title: Chemical and crystallographic events in the caries process.
abstract: The chemical and crystallographic events associated with the caries process can be described based on the results from the following studies: (a) effects of carbonate, magnesium, fluoride, and strontium on the physico-chemical properties--lattice parameters, crystallinity (crystal size and strain); dissolution properties of synthetic apatites; (b) factors influencing the in vitro formation and transformation of DCPD, OCP, AP (Ca-deficient apatites), FAP, beta-TCMP (Mg-substituted), and CaF2; and (c) studies on properties (crystallinity, composition, chemical, and thermal stabilities) of enamel, dentin, and bone. The dissolution of CO3-rich/Mg-rich/F-poor dental apatite crystals and re-precipitation of CO3-poor/Mg-poor/F-rich apatite in the presence of F- ions in solution contribute to a more acid-resistant surface layer of the caries lesion. Fluoride promotes the formation of less Ca-deficient and more stable apatite crystals. The presence of Ca, P, and F in solution inhibits dissolution of apatite more than does the presence of F alone. Low levels of F in solution promote the formation of (F, OH)-apatite, even under very acid conditions; an increase in F levels causes the formation of CaF2 at the expense of DCPD or apatite, especially in acid conditions. F in apatite and/or in solution suppresses extensive dissolution of dental apatite and enhances the formation of (F, OH)-apatite crystals which are more resistant against acid-dissolution than are F-free apatite crystals.
authors.affiliation: New York University College of Dentistry, New York 10010.
authors.forename: R Z
authors.initials: RZ
authors.lastname: LeGeros
mesh_terms: D001031:Apatites / Q000138:chemical synthesis; D002130:Calcium Phosphates / Q000138:chemical synthesis; D003460:Crystallization; D003731:Dental Caries / Q000378:metabolism*; D003739:Dental Cementum / Q000032:analysis*; D003743:Dental Enamel / Q000032:analysis*; D003804:Dentin / Q000032:analysis*
chemical_list: D001031:Apatites; D002130:Calcium Phosphates