Amount of Calcium Elution and Eroded Lesion Depth in Bovine Enamel Derived from Single Short Time Immersion in Carbonated Soft Drink <i>in Vitro</i>

Abstract

Erosion is one of serious oral health problems among Japanese children. Some dentists argue that brushing just after food/drink intake induces enamel abrasion. Objectives of this study were to evaluate amount of calcium elution from bovine enamel due to single and short immersion into carbonated soft drink, to calculate depth of the eroded lesion, and to determine when to brush teeth after carbonated soft drink intake from the view point of preventing enamel abrasion. Four enamel specimens were made from each of eight bovine teeth. The specimens were covered by quick-cure resin except for enamel surfaces. The four specimens from each bovine tooth were classified into three, six, nine, and 12 minutes immersion (IM3, IM6, IM9, and IM12) groups and immersed separately in five mL of carbonated soft drink. After the immersion, the calcium concentration of the original drink and the drink samples were evaluated using atomic absorption spectrophotometry. The dimension of each enamel specimen was calculated using a planimeter. The amount of eluted calcium per unit area of the enamel specimen into each drink sample was obtained. The depth of the demineralized lesion was obtained by dividing the amount of calcium elution per unit area by the concentration of calcium in enamel and the specific gravity of enamel. The lesion depth of the IM3 group was significantly lower than those in the IM6, IM9, and IM12 groups. The mean lesion depth in the IM12 group which showed the deepest lesion depth was 0.21 μm. As conclusions, the erosive lesion depth due to intake of carbonated soft drink was much shallower than remineralized enamel surface of a white spot lesion which can be repaired in plaque fluid in a short time, suggesting such erosion hardly causes tooth wear, hence it was suggested that brushing teeth just after the intake was recommended.