In vivo Remineralization of Plaque-Induced Initial Enamel Lesions – A Microradiographic Investigation

Shallow initial enamel lesions approximately 50 μm in depth were experimentally induced by plaque in sound intact human enamel. The lesions were subsequently remineralized in vivo without any fluoride treatment for periods of 1.5 and 3 months, respectively. 11 participants carried enamel blocks in a dental appliance. To induce demineralization the enamel was placed in a well about 1.5 mm under the polymer surface to facilitate the accumulation of cariogenic plaque. In the remineralizing stages each participant remineralized the lesions previously induced in his own oral cavity as well as specimens demineralized by other participants. For remineralization the enamel was placed flush with the polymer surface of the appliance. The results were evaluated by means of microradiography and showed that after 6 weeks the mean lesion depth was 47 ± 2 μm while the mineral loss ΔZ was 1,284 ± 513 vol% × μm. After 6 weeks of remineralization about 80% of the specimens remineralized significantly; however, 20% continued to demineralize. The results suggest that natural remineralization is more dependent on a subject's individual oral environment than by the properties of the enamel.