�ber den anorganischen Aufbau der Z�hne

Apatites deficient in divalent cations

“…2 Th erc are t wo conflicting explanation s for a low Ca/P 1'a t io in ccrtain h igll-surface-area h.Hlr oxyapatites . T he first states t hat an excess of phosphate ions is adsorbed on the su rface of t iny crystals of s toichiom etri c h yd roxyapatite [3,4] . .…”

Biochemical and Nutritional Studies in Relation to the Teeth

“…Indeed, it has been observed (37,38,40,41) that the diffraction patterns and lattice constants of tooth substance more closely match those of hydroxyapa tite than those of other members of the apatite group of minerals. It appears certain, therefore, that the fundamental crystal structure, of at least the predominant part of the mineral phase of calcified tissues, is that of an apatite.…”

“…Enamel then would differ from dentin only by having a smaller amount of carbonate around, and in association wi:h, the particles of hydroxy apatite. These workers also indicate, especially in the case of dentin, that phosphate ions are adsorbed to minute hydroxyapatite crystals since some specimens of dentin on heating at 900° change their x-ray diffraction patterns (38,40) to one resembling that exhibited, after ignition, by hydroxyapatite bearing adsorbed phosphate (48). The postulate that some phosphate is adsorbed as phosphate ions reduces the calculated amount of calcium required for the apatit e structure, and makes up for the calcium deficit that otherwise would occur as a consequence of the existence of some of the alkali element as carbonate outside of the apatite molecule.…”

“…Hodge and co-workers (10,38,39) and Bale (40) prefer the view that carbonate <tpatites do not occur in calcified tissues, and that the sole apatite present in these substances is hydroxyapatite with "oc cluded, adsorbed, or interstitially crystallized carbonates." Enamel then would differ from dentin only by having a smaller amount of carbonate around, and in association wi:h, the particles of hydroxy apatite.…”

The Basic Calcium Phosphates and Related Systems. Some Theoretical and Practical Aspects.

“…were in good agreement with the results of previous workers (38,39), his conclusions on the basic region were quite different. Whereas Cameron and his associates had given up the idea that tricalcium phosphate could be produced in an aqueous system in stable or metastable7 8 form and had decided instead that dicalcium phosphate and lime formed a continuous series of solid solutions,9 Bassett believed that the data showed the existence of triand tetra-calcium phosphates. He based his conclusion 7 The terms "tricalcium phosphate" and "hydroxyapatite" are very widely and very loosely used.…”