<prompt> The minimum amount of tooth demineralization required for radiographic detection of dental caries is20406080  <response>: Lesions confined to enamel may not be evident until approximately 30 to 40 demineralization has occurred. For this reason, the actual depth of penetration of a carious lesion is often deeper than seen in the image. Oral radiology by White Pharaoh 7th ed. Page no 288 