Determination of Elastic Modulus in Mouse Bones Using a Nondestructive Micro-Indentation Technique Using Reference...

Area of Science:

• Biomaterials Science
• Orthopedic Biomechanics
• Materials Science

Background:

• Determining bone's elastic modulus is crucial for understanding its response to loading.
• Traditional three-point bending methods are destructive and impractical for in vivo applications.
• Reference point indentation (RPI) presents a nondestructive alternative for elastic modulus assessment.

Purpose of the Study:

• To explore Reference Point Indentation (RPI) as a nondestructive method for estimating bone's elastic modulus.
• To develop and validate a numerical analysis procedure using the Oliver-Pharr (O/P) method for RPI.
• To compare RPI-derived elastic modulus values with traditional three-point bending measurements.

Main Methods:

• Utilized RPI measurements including total indentation distance (TID) and creep indentation distance.
• Developed a numerical analysis procedure based on the Oliver-Pharr (O/P) method to estimate indentation elastic modulus.
• Employed two methods for area function determination: O/P-based numerical procedure and geometric calculation of projected indentation area.

Main Results:

• Indentation moduli of polymethyl methacrylate (PMMA) using O/P and geometric methods aligned with literature values.
• In mouse femurs, RPI-derived indentation modulus was generally higher than the three-point bending modulus.
• Specific findings in TOPGAL mice and female mice showed higher indentation moduli compared to three-point bending moduli.

Conclusions:

• RPI provides a viable nondestructive alternative for determining bone's elastic modulus.
• The developed numerical analysis procedure using O/P and geometric methods effectively estimates indentation elastic modulus.
• RPI-determined elastic modulus values are comparable and potentially advantageous over destructive three-point bending methods, especially for in vivo studies.