ABSTRACT

This chapter focuses on the biological factors that determine the stability of the biominerals under physiological and eventually pathological conditions. In order to relate the biological stability of the biominerals with these concepts published concerning their nature, an estimate about the physicochemical factors that determine the stability of these biominerals is presented. Polycrystalline calcium phosphates can be obtained in the form of a loose powder by precipitation from aqueous solution. Calcium phosphates used mainly as substitutes for or improvement of calcified tissues such as bone and dental hard tissues. Cameron and Hurst have mentioned the existence of dicalcium phosphate, dicalcium phosphate dihydrate, tricalcium phosphate, and apatite, of which all but the latter were characterized by their chemical composition at that time, whereas apatite was known as a mineral. Preparation of calcium phosphates in the presence of certain “foreign” ions results in the partial incorporation of these ions in the crystals of the precipitate.