Surface Characteristics of Hydroxyapatite and Enamel after Adsorption of Fluoride-Containing Macromolecules

Abstract

In this study the adsorption of two fluoride-containing polyelectrolytes with different hydrophobic properties on hydroxyapatite is investigated. It was found that the adsorption of the macromolecule was accompanied by the uptake of fluoride, but at a higher rate and with higher amounts than the polymer itself. The influence of the polyelectrolytes on the surface properties of hydroxyapatite and whole enamel was investigated by zeta potential determinations and contact angle measurements, respectively. It was observed that adsorption of very minor amounts of these macromolecules had a remarkable effect on the zeta potential of hydroxyapatite. The original zeta potential of ––9 mV was increased to relatively high positive values. Furthermore, adsorption of the most hydrophobic polymer on the enamel resulted in a poor wettability of the surface by water. Contact angles around 90° were observed, indicating the hydrophobic character of the treated surface.

A Review of Chemical-approach and Ultramorphological Studies on the Development of Fluoride-releasing Dental Adhesives Comprising New Pre-Reacted Glass Ionomer (PRG) Fillers

“…These fillers exhibited extremely high amount of fluoride release, but elution of Na ＋ and F -had a deleterious effect in the breakdown of the integrity of dental materials 17) . In terms of research strategy, previous studies on fluoride release from restorative materials were mostly performed on fluoride-releasing polymers [21][22][23] or glass ionomers 7,8,24,25) . Fluoride release from methacryloyl fluoride-methyl methacrylate (MF-MMA) copolymer was achieved by hydrolysis, followed by an acid anhydride formation 22,23) .…”

“…Consequently, ion-leachable glass fillers have since been incorporated in resin-based restorative materials such as resin-modified GICs, compomers and fluoride-releasing composites, which exhibited varying degrees of fluoride release and recharge 28,29) . Unlike these conventional challeges [21][22][23][24][25][26][27][28][29] , Roberts et al 17) remarked the fact that the fluoride-releasing mechanism of glass-ionomer cement was derived from its acid-base reaction phase, and invented a revolutionary PRG filler technology. PRG fillers were fabricated by the acid-base reaction between fluoridecontaining glass (such as FASG) and polyacrylic acid (such as PAA) in the presence of water to form a wet siliceous hydrogel.…”

“…The 2％ uranyl acetate used had a pH of 4.2, which was similar in acidity to 0.01 mol/L acetic acid (pH=4.0) 82) . Elution of fluoride ions from GICs and compomers was substantially increased in an acidic medium such as acetic acid 21,83) . Moreover, citrate also possesses the ability to form citrate-metal ion complexes that result in hastening the degradation of ion-leachable glass fillers and polysalt matrices in resin-modified GICs and compomers 84) .…”

Water loss at normal enamel histological points during air drying at room temperature

“…In addition, it is known that a negative capillary pressure inversely related to pore diameter exists in nanometric pores, contributing to lower water motility in intraprismatic pores compared to the mobility along the prisms sheaths (Tas et al, 2003). When the possibility that fluoride is able to reduce capillary force, by creating a less steep zeta potential (Bartels et al, 1982), the effect of pore size still contributes to a higher capillary force in the intraprismatic pores.…”

X-Ray Diffraction Studies on the Thermal Stability of Calcium-Strontium Hydroxyapatite Solid Solutions Syntheszed in the Presence of Diethylamine

“…The synthesis and isomorphous substitution reactions of HAP have been widely investigated by several researchers. (Baud et al, 1973;Kousoukos and Nancolas, 1981; Bartels et al, 1982;Thomas et al, 1989;Inikori, 1991;Ajibola, 1995). During investigations of cationexchange characteristics of various synthetic HAP it has been discovered that cations having ionic radii close to that of calcium tend to replace Ca 2+ in the apatite structure (Patel,1979;Young,1980;Thomas et al, 1989;Inikori, 1991;Ajibola, 1995).…”