It is known that NMR proton spin-spin (T2) or spin-lattice (T1) relaxation time measurements and analytical processing techniques have been used to determine microstructural characteristics of various types of fluid filled porous materials with characteristic pore sizes ranging from sub-micron to sub-millimeter. Currently this method has been developed and applied to quantify the porosity, pore size distribution and microdamage in human cortical bone [1–3]. The observed proton NMR relaxation signals are a convolution of the relaxation of fluid in the pores throughout the observed system with the longer relaxation time corresponding to larger pore sizes. Thus, regions within the bone matrix in which fluid may accumulate can effectively be treated as a “pore” and will be manifest as a change in the relaxation signal. Deconvolution of the relaxation signal can provide quantitative information about the relaxation distributions of fluid inside bone, i.e., the distribution of water within bone tissue. Since teeth are comprised of fluid-filled porous materials, and dentin is like bone, we also applied this rapid, non-destructive and non-invasive technique to detect and quantify age-related teeth structural changes particularly for both dentin and pulp based on broadline pulsed NMR.

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