Comparative Study of Diode Laser Enhanced Remineralization by Fluoride and Nanohydroxyapatite of the demineralized human enamel

Abstract

Introduction: Remineralization of the initial enamel lesions is an important preventive procedure that applies several agents and techniques. Many remineralizing agents and techniques have been reported, and there is controversy about the optimum procedures. Fluoride is considered a gold standard in remineralization, but its limitations necessitated the innovation of new agents.Aim of the Work: The present study aims to compare the effect fluoride versus nanohydroxyapatite on enamel remineralization enhanced by a diode laser.Materials and Methods: Eight enamel samples of human premolars were subjected to hydrochloric acid demineralization, followed by laser application. The samples were equally divided into two subgroups, one subjected to fluoride and the other subjected to nanohydroxy apatite toothpaste. The assessment was done by scanning electron microscope, energy dispersive X-ray Analysis, and Micro Vickers Hardness Tester before and after demineralization; and also after remineralization. The outcomes of samples in each stage were considered as a separate group.Results: Demineralizing solution caused observable defective enamel surface and significantly decreased microhardness and calcium weight percentage. The remineralization by nanohydroxyapatite revealed a smooth enamel surface with minimal defects by scanning electron microscope more than fluoride, which showed a remineralized enamel surface alternating with areas of erosive defects. nanohydroxyapatite caused enhanced calcium repair by energy dispersive X-ray Analysis more than fluoride. Buccal enamel surface microhardness was more improved in the fluoride-treated samples than in those treated with nanohydroxyapatite. The results were statistically significant in the calcium wt % changes and the microhardness (p-value <0.05).Conclusions: Each of nanohydroxyapatite and fluoride sufficiently protected the enamel surface. The chemical composition of enamel was more improved by nanohydroxyapatite. While the microhardness was more enhanced by fluoride.