Abstract
The concentration of calcium, phosphate and hydroxyde in a solution affects the degree of saturation with respect to the enamel. The effect of calcium concentration in preventing enamel demineralization was investigated in this study. Three thin sections,140μm to 160μm thick, were cut out from each of nine human premolars. All surfaces of the sections, except for the original enamel surface, were coated with nail vanish. These sections were immersed in demineralizing solutions for one week at 25°C.
The compositions of the solution was 0.1 mol/L lactic acid,23 mmol/L monobasic potassium phosphate,3 mmol/L sodium azide and the pH value was 4.4. The concentration of calcium chloride was 7,14 or 21 mmol/L in the three solutions. After 1 week, the degree of demineralization was determined by image analysis of contact micro-radiograms from each section. A big sub-surface lesion was observed in the solution with 7 mM calcium. The area of the subsurface lesion decreased in accordance with the increase of calcium concentration from 7 mM to 14 mM. The calcium concentration of 21 mM in the solution caused almost no demineralization in the enamel. The results revealed that increase of calcium concentration alone can prevent enamel demineralization even though other conditions such as pH were exactly the same.
