Bidar Maryam, Eslami Neda, Naghavi Neda, Fasihi Zohreh, Attaran Mashhadi Negin
Professor of Endodontics, Dental Research Center, Faculty of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran.
Assistant Professor of Orthodontics, Dental Research Center, Faculty of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran.
J Dent Res Dent Clin Dent Prospects. 2015 Winter;9(1):1-5. doi: 10.15171/joddd.2015.001. Epub 2015 Mar 4.
Background and aims. Substituting chlorhexidine (CHX) for water has been shown to enhance antimicrobial activity of mineral trioxide aggregate (MTA). The purpose of this study was to compare the compressive strength of MTA mixed with distilled water, 0.12% and 0.2% chlorhexidine. Materials and methods. MTA was mixed according to manufacturer's instructions in group I (n = 20). In groups II & III, 0.12% and 0.2% CHX liquid was substituted for water, respectively. Samples were condensed with moderate force into 20 tubes with 1.5×5 mm dimensions and were allowed to set for 72 hours at 37°C in 100% humidity. After being removed from the molds, their compressive strength was determined using Instron testing machine. Each group was divided into two subgroups according to the time of testing (at 72 hours, and one week). Fractured surfaces of 4 specimens in each group were then evaluated under Scanning Electron Microscope (SEM) to determine their microstructure. One-way ANOVA, Tukey, and paired sample t-test was used for statistical analysis. P < 0.05 was set as significant. Results. There was no significant difference between three groups in terms of their compressive strength after 72 hours. However, the compressive strength of group II was significantly higher than group I (P = 0.034) and group III (P = 0.021) after one week. Crystalline microstructure was similar in all groups. Conclusion. Substitution of 0.012% chlorhexidine for water significantly increased the compressive strength of MTA at 1 week without significant change in crystalline structure.
背景与目的。已证明用氯己定（CHX）替代水可增强三氧化矿物凝聚体（MTA）的抗菌活性。本研究的目的是比较与蒸馏水、0.12%和0.2%氯己定混合的MTA的抗压强度。材料与方法。按照制造商说明在第I组（n = 20）中混合MTA。在第II组和第III组中，分别用0.12%和0.2%的CHX液体替代水。将样品以适度的力压入20根尺寸为1.5×5毫米的试管中，并在37°C、100%湿度下放置72小时。从模具中取出后，使用英斯特朗试验机测定其抗压强度。根据测试时间（72小时和一周）将每组分为两个亚组。然后在扫描电子显微镜（SEM）下评估每组4个标本的断裂表面，以确定其微观结构。采用单因素方差分析、Tukey检验和配对样本t检验进行统计分析。设定P < 0.05为有显著性差异。结果。72小时后，三组的抗压强度无显著差异。然而，一周后，第II组的抗压强度显著高于第I组（P = 0.034）和第III组（P = 0.021）。所有组的晶体微观结构相似。结论。用0.012%氯己定替代水可在1周时显著提高MTA的抗压强度，且晶体结构无显著变化。
