The study of infiltration and microabrasion effects on the tooth surface structure on chemical model of focal enamel demineralization

Abstract

Objective: to create in vitro model of local enamel demineralization (LED) and to compare the morphological changes in the enamel microstructure after infiltration and microabrasion treatment. Materials and methods. A solution of hydrochloric acid in decreasing concentrations was used to create LED model: 0.3% HCl for 48 hours, 0.15% HCl for 120 hours, 0.1% HCl for 48 hours and 0.05% HCl for 96 hours at room temperature. Using scanning electron microscopy (SEM), we studied a microstructure of the surface and sagittal sections of intact teeth, as well as teeth with artificial LED before and after treatment by infiltration and microabrasion. Results. The tooth surface in the artificial LED zone is characterized by areas with partially and completely demineralized interprismatic substrate. In the partially demineralized zone, channels are formed after dissolution of the enamel prisms structure. In zones with complete demineralization of the crystalline structure, the organic matrices looks like a smooth surface. After microabrasion, the tooth surface represents an even prism layer with prism sheaths forming arcuate excavations. Infiltration of the LED region modifies the tooth surface into a flat field without pores and microcracks, completely covering the lesion with an infiltrant. Conclusion. The proposed method of enamel processing with hydrochloric acid solutions of a decreasing concentration allows LED formation within enamel layer for teeth with various caries resistance. According to SEM data, LED treatment by microabrasion and infiltration effectively smoothes the tooth surface and eliminates defects. After microabrasion, excavations in the area of enamel prism sheaths are preserved on the surface.