Saberi Eshagh Ali, Farhad-Mollashahi Narges, Saberi Mersad
Oral and dental Diseases Research Center, Department of Endodontics, Faculty of Dentistry, Zahedan University of Medical Sciences, Zahedan, Iran.
General Dentist, Zahedan, Iran.
Iran Endod J. 2019 Spring;14(2):139-143. doi: 10.22037/iej.v14i2.23120.
Sodium hypochlorite (NaOCl) is extensively used in root canal treatment and its efficacy depends on the concentration of free available chlorine (FAC). This study aimed to assess the chlorine content of 10 domestically manufactured household bleach products available in the Iranian market and evaluate the effect of temperature, time and daily bottle uncapping on FAC concentration and pH of these products.
One-liter bottles of 10 available brands of household bleach (=4 of each brand) were collected and randomly divided into four groups (=10). Two groups were refrigerated at 4C while the remaining two were stored at room temperature. One group of refrigerated and one group of room temperature samples were subjected to daily bottle uncapping followed by agitation and recapping for 3 months (six times a week to simulate weekly office work). The remaining bottles remained untouched and served as controls. The concentration of FAC in each sample was measured using the iodometric titration assay, and the pH was measured using a calibrated pH-meter at baseline and 1, 2 and 3 months. The results were analyzed using the one-way ANOVA and -test.
The mean concentration of FAC in the solutions was 4.87±0.19% at baseline. The measured concentration of sodium hypochlorite was different from the labeled value. The concentration of FAC decreased over time in all samples; the greatest reduction occurred in room temperature samples subjected to daily uncapping while the smallest reduction occurred in refrigerated, capped bottles (19% and 1.9%, respectively). The pH of all products decreased over time. The mean reduction in pH was 1.1 for the samples stored at room temperature for 3 months and 0.8 for the refrigerated samples.
This study showed that the expected concentration of sodium hypochlorite solution made of household bleach for endodontic purposes is different from its actual concentration.
次氯酸钠（NaOCl）广泛用于根管治疗，其疗效取决于游离有效氯（FAC）的浓度。本研究旨在评估伊朗市场上10种国产家用漂白剂产品的氯含量，并评估温度、时间和每日开盖对这些产品的FAC浓度和pH值的影响。
收集10个可用品牌的一升装家用漂白剂瓶（每个品牌4瓶），随机分为四组（每组10瓶）。两组在4℃冷藏，其余两组在室温下储存。一组冷藏样品和一组室温样品每天开盖，然后振荡并重新封盖3个月（每周六次以模拟每周的办公室工作）。其余瓶子保持原状作为对照。使用碘量滴定法测定每个样品中FAC的浓度，并使用校准的pH计在基线以及1、2和3个月时测量pH值。结果采用单因素方差分析和t检验进行分析。
基线时溶液中FAC的平均浓度为4.87±0.19%。测得的次氯酸钠浓度与标签值不同。所有样品中FAC的浓度均随时间下降；下降幅度最大的是每天开盖的室温样品，而下降幅度最小的是冷藏、封盖的瓶子（分别为19%和1.9%）。所有产品的pH值均随时间下降。在室温下储存3个月的样品pH值平均下降1.1，冷藏样品pH值平均下降0.8。
本研究表明，用于牙髓治疗的家用漂白剂制成的次氯酸钠溶液的预期浓度与其实际浓度不同。
