For regenerated tissue to be fully functional, it must exhibit the mechanical integrity of normal tissue. Because of the composite nature of tissues, regional variation in properties, and the fact that macroscopic mechanical testing is not always feasible with regenerated tissue, microscopic approaches are needed to better delineate structure-function relations. We have been utilizing an atomic force microscope (AFM) in conjunction with a picoindentation attachment to determine local, sub-micron level mechanical properties of normal and regenerated tissues. As representative data to establish the validity of this approach, regional hardness and stiffness values for dentin are presented. Repeated measures ANOVA indicated that moduli were site-specific. However, local variations at a given point (e.g. properties at <1 mu m spatial displacement) were less than site to site variations, validating the efficacy of the technique. Hardness and elasticity may be considered quantitative measures of degree of mineralization, enabling linkage between mechanical, structural, and biological measures of tissue regeneration.
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