Enamel apatite parameters

Le Geros RZ (1965) Effect of carbonate on the lattice parameters of apatite. Nature 206 403-404 Le Geros RZ, Miravite MA, Quirolgico GB, Curzon ME (1977) The effect of some trace elements on the lattice parameters of human and synthetic bone. Calc Tiss Res 22 362-367 Le Geros RZ, Bond B, Le Geros R (1978) Types of H2O in human enamel and in precipitated apatites. CalcifTiss Inti 26 111-118... 

Substitutions in the HA structure are possible. Substitutions for Ca, PO4, and OH groups result in changes in the lattice parameter as well as changes in some of the properties of the crystal, such as solubility. If the OH" groups in HA are replaced by F" the anions are closer to the neighboring Ca " ions. This substitution helps to further stabilize the structure and is proposed as one of the reasons that fluoridation helps reduce tooth decay as shown by the study of the incorporation of F into HA and its effect on solubility. Biological apatites, which are the mineral phases of bone, enamel, and dentin, are usually referred to as HA. Actually, they differ from pme HA in stoichiometry, composition, and crystallinity, as well as in other physical and mechanical properties, as shown in Table 35.7. Biological apatites are usually Ca deficient and are always carbonate substituted (COs) " for (P04). For... 

Table A3.6 Crystallite Size and Lattice Parameters of the Apatite in Human Enamel and Dentin ...

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