THE EFFECT OF THE SUPERSATURATED SOLUTIONS CONTAINING HIGH CONCENTRATIONS OF FLUORIDE ON SEEDED CRYSTAL GROWTH

ABSTRACT 고농도의불소를포함하는과포화용액이apatitic crystal growth에미치는영향 권중원∙금기연∙이승종∙정일영∙이찬영연세대학교치과대학보존학교실 THE EFFECT OF THE SUPERSATURATED SOLUTIONS CONTAININGHIGH CONCENTRATIONS OF FLUORIDE ON SEEDED CRYSTAL GROWTH Jung Won Kwun, Kee-Yeon Kum, Seung-Jong Lee, Il-Young Jung, Chan-Young Lee Department of Conservative Dentistry, College of Dentistry, Yonsei University In biological systems, the mineral that forms hard tissue is of an apatitic nature, and hydroxya-patite(Ca 5 OH(PO 4 ) 3 : HA) is generally considered as the prototype for such a miner al. Thus, the precipita-tion of HA, having biological implications, has been the subject of several investigations.Crystal growth studies using HA seeds in supersaturated solutions have enhanced our understanding ofthe process and mechanism involved in seeded crystal growth. From these studies, it has become apparentthat the precipitation rate of HA onto the seed crystals depends on the various conditions, especially on theadditives.The relation between the supersaturated solution containing fluoride and the process of HA crystalgrowth enhances the understanding of mechanism of HA crystal growth.Until recently, the studies have been on the crystal growth of enamel minerals and synthetic HA seeds inthe supersaturated solution containing 1�2 ppm fluoride. The purpose of the present investigation is to study the effect that fluoride of high concentration has onthe crystal growth kinetics of HA.In order to produce the composition found in the secretory enamel fluid, experimental solutions of 1mMCa, 3mM P, and 100mM Tris as background electrolyte were used. Then this experimental solutions wereadded to 0, 2, 4, 6, 8, 10 ppm fluoride.The effect of fluoride at high concentrations on the precipitation was examined in a bench-top crystalgrowth model adopting a miniaturized reaction column. Chemical analysis was employed for characteriza-tion of working solutions before and after the experimentation.Remarkable findings were : 1) the amount of crystal growth was gradually accelerated as the fluorideconcentration increased until 6 ppm, but decreased in 8 and 10 ppm fluoride; 2) the amount of fluoride ionconsumed in crystal formation was constant despite the increase in fluoride concentration.