Kinetics and surface energy approaches to the crystallization of syntheticand biological calcium phosphates

Constant composition methods have been used to investigate the mechanisms o f crystal growth and dissolution of synthetic and biological calcium phosph ates. Interfacial tensions between water and each of these surfaces were ca lculated from measured contact angles using surface tension component theor y. The data, 4.5 x 10(-3), 8.8 x 10(-3) and 10.4 x 10(-3) J m(-2) for human dentin, human enamel and hydroxyapatite, respectively, compared well with the data calculated from dissolution kinetics experiments and provided info rmation concerning the growth and dissolution mechanisms. The ability of a surface to nucleate other phases is closely related to the magnitude of the interfacial energies.