XRF analysis of tooth enamel under conditions of experimental erosion in vitro

INTRODUCTION. Dental erosion is a result of chemical processes – specifically, “acid attacks” on the tooth surface that occur without bacterial involvement – leading to alterations in the mineral structure of dental tissues. In recent years, the erosive potential of fruit juices, carbonated and non-carbonated soft drinks, as well as alcoholic beverages, has been actively studied in an effort to better understand the mechanisms of demineralization and to assess the impact of drink acidity. However, there is a lack of data on experiments that provide a comprehensive profile of macro- and microelement content in erosion zones of varying severity compared to intact enamel and dentin. AIM. To examine, using X-ray fluorescence analysis, the dynamics of changes in the calcium-to-phosphorus (Ca/P) ratio–an important indicator of tooth mineral content–under conditions of artificial erosion caused by various acidic food and beverage solutions. MATERIALS AND METHODS. The exogenous acidic agents used included solutions of lactic, acetic, and hydrochloric acids; lemon juice; dry red wine; Dobry Cola; and a solution of Acidin-Pepsin tablets (a drug prescribed for hypoacid and anacid gastritis). Recently extracted intact teeth were immersed in the test liquids for three days. Demineralization was assessed based on observed changes in elemental composition. The chemical analysis of the solid dental tissues was performed using an M4 TORNADO X-ray fluorescence spectrometer (Bruker). RESULTS. In all test conditions, demineralization occurred as evidenced by the active release of calcium and phosphorus – the main macroelements – from the crystal lattices of hydroxyapatite, carbonate apatite, chlorapatite, fluorapatite, and other mixed apatite forms found in enamel. Notably, the kinetics of calcium and phosphorus loss differed significantly. In all cases, the Ca/P ratio increased substantially after three days of exposure to the erosive medium, compared to baseline values in intact enamel. This finding indicates that phosphate groups are the first to be lost during erosion, dissolving into the oral environment, followed by calcium loss as a less intense secondary process. CONCLUSIONS. Based on analysis of Ca/P ratios, enamel erosion appears to begin with dephosphorylation of the crystalline lattice, followed by decalcification.