Effect of surfactant on fluoride uptake to the acid treated enamel
2002 Volume 65 Issue 1 Pages 106-120
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2002 Volume 65 Issue 1 Pages 106-120
I evaluated the effect of fluoride dentifrice on the surface of acid treated enamel. Enamel specimens 3 millimeters in diameter were prepared using a diamond core drill from extracted human incisors that were caries free and showed no signs of decalcification. The surfaces of the samples were highly polished using standard methods and immersed in 0.1 M HCl for 5 minutes at room temperature. The acid etched enamel specimens were treated for 5 minutes with either NaF solution (250 ppmF), NaF solution containing surfactant (sodium lauryl sulfate: SDS) or NaF-dentifrice solution for 5 minutes. The SDS concentrations were 0.1, 0.25, 0.5, 0.75 or 1.0%. The treatment was repeated 7 times at 24 hour intervals. Distilled water was used as a control.
The atomic force microscopy (AFM) observation indicated that the surface of the controls disappeared with acid treatment and the top of the enamel rods became flat. Fluoride reaction products from the NaF solution were observed on top of the enamel rods. However, when the SDS concentration was over 0.75%, when NaF dentifrice treatment was done, fluoride reaction products appeared at the bottom of the enamel rods inter space. Enamel crystals were larger than those in the controls for the enamels treated by immersion in SDS NaF solution and in NaF-dentifrice. The X-ray photoelectron spectroscopy (ESCA) analysis indicated that the F/Ca atomic ratio after treatment with NaF solution decreased from 0.23 at the surface to 0.06 in the 10^<th> layer. however, the ratio was almost the same for treatment with SDS･NaF solution or NaF-dentifrice. Fluoride uptake was less when the SDS concentration under 0.5%. However, when the SDS concentration was over 0.75% or when treatment was with NaF dentifrice, there was more of fluoride uptake at the 10^<th> layer than in other layers.
I concluded that surfactant treatment spread the fluoride ion uptake into enamel rod inter space and promote crystal growth of enamel. Shika Igaku (J Osaka Odontol Soc) 2002 Mar; 65(1): 106-120.
