Bashir E, Ekberg O, Lagerlöf F
Division of Cariology, Center for Clinical Oral Science, Huddinge, Sweden.
J Dent. 1995 Aug;23(4):209-12. doi: 10.1016/0300-5712(95)91184-o.
Citric acid clearance from the oral cavity may be an important factor in the erosion of dental enamel. The aim of the present study was to investigate the clearance pattern of citric acid in normal subjects.
After determination of the unstimulated salivary flow rate and the residual volume of saliva after normal swallowing, 12 subjects rinsed with 95.2 mmol l-1 citric acid for 5 s. At 1, 2, 5, 10 and 15 min after the rinse a small saliva sample was collected and the concentration of citric acid was determined enzymatically. For each subject three separate experiments on different occasions were performed with a citric acid solution of pH 2.1 and one experiment with a solution of pH 4.5.
The salivary citric acid concentration declined biphasically: rapidly during the first 2 min, then more slowly. The elimination rate over the first minute was on average 87.7 mmol l-1 min-1 at pH 2.1 compared with 85.0 mmol l-1 min-1 at pH 4.5. The difference between individuals estimated from the areas under the clearance curve was strongly significant (P < 0.001). No significant relation was found neither between salivary flow rate and clearance, nor between residual volume after swallowing and clearance.
The clearance pattern of citric acid is an individual property.
口腔中柠檬酸的清除可能是牙釉质侵蚀的一个重要因素。本研究的目的是调查正常受试者中柠檬酸的清除模式。
在测定非刺激性唾液流速和正常吞咽后唾液残留量后，12名受试者用95.2 mmol l-1的柠檬酸漱口5秒。在漱口后1、2、5、10和15分钟收集少量唾液样本，并通过酶法测定柠檬酸浓度。对每名受试者在不同时间进行三次单独实验，使用pH值为2.1的柠檬酸溶液，以及一次使用pH值为4.5溶液的实验。
唾液中柠檬酸浓度呈双相下降：在最初2分钟内迅速下降，然后下降速度减慢。在pH值为2.1时，第一分钟的消除率平均为87.7 mmol l-1 min-1，而在pH值为4.5时为85.0 mmol l-1 min-1。根据清除曲线下面积估计的个体间差异非常显著（P < 0.001）。在唾液流速与清除率之间，以及吞咽后残留量与清除率之间均未发现显著关系。
柠檬酸的清除模式是个体特有的属性。
