The starting phase on early childhood caries or circular caries is an initial lesion, known as macula Alba or white spot, which is reversible, stops or reverses (perform biological repairs). In the initial lesion stage (macula alba) with the removal of caries the causative agent (dental plaque) on the one hand, and taking maximum preventive measures on the other hand: proper nutrition of the young child, salivation with normal pH and saliva composition, adequate mechanical and chemical control of dental plaque, by maintaining proper oral hygiene and topical application of fluoride preparations in various forms, conditions are created for the predominance of remineralization processes in relation to demineralization, which compensates for the insufficiency of minerals and may lead to the disappearance of the initial lesion (restutio ad integrum). Purpose of the Study investigation: Evaluation of ultra-structural enamel changes in the enamel in the starting phase on initial lesion of circular caries - Early childhood caries. It is done with Scanning Electronic Microscope (SEM) evaluation of remineralizing effects in enamel ultrastructure at the stage of initial lesion and superficial form, after topical application of fluoride-based preparation (p-p amino fluoride). Material and method: The investigation was done on laboratory tests on extracted 20 healthy lower incisions and two more groups with 10 upper incisions, where some have topical fluoride compression treatment with SEM (Scanning Electron Microscope), and the others did not have the treatment. After that, we have analysis of the remineralizing effect of fluorides with SEM photo attachments. Results: In some dental samples we managed to get almost healthy enamel, i.e. complete remineralization process of the inicial lesion. Conclusion: Once again, we have confirmation of one of the many benefits of fluoride in dentistry which is long been known.