Evaluation of enamel demineralization and fluorine uptake caused by gustatory stimulants of salivary secretion (GSSS) using Raman spectroscopy and proton induced gamma-ray emission (PIGE)

In this work, two gustatory stimulants of salivary secretion (GSSS) were studied using Raman microscopy to evaluate their potential demineralization effect in human enamel samples and proton induced gamma-ray emission (PIGE) to quantify fluorine uptake. These pharmaceutical products are usually administrated to patients who have revealed xerostomia, namely, caused by radiation therapy, chemotherapy, or diseases such as Sjögren's Syndrome. Traditional GSSS are composed of citric or malic acids that can promote enamel erosion by decreasing salivary pH below the critical level of hydroxyapatite demineralization (pH = 5.5). Recently, new GSSS composed of malic acid, fluorine, and xylitol were developed, which are supposed to decrease erosion potential risk and uptake fluorine in dental enamel. In this, in vitro study, 16 specimens of human enamel were randomized in two different groups exposed to two different GSSS: S group—SST® (with citric and malic acids, without fluorine) and X group—Xeros™ (with malic acid, fluorine, and xylitol) and analysed before and after treatment. The treatment simulated administration of four tablets per day during eight consecutive days. Statistically, significant increase in fluorine concentration was found in samples treated by Xeros™, whereas no significant differences were found in fluorine concentration for the ones treated using SST® treatment. No demineralization was found in dental enamel samples treated with either Xeros™ or SST®.