Alternating Demineralization and Remineralization of Artificial Enamel Lesions

Mineral loss and uptake in artificial enamel lesions was investigated by pH cycling: samples were subjected to a sequence of de- and remineralizing solutions. The ratio between de- and remineralization per day and the presence of fluoride in the remineralizing solution were varied among different experimental groups. Calcium, phosphate and fluoride uptake and loss were measured. The lesions were also studied with a hardness tester and micro radiography. The results show a difference in remineralization mechanism between continuously remineralized and pH-cycled samples (with respect to Ca/P ratios). With fluoride present, after some time, ‘arrested’ carious lesions are formed, which can hardly be further demineralized or remineralized. This is in agreement with clinical findings of remineralization in areas with fluoridation of the drinking water.