Effect of freeze–thaw cycles on load transfer between the biomineral and collagen phases in bovine dentin

Stabilization of biological materials by freezing is widespread in the fields of medicine and biomaterials research and yet, in the case of hard biomaterials such as dentin, there is not a good understanding of how such treatments might affect the mechanical properties. The freezing and thawing may have a number of different effects on dentin including formation of cracks in the microstructure and denaturation of the collagen. Using high-energy synchrotron X-ray diffraction, the apparent moduli of bovine dentin samples were measured before and after various numbers of freeze–thaw cycles. It was determined that repeated freezing and thawing has no measurable effect on the hydroxyapatite or fibrillar apparent moduli up to 10 cycles. This confirms that the use of low temperature storage for stabilization of dentin is reasonable in cases where stiffness is a property of importance.

► Studied the effect of freezing on the load transfer of HAP and fibrils in dentin.
► X-ray scattering measured HAP and fibril apparent moduli vs. freezing cycles.
► Apparent moduli did not vary significantly between 0 and 10 freeze thaw cycles.
► Residual strains imply no widespread cracking due to volumetric expansion of water.
► Dentin can be freeze-thawed with no significant effects on elastic properties.