Remineralizing Efficacy of Fluorohydroxyapatite Gel on Artificial Dentinal Caries Lesion

Abstract

The aim was to evaluate the remineralizing efficacy of fluorohydroxyapatite (FHA) gel on artificial dentinal caries lesion in vitro. Artificial carious lesions were made on occlusal cavities of teeth by exposing the dentin surface to a demineralizing solution. Each cavity was capped with a 3 mm thick FHA gel for 4 weeks. After the FHA gel was removed, the surface morphology and structure of the dentin were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR). The dentin mineral density (DMD) was measured by micro-computed tomography (Micro-CT). A layer of dense and orderly hexagonal crystal structure, with average diameter of 1 m and thickness of 45 m, could be observed on dentin surface. These crystals exhibited elemental peaks for calcium, phosphorus, carbon, and oxygen and characteristic peaks of hydroxyapatite (HA) and fluorapatite (FA) via XRD and FT-IR. The DMD of dentin surface layer significantly increased after it was capped with FHA gel (P<0.05). In the present study, the FHA gel could rapidly construct apatite on the artificial dentin caries surface and significantly increase the mineral density, which suggests that FHA gel might be a proper IPT material with remineralizing function.