QUANTITATIVE ELECTRON-SPECTROSCOPIC DIFFRACTION (ESD) AND ELECTRON-SPECTROSCOPIC IMAGING (ESI) ANALYSES OF DENTIN MINERALIZATION IN RAT INCISORS

Primary crystal formations in all hard tissues are, according to our i nvestigations, Ca-phosphate chains composed of nanometer sized particl es (dots) which develop along the matrix macromolecules. In circumpulp al dentine the centre-to-centre distances between the dots inside the chains reflect the distances between the crystal nucleating sites (''a ctive sites'') along the collagen matrix macromolecule. The centre-to- centre distances at the surface of the mineralised collagen fibrils pr obably reflect the distances between nucleating sites of noncollagenou s proteins attached to collagen. These needle-like chains of dots coal esce in lateral directions to form ribbon-like crystallites. The morph ological results are supported by correlated small area diffraction st udies in the same regions of dentine. We have found that the first app earing Bragg-reflection has a lattice spacing value of 0.388 nm, which corresponds to the (111) apatite value. For the earliest crystal form ations the intensity of the (002) reflection is higher than that of th e (300)-reflection A maximum of the net-signal-intensity ratio of the (002) to (300) Bragg-reflection appears at the mineralisation front. T his peak repeats with decreasing height 3 to 5 times with a distance r ange of about 8-16 mu m through the whole dentine zone, which correspo nds to the distances of the incremental lines, called ''von Ebner line s''.