Interactions between fluoride and plaque in the remineralization of enamel caries-like lesions

The effect of fluoride and plaque, separately and together on the remineralization of early artificial caries lesions was studied in a group of volunteers in a double-blind randomized study design. Artificial caries lesions produced in slabs of human enamel were mounted buccally in silver bands cemented bilaterally to the mandibular first molar teeth. Volunteers wore the bands for two 2-week periods, rinsing daily with either a placebo or a 500 ppm fluoride mouthrinse. Plaque accumulation was encouraged by placing Dacron gauze over one of each pair of slabs. Sections were cut from the lesions and analyzed by microradiography followed by microdensitometry and image analysis. Microdensitometric data revealed that non-significant increases in mineralization had occurred in all of the test groups. However, the image analysis results indicated that significant remineralization had occurred in lesions after 2 weeks on the fluoride rinse regimen, with no significant remineralization in lesions exposed to the placebo. The presence or absence of plaque over the lesions had no effect on the amount of remineralization induced on the fluoride rinse regimen.