Fluoride, Calcium and Phosphorus Uptake by Dentin from a Resin Modified Glass Ionomer-based Material for Dentin Hypersensitivity Treatment

Abstract

The purpose of this study was to analyze the uptake of fluoride (F), calcium (Ca) and phosphorus (P) by dentin from a newly developed resin-modifier glass-ionomer liner for dentin hypersensitivity treatment (Clinpro™ XT varnish; Clinpro). A standardized box-form cavity (3mm in width and 1.5mm in depth) was prepared in the buccal cervical area of 20 intact human premolars and was filled with Clinpro. The specimens were immersed in distilled water at 37℃ for 1, 7, 30 and 90 days (n=5, each), and then sectioned longitudinally in a bucco-lingual direction through the center of the cavity. Elemental compositional analysis and elemental mapping of the material-dentin interfacial layer was carried out by wavelength-dispersive X-ray spectroscopy electron-probe microanalysis. Set Clinpro specimens without water immersion and dentin specimens without Clinpro filling served as controls. After 90 days of water immersion, relative density of F, Ca and P increased in dentin but decreased in Clinpro along the Clinpro-dentin interface (5-20μm apart from the interface). An increase of Ca/P ratio in the interfacial dentin was also detected. Elemental mapping revealed a layer of high F concentration in the interfacial dentin, and its width gradually increased with longer immersion time. These results demonstrate that Clinpro has the capacity to release F, Ca and P and suggest that this capacity may contribute to the control of dentin hypersensitivity and provide a cariostatic effect on this material.