Remineralization Effect of Eggshell versus Nano-hydroxyapatite on Caries-like Lesions in Permanent Teeth (In Vitro)

Background: Eggshell (ES) is a rich source of minerals since it contains calcium, phosphorous, magnesium, strontium, and fluoride. This study sought to compare the efficacy of nanohydroxyapatite (NHA) and ES for remineralization of enamel caries-like lesions by pH cycling. Materials and Methods: In this in vitro experimental study, artificial enamel carious lesions were induced in 47 human teeth using an acidic buffer solution. Deionized water was used as the control group, and 10% NHA and 3% and 10% ES powders in deionized water were tested as therapeutic agents. The surface microhardness of the samples was measured by a Vickers hardness tester before and after demineralization and after the application of therapeutic agents in a 7-day pH-cycling model. The data were analyzed using repeated measures analysis of variance. Results: Microhardness significantly decreased in all samples after demineralization and significantly increased after exposure to therapeutic solutions. Microhardness of the samples was not significantly different among the therapeutic groups after pH