Sterrett J D, Bankey T, Murphy H J
Division of Periodontics, Faculty of Dentistry, University of Halifax, Nova Scotia, Canada.
J Clin Periodontol. 1993 May;20(5):366-70. doi: 10.1111/j.1600-051x.1993.tb00374.x.
Preliminary work has shown that the rate of dentin demineralization increases with increasing concentrations of citric acid. This rate subsequently diminishes at much higher concentrations. The purpose of this study was to more precisely identify the citric acid concentration which produces peak dentin demineralization and to determine if this demineralization process is time dependent. Flat dentin surfaces were prepared on the buccal and lingual sides of 15 bovine molars. 8 depressions were made in each dentin surface using a #8 round bur in a high-speed handpiece with air-water coolant. Various concentrations of citric acid solutions (weight per cent) were prepared, e.g., 0%, 10%, 20%, 25%, 30%, 35%, 40%, 65% and their respective pH's recorded. 3 microliters of each citric acid solution were placed in individual depressions on the dentin surfaces and left undisturbed for 1, 2 or 3 min. Cotton pellets were used to soak up the citric acid solution, along with any dissolved calcium, and were subsequently placed in 10 ml of 18 Me omega water. The parts per million calcium found in each water sample were determined using atomic absorption spectrophotometry. Peak dentin demineralization for 1-, 2- and 3-min application times occurred at 30% (pH = 1.55), 25% (pH = 1.62) and 25% (pH = 1.62) citric acid concentrations/(pH), respectively. Dentin demineralization was found to be time-dependent for all citric acid solution concentrations. The clinical significance of these findings is discussed.
前期工作表明，随着柠檬酸浓度的增加，牙本质脱矿率上升。但在更高浓度时，该速率随后会降低。本研究的目的是更精确地确定产生牙本质脱矿峰值的柠檬酸浓度，并确定这种脱矿过程是否与时间有关。在15颗牛磨牙的颊侧和舌侧制备平坦的牙本质表面。使用配备空气 - 水冷却剂的高速手机中的8号圆钻在每个牙本质表面制作8个凹坑。制备了各种浓度的柠檬酸溶液（重量百分比），例如0%、10%、20%、25%、30%、35%、40%、65%，并记录其各自的pH值。将3微升每种柠檬酸溶液放置在牙本质表面的各个凹坑中，静置1、2或3分钟。用棉球吸干柠檬酸溶液以及任何溶解的钙，随后将其置于10毫升18兆欧水中。使用原子吸收分光光度法测定每个水样中钙的百万分率。在1分钟、2分钟和3分钟的作用时间下，牙本质脱矿峰值分别出现在30%（pH = 1.55）、25%（pH = 1.62）和25%（pH = 1.62）的柠檬酸浓度/（pH）下。发现对于所有柠檬酸溶液浓度，牙本质脱矿都与时间有关。讨论了这些发现的临床意义。
