Division of Preventive Dentistry, University of Zürich Center of Dental Medicine, Switzerland.
J Endod. 2011 May;37(5):693-6. doi: 10.1016/j.joen.2011.02.019. Epub 2011 Mar 23.
When sodium hypochlorite solutions react with tissue, their pH drops and tissue sorption decreases. We studied whether stabilizing a NaOCl solution at a high pH would increase its soft-tissue dissolution capacity and effects on the dentin matrix compared with a standard NaOCl solution of the same concentration and similar initial pH.
NaOCl solutions were prepared by mixing (1:1) a 10% stock solution with water (standard) or 2 mol/L NaOH (stabilized). Physiological saline and 1 mol/L NaOH served as the controls. Chlorine content and alkaline capacity of NaOCl solutions were determined. Standardized porcine palatal soft-tissue specimens and human root dentin bars were exposed to test and control solutions. Weight loss percentage was assessed in the soft-tissue dissolution assay. Three-point bending tests were performed on the root dentin bars to determine the modulus of elasticity and flexural strength. Values between groups were compared using one-way analysis of variance with the Bonferroni correction for multiple testing (α < .05).
Both solutions contained 5% NaOCl. One milliliter of the standard and the stabilized solution consumed 4.0 mL and 13.7 mL of a 0.1-mol/L HCl solution before they reached a pH level of 7.5, respectively. The stabilized NaOCl dissolved significantly more soft tissue than the standard solution, and the pH remained high. It also caused a higher loss in elastic modulus and flexure strength (P < .05) than the control solutions, whereas the standard solution did not.
NaOH-stabilized NaOCl solutions have a higher alkaline capacity and are thus more proteolytic than standard counterparts.
当次氯酸钠溶液与组织反应时，其 pH 值会下降，组织吸附能力会降低。我们研究了将高 pH 值的次氯酸钠溶液稳定化是否会增加其对软组织的溶解能力，并与相同浓度和相似初始 pH 值的标准次氯酸钠溶液相比，对牙本质基质的影响。
将 10%的储备溶液与水（标准）或 2 mol/L NaOH（稳定）以 1:1 的比例混合制备次氯酸钠溶液。生理盐水和 1 mol/L NaOH 用作对照。测定次氯酸钠溶液的氯含量和碱性能力。将标准化的猪腭软组织标本和人牙根牙本质条暴露于测试和对照溶液中。在软组织溶解测定中评估重量损失百分比。对牙根牙本质条进行三点弯曲试验，以确定弹性模量和弯曲强度。使用单向方差分析比较组间值，并使用 Bonferroni 校正进行多重检验（α<0.05）。
两种溶液均含有 5%的次氯酸钠。标准溶液和稳定化溶液分别需要 1 毫升 0.1mol/L HCl 溶液才能达到 pH 值 7.5，消耗的盐酸溶液体积分别为 4.0 毫升和 13.7 毫升。稳定化次氯酸钠溶解的软组织明显多于标准溶液，且 pH 值保持较高水平。它还导致弹性模量和弯曲强度的损失高于对照溶液（P<0.05），而标准溶液则没有。
NaOH 稳定化次氯酸钠溶液具有更高的碱性能力，因此比标准对应物更具蛋白水解能力。
