Aiuchi H, Kitasako Y, Fukuda Y, Nakashima S, Burrow M F, Tagami J
Department of Restorative Sciences, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan.
Aust Dent J. 2008 Jun;53(2):167-71. doi: 10.1111/j.1834-7819.2008.00027.x.
The ion activity product for hydroxyapatite (Ip(HA)) is a comprehensive parameter reflecting pH, calcium and phosphate ion concentration in saliva which govern the degree of saturation with respect to the dissolving tooth mineral. The aim of this study was to evaluate the relationship between quantitative assessments of salivary buffering capacity and Ip(HA) in relation to cariogenic potential.
Stimulated whole saliva was collected from 33 patients, and the initial pH of samples was measured using a hand-held pH meter. Then samples were titrated with 0.1 N HCl to evaluate buffering capacities and divided into three groups (high, medium and low). After measuring concentrations of calcium and phosphate ions in the samples, Ip(HA) was calculated using the values of the ion concentrations and pH. Differences in the mean pH values, the concentrations of calcium, phosphate ions and log[Ip(HA)] among three groups were analysed using the Kruskal Wallis and the Mann-Whitney non-parametric test, p < 0.05.
After HCl 50 microL titration, there were statistical differences of the mean pH and Ip(HA) among each buffering capacity group. Moreover, after 50 microL HCl titration, there was an excellent correlation between the buffer capacity and log[Ip(HA)].
The pH change for saliva after HCl titration has a significant influence on the rate of Ip(HA).
羟基磷灰石的离子活性产物（Ip(HA)）是一个综合参数，反映了唾液中的pH值、钙和磷酸盐离子浓度，这些因素决定了牙齿矿物质溶解的饱和度。本研究的目的是评估唾液缓冲能力的定量评估与Ip(HA)之间与致龋潜力相关的关系。
收集33名患者的刺激性全唾液，使用手持pH计测量样本的初始pH值。然后用0.1N HCl滴定样本以评估缓冲能力，并将其分为三组（高、中、低）。在测量样本中钙和磷酸盐离子的浓度后，使用离子浓度和pH值计算Ip(HA)。使用Kruskal Wallis和Mann-Whitney非参数检验分析三组之间平均pH值、钙、磷酸盐离子浓度和log[Ip(HA)]的差异，p<0.05。
在滴定50微升HCl后，各缓冲能力组之间的平均pH值和Ip(HA)存在统计学差异。此外，在滴定50微升HCl后，缓冲能力与log[Ip(HA)]之间存在极好的相关性。
HCl滴定后唾液的pH值变化对Ip(HA)的速率有显著影响。
