• Data allows a standard to be set
• Synthetic polymers meet if not exceed these
  values
• This research sets a standard for the average
  values bone implants must be able to withstand
• Continued research will advance this field even
  further

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REFERENCES

• 1 J.E. Terrill, Visualization of Tissue
  Engineering, http//math.nist.gov/mcsd/savg/vis/t
  issue/index.html. Site last modified February 7,
  2008 accessed on June 20, 2008.
• 2 Composition of a Bone, http//healthbase.wor
  dpress.com/2007/03/22/composition-of-a-bone/.
  Site last modified March 22, 2007 accessed June
  17, 2008.
• 3 J. Meredith, Ceramic Monoliths for Bone
  Tissue Engineering, http//www2.warwick.ac.uk/fac
  /sci/wimrc/projects/student/tissue_engineering.
  Accessed June 20, 2008.
• 4 Introduction to the Instron Material Testing
  Machine, from lab handout for ABE 3813
  Biophysical Property of Materials Lab, Bagley
  College of Engineering, Mississippi State
  University, Spring 2008.
• 5 Centre for Biomaterials and Tissue
  Engineering, Tissue Engineering of Bone,
  http//www.cbte.group.shef.ac.uk/research/te4.html
  . Accessed June 20, 2008.
• 6 Compression Testing of Bone, from lab
  handout for ABE 3813 Biophysical Properties of
  Materials Lab, Bagley College of Engineering,
  Mississippi State University, Spring 2008.
• 7 Equipment, http//www.cals.ncsu.edu/foodrheo
  logy/documents/24.html. Accessed June 20,2008.
• 8 Stress-Strain Curve for Ductile Material,
  http//invsee.asu.edu/srinivas/stress-strain/phase
  .html. Accessed June 21, 2008.

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QUESTIONS????