Yassaei Soghra, Nasr Ali, Zandi Hengameh, Motallaei Mohammad Nima
Department of Orthodontics, Faculty of Dentistry, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
Department of Microbiology, School of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
Dental Press J Orthod. 2020 Mar;25(2):52-60. doi: 10.1590/2177-6709.25.2.052-060.oar. Epub 2020 May 29.
Plaque accumulation can cause white spot lesions. Adding nanoparticles to composites can be effective in reducing the number and function of microorganisms.
The aim of this study was to evaluate the antibacterial effects of orthodontic composites containing different nanoparticles on Streptococcus mutans at different times.
Hydroxyapatite, titanium oxides, zinc oxide, copper oxide and silver oxide nanoparticles were prepared at 0.5% and 1% weight concentrations. Accordingly, ten study groups and one control group were obtained. Then, 26 composite discs were prepared from each group. Strain of Streptococcus mutans was cultured, and colonies of Streptococcus mutans were counted. Further bacterial culture was swapped onto enriched Mueller-Hinton agar. The composites were placed on the culture medium, and after incubation the diameter of growth inhibition was measured. To investigate the long-term effect of nanoparticles, the colonies were counted at days 3, 15 and 30.
The results showed that 1% copper oxide and 1% silver oxide significantly reduced the number of bacteria (p< 0.05), but there was no significant difference between the other groups and control group (p> 0.05). At day three, there was a significant difference between control group and 0.5% silver oxide, 1% silver oxide and 1% copper oxide groups (p< 0.05). However, colonies had grown in all groups at day 30 but showed no significant difference with control group (p> 0.05).
Addition of 1% copper oxide and 1% silver oxide has short-term antibacterial effects, so the clinical use of these nanoparticles cannot be justified.
菌斑堆积会导致白斑病变。在复合材料中添加纳米颗粒可有效减少微生物的数量和功能。
本研究旨在评估含不同纳米颗粒的正畸复合材料在不同时间对变形链球菌的抗菌效果。
制备重量浓度为0.5%和1%的羟基磷灰石、二氧化钛、氧化锌、氧化铜和氧化银纳米颗粒。据此，获得了十个研究组和一个对照组。然后，每组制备26个复合圆盘。培养变形链球菌菌株并计数变形链球菌菌落。将进一步的细菌培养物接种到富集的穆勒-欣顿琼脂上。将复合材料置于培养基上，孵育后测量生长抑制直径。为了研究纳米颗粒的长期效果，在第3天、第15天和第30天对菌落进行计数。
结果表明，1%的氧化铜和1%的氧化银显著减少了细菌数量（p<0.05），但其他组与对照组之间无显著差异（p>0.05）。在第3天，对照组与0.5%氧化银、1%氧化银和1%氧化铜组之间存在显著差异（p<0.05）。然而，在第30天所有组中菌落均已生长，但与对照组无显著差异（p>0.05）。
添加1%的氧化铜和1%的氧化银具有短期抗菌效果，因此这些纳米颗粒的临床应用尚无依据。
