In recent years, the biomineralization process has attracted much interest from academics and industries for potential technological application. The rule in biomineralization is to have a variety of interfaces and surfaces which can act as nucleators. The ultimate step in any biomineralization process, i.e. the deposition of mineral, must conform to the driving forces operating on the system. A new paradigm in the assessment of the driving force for biomineralization is that a variety of ions existing in the mineralizing milieu are not a bystander, but are instead an active player that directly regulates the precipitation process and nature of biogenic apatites. Thus, the most putative stoichiometric model of a biomineral is (Ca)(5-x)(Mg)q(Na)u(HPO4)v(CO3)w(PO4)(3-y)(OH,F)(1-z). Fluoride participates in many aspects of calcium phosphate formation in vivo and has enormous effects on its process and on the nature and properties of the final products. In the development of biogenic apatites, fluoride ion in the mineralizing media is supposed to accelerate the hydrolysis of acidic precursor(s) and increase the growth rates by augmenting the driving force for precipitation. Inhibitory activities of ions and molecules are related to their adsorption onto the apatite surfaces. From theoretical and practical points of view, it is of paramount importance to elucidate and predict the effect and outcome of fluoride (accelerator) and inhibitors of biological relevance, because of their use in combination for healthcare in dentistry and medicine, e.g. prevention of dental caries and calculus deposition and in the formulation of antiosteoporosis treatments.

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and Aoba T. Tissue maturation of fibro-osseous lesions with respect to the inorganic constituents and crystallographic features. Oral Med

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Abstract:Acquisition of substantial amounts of CO32-, HPO42-and other impurities is universally encountered in bioapatites from mammals. To date, however, there is a paucity of information about the stoichiometry and, on that basis, solubility product of dentin mineral. In this report, we summarize our experimental approach toward the determination of the stoichiometry model and thermodynamic solubility products of human dentin apatites. Dentin samples were collected separately from the coronal portion of permanent premolars (extracted for orthodontic reasons) and exfoliated deciduous teeth. Both pooled organic matter. The stoichiometry model selected for these crystals was (Ca)5 -x (Mg)q (Na)u (HPO4)v (CO3)w (PO4)3-y (OH)1-z. These stoichiometric coefficients were analytically determined by assessing separately the labile or surface pools of the ionic species on the crystal surface and their stable pools in the bulk for a maximum of 28 days under constant partial pressures of CO2 . The results showed that there are appreciable differences in the crystal stoichiometry between the permanent and deciduous dentin mineral deciduous dentin, which were determined under 1 .8% CO2/N2. Notably, the solubility properties of the dentin mineral remained relatively constant in the range of 1 .0 through 3.3% CO2/N2, whereas the discrete solubility data were obtained below and above the corresponding partial pressure of CO2 .

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The present study investigated the crystal-protein -protease interaction and the resulting effects on mineral precipitation under experimental conditions assimilated to those found in the en amel fluid surrounding the secretory enamel mineral . Materials used were synthetic hydroxyapatite , enamel proteins isolated from porcine secretory enamel , and trypsin as a prototype of enamel proteases . Two anti-peptide sera, reactive with the C-terminal epitope (s) of amelogenins , were used to assign the amelogenins and degraded products. It was verified that trypsin initially cleaved the hydrophilic domain of the secreted amelogenins in the liquid phase because the corresponding domain is likely exposed on protein surface.