Dental Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran.
Department of Orthodontics, Shahed University, Tehran, Iran.
Photodiagnosis Photodyn Ther. 2021 Sep;35:102295. doi: 10.1016/j.pdpdt.2021.102295. Epub 2021 Apr 15.
Uncontrolled accumulation of microbial plaque and formation of biofilm on the surface orthodontic acrylic removable appliances increases the risk of enamel decalcification and periodontal diseases. The purpose of the present study was to evaluate antimicrobial activities, anti-virulence potencies, and mechanical properties of orthodontic acrylic resin containing different concentrations of Ulva lactuca (a green marine macroalga) following photo-activation against Streptococcus mutans.
Minimum inhibitory concentration (MIC) of U. lactuca was determined against S. mutans. Acrylic resin specimens with different concentrations of U. lactuca (0.2 %, 0.5 %, 1%, 2.5 %, 5%, and 10 % weight/weight) were fabricated. Flexural strength values, antimicrobial effects, and anti-biofilm activities of samples were assessed in comparison with original acrylic resin as the control group. Also, the expression of the virulence-associated genes was assessed by quantitative real-time polymerase chain reaction.
U. lactuca at concentrations of 1-10% significantly reduced the S. mutans growth rate by 20.3%-63.3% in comparison to the control group (P < 0.05). Therefore, the concentration of 1% of U. lactuca was considered as a MIC. The highest and lowest flexural strength values were observed in the control group (43.5 ± 2.4 MPa) and the group with a 10 % concentration of U. lactuca (19.2 ± 1.8 MPa), respectively. Flexural strength values decreased in samples containing 2.5 %, 5%, and 10 % concentrations of U. lactuca in comparison to the control group significantly (P > 0.05). In the disc agar diffusion test, the growth inhabitation zones around samples containing different concentrations of photo-activated U. lactuca ranged from 13 mm to 25 mm in diameter. Interestingly, the anti-biofilm activity of U. lactuca-mediated aPDT against S. mutans was dose-dependent. Additionally, the sub-MIC dose of U. lactuca (0.5 %) following photo-activation could significantly decrease the expression levels of gtfB, gtfC, and gtfD to 4.1-, 5.3-, and 7.4-fold, respectively.
Adding photo-activated U. lactuca to the orthodontic acrylic resin at a concentration of 1% increases its antibacterial and anti-biofilm activities besides not detrimentally affects its flexural strength.
微生物菌斑在正畸可摘义齿表面的不受控制的积累和生物膜的形成增加了釉质脱矿和牙周病的风险。本研究的目的是评价光激活后含不同浓度浒苔（一种绿色海洋大型藻类）的正畸丙烯酸树脂对变形链球菌的抗菌活性、抗毒力和机械性能。
测定浒苔对变形链球菌的最小抑菌浓度（MIC）。用不同浓度的浒苔（0.2%、0.5%、1%、2.5%、5%和 10%重量/重量）制备丙烯酸树脂标本。与原始丙烯酸树脂作为对照组相比，评估样品的弯曲强度值、抗菌效果和抗生物膜活性。此外，通过实时定量聚合酶链反应评估毒力相关基因的表达。
与对照组相比，浒苔浓度为 1%至 10%时，变形链球菌的生长速度显著降低 20.3%-63.3%（P<0.05）。因此，浒苔浓度为 1%被认为是 MIC。在对照组（43.5±2.4 MPa）和浒苔浓度为 10%的组（19.2±1.8 MPa）中观察到最高和最低的弯曲强度值。与对照组相比，含有 2.5%、5%和 10%浓度浒苔的样品的弯曲强度值显著降低（P>0.05）。在圆盘琼脂扩散试验中，不同浓度光激活浒苔周围的抑菌环直径为 13-25 毫米。有趣的是，浒苔介导的 aPDT 对变形链球菌的抗生物膜活性呈剂量依赖性。此外，光激活后浒苔的亚 MIC 剂量（0.5%）可使 gtfB、gtfC 和 gtfD 的表达水平分别显著降低 4.1、5.3 和 7.4 倍。
在正畸丙烯酸树脂中添加浓度为 1%的光激活浒苔可提高其抗菌和抗生物膜活性，而不会对其弯曲强度产生不利影响。
