sepharose and Dental-Caries

A novel biomimetic mineralization system was designed to induce a layer of hydroxyapatite on a demineralized dentin surface. This system was constructed as follows. A layer of 0.5% agarose gel containing 0.26M Na(2) HPO(4) was used to cover acid-etched dentin slices, followed by a layer of agarose gel without phosphate ions. Then a neutral 0.13M CaCl(2) solution was added onto the ion-free gel surface. The mineralization system (dentin-agarose gel containing phosphate ions-CaCl(2) solution) was kept in a water bath at 37°C, and the gel and CaCl(2) solution were replaced at various intervals. The results showed that the deposited hydroxyapatite crystals densely packed to each other, completely covered the dentin surface, and occluded the dentinal tubules after 10 days of biomimetic mineralization in vitro. Therefore, this method may provide the experimental basis for dentin remineralization and for a new method to treat dentin hypersensitivity and dental caries.

Topics: Biomimetic Materials; Dental Caries; Dentin; Dentin Sensitivity; Durapatite; Gels; Humans; Sepharose

The uptake of calcium by a polysaccharide (agarose) gel used as a model for plaque from a two-step treatment (consisting of a calcium rinse followed by a fluoride treatment) and the effect of the deposited calcium in model plaque on caries lesion formation in enamel were determined. Calcium uptake was measured by treatment of the model plaques with [45Ca]-CaCl2 solutions with or without NaF. A two-step treatment consisting of calcium followed by fluoride produced a 100% increase in calcium content of model plaque, presumably due to the formation of CaF2, compared with a treatment with artificial saliva followed by calcium alone. The effects of these increased plaque minerals on caries lesion formation were studied by subjecting model-plaque-covered enamel blocks to a cyclic demineralization-remineralization treatment. Artificial-plaque-covered enamel blocks were treated daily with 180 ppm calcium for ten min, then 100 ppm fluoride for ten min, followed by demineralization for 16 h, and finally, remineralization for seven h and 40 min. After five days, the blocks were sectioned, and lesion formation was determined by microradiography-microdensitometry. Artificial plaque treated with a calcium rinse followed by a fluoride rinse reduced lesion size by 90%, compared with a 68% reduction by a fluoride rinse alone. When the experiment was repeated with a simulated pre-brush calcium rinse (180 ppm calcium) followed by a fluoride dentifrice suspension (110 ppm fluoride), lesion size was reduced by 46%, compared with a 32% reduction by the fluoride dentifrice suspension alone.

Topics: Absorptiometry, Photon; Calcium; Cariostatic Agents; Dental Caries; Dental Enamel; Dental Plaque; Fluorides; Humans; Lactates; Lactic Acid; Models, Biological; Mouthwashes; Placebos; Saliva, Artificial; Sepharose; Tooth Remineralization; Toothpastes