acids formed by bacteria will be neutralized by bicarbonate ions and by the peptide sialin present in salive. pH values below 5 are critical for enamel demineralization.If there is frequent exposure to sugar,the rate of demineralization of the tooth will exceed that of remineralization and caries will occur. If exposure to sugar is limited, the rate of remineralization of the tooth will exceed that of demineralization and caries development will be arrested.