Introduction : Email is the hardest layer on the tooth crown. The enamel-forming minerals can be detached from the tooth surface called demineralization. Demineralization occurs when the pH of the oral cavity is below the enamel critical pH limit of 5.5.Objective : find out whether there was an effect of UHT milk and Pasteurized milk on enamel surface hardness.Methods: Thirty crowns of maxillar…