Development of a Method for Testing the Salivary Ability against the Formation of Calcium Phosphate Precipitates

比较了用pH计测定人唾液抗磷酸钙沉淀能力的pH滴法，研究了一种使用pH指示剂溴百里酚蓝（BTB）的简便方法。250 μM NaF的加入扩大了BTB的颜色变化范围。在含250 μM NaF的反应混合物中加入2.5、5.9和7.5% （v/v）的全唾液，37℃孵育40 min后，分别呈现黄色、蓝绿色和蓝色。这表明，用BTB染色法半定量地评价了全唾液对磷酸钙沉淀形成的抑制程度。在实践中，利用10个人的全唾液对磷酸钙沉淀形成的抑制能力进行了评估。pH降法的诱导时间与色标BTB法的pH值的相关系数r较高（0.79 ~ 0.86）。结果表明，人全唾液对口腔钙化（再矿化和牙石形成）的抑制能力可以用BTB方法来评价。

Comparing the pH drop method using a pH meter for human salivary ability against the formation of calcium phosphate precipitates, we studied a convenient method using a pH indicator, bromothymol blue (BTB). The addition of 250 μM NaF widened the range of color change of BTB. The addition of 2.5, 5.9 and 7.5 % (v/v) of whole saliva in the reaction mixture containing 250 μM NaF showed yellow, blue green, and blue, respectively, after incubation at 37℃ for 40 min. This indicated that the grade of inhibition with whole saliva of the formation of calcium phosphate precipitates was semi-quantitatively assessed by the BTB colorization. In practice, the evaluation of inhibitory ability against the formation of calcium phosphate precipitates using 10 individuals' whole saliva was carried out. The correlation coefficient(r) between the induction time (from pH drop method) and the pH value (from BTB method using the color standard) was higher (0.79〜0.86). The result strongly suggests that the inhibitory capability of human whole saliva on oral calcification (re-mineralization and calculus formation) may be easily evaluated by the method using BTB.