Demineralization starts at the enamel surface as it is the most mineralized tissue of the tooth White-spot lesions are the earliest macroscopic evidence of caries particularly enamel caries. The majority of demineralization in white-spot lesions occurs in the subsurface region of enamel.Typically the enamel surface layer stays intact during subsurface demineralization, but if no treatment is done at that stage it eventually collapse into a cavitated lesion which reduces the chances of remineralization drastically.Thus early diagnosis of dental caries is of paramount important. If we are able to intercept caries lesion at subsurface level with the help of remineralizing agents, we can actually achieve a caries free mouth.