Reyhani Mohammad Frough, Ghasemi Negin, Milani Amin Salem, Abbasi Asl Masoumeh
Dept. of Endodontics, Dental Faculty, Tabriz University of Medical Sciences, Tabriz, Iran.
Dept. of Endodontics, Dental and Periodontal Research Center, Dental Faculty, Tabriz University of Medical Sciences, Tabriz, Iran.
J Dent (Shiraz). 2023 Jun;24(2):194-199. doi: 10.30476/dentjods.2022.94792.1812.
() is one of the most important microorganisms in the evaluation of the antibacterial effects of intra-canal medications due to its ability to penetrate dentinal tubules and form biofilms. Calcium hydroxide, as the most common intra-canal medication, has little effect on this bacterial species. In contrast, it is hypothesized that nano scale hydroxide particles are more effective due to their smaller size and higher surface-to-volume ratio.
This study aimed to investigate the antimicrobial effect of nano-calcium hydroxide on the four- and six-week-old intra-canal biofilms.
In this study, seventy maxillary single-canal premolar teeth were used. After cleaning and preparing the root canals, the samples were placed in vials containing solution in which the culture medium was changed daily. Each group was divided into three subgroups (n=20) in terms of the antimicrobial material used as the intra-canal medication including subgroup 1: nano-calcium hydroxide, subgroup 2: calcium hydroxide, and subgroup 3: phosphate-buffered saline solution (control group). The antimicrobial property was measured by counting colony-forming units (CFU). The data were analyzed with Mann-Whitney U and Kruskal-Wallis tests. Statistical significance was set at < 0.05.
The mean CFU in the six-week-old biofilm group was significantly higher than that in the four-week-old biofilm (= 0.003). A comparison between the subgroups showed a significant decrease in CFU in the six-week-old biofilm in the nano-calcium hydroxide subgroup compared to that in the calcium hydroxide subgroup (= 0.002). However, the decrease was not significant in the four-week-old biofilm group (= 0.06).
Under the limitations of the present study, the antimicrobial properties of nano-calcium hydroxide were higher than conventional calcium hydroxide on mature biofilm, whereas the antimicrobial properties were not clinically and significantly different on immature biofilm.
（）是评估根管内药物抗菌效果时最重要的微生物之一，因为它能够穿透牙本质小管并形成生物膜。氢氧化钙作为最常用的根管内药物，对这种细菌几乎没有作用。相比之下，据推测纳米级氢氧化钙颗粒因其尺寸更小和更高的表面积与体积比而更有效。
本研究旨在调查纳米氢氧化钙对4周龄和6周龄根管内生物膜的抗菌作用。
在本研究中，使用了70颗上颌单根管前磨牙。根管清洁和预备后，将样本置于含有溶液的小瓶中，每天更换培养基。根据用作根管内药物的抗菌材料，每组分为三个亚组（n = 20），包括亚组1：纳米氢氧化钙，亚组2：氢氧化钙，亚组3：磷酸盐缓冲盐溶液（对照组）。通过计算菌落形成单位（CFU）来测量抗菌性能。数据采用Mann-Whitney U检验和Kruskal-Wallis检验进行分析。统计学显著性设定为<0.05。
6周龄生物膜组的平均CFU显著高于4周龄生物膜组（= 0.003）。亚组之间的比较显示，与氢氧化钙亚组相比，纳米氢氧化钙亚组中6周龄生物膜的CFU显著降低（= 0.002）。然而，在4周龄生物膜组中，这种降低并不显著（= 0.06）。
在本研究的局限性下，纳米氢氧化钙对成熟生物膜的抗菌性能高于传统氢氧化钙，而对未成熟生物膜的抗菌性能在临床上没有显著差异。
