Thisdifference between the Mutans group and Sobrinus group was signifcant stayistically. Effect of measurement of hardness in enamel surface showed clea in the Mutuans group decreased by 35%and sobinus group by45%.

• 结果 变形链球菌和远缘链球菌均可使牙釉质表面显微硬度下降 ,下降率分别为 35%25和 4 5%25 ,且远缘链球菌组随时间下降高于变形链球菌。