Characterization and Application of Bioactive Glass and Chitosan Nanoparticles for Tooth Enamel Remineralization

Abstract

We investigated the remineralization of demineralized enamel surfaces through the application of bioactive glass (BG) and chitosan nanoparticles (CNPs). BG and CNPs were immersed in artificial saliva for 7 days. The resulting crystals were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Embedded enamel blocks were immersed in demineralization solution and then classified into five treatment groups: (1) No material applied; (2) toothpaste containing NaF (F); (3) CNP hydrogel; (4) distilled water slurry containing BG; and (5) CNP hydrogel containing BG (BG-CNP). The enamel blocks were immersed in an artificial saliva solution for 1 month; each material was applied twice per day. Nanoindentation testing of enamel surfaces was performed during the immersion period. We found that unidirectional rod-shaped crystals formed in the artificial saliva solutions treated with BG and BG-CNP, showing multiple XRD peaks for hydroxyapatite. The mechanical properties of enamel surfaces decreased markedly following immersion in the demineralization solution, and significantly recovered after 1 month of BG-CNP and BG treatment compared to other the specimens. Porous demineralized enamel surfaces were filled with a remineralization layer after immersion in saliva and application of NaF, BG, and CNP-BG. Thus, daily application of CNP-BG or BG facilitates enamel remineralization.