In order to examine and contrast the effects of brushing with miswak and nano calcium carbonate toothpaste on the surface hardness of human teeth surfaces that had been demineralized with citric acid, a study was conducted. Surface hardness was assessed using a Knoop Hardness Tester after brushing for fourteen or twenty-eight minutes, and data were compared using Wilcoxon, Kruskal-Wallis, and Mann-Whitney tests. These findings demonstrated that the increase in surface hardness following the use of nano calcium carbonate toothpaste was greater than the rise following the use of miswak toothpaste (p 0.05).