Silva Igor A, de Souza Araújo Isaac J, Stipp Rafael N, Puppin Rontani Regina M
Private practice, Piracicaba, Brazil.
Dental Materials Graduate Program, Department of Operative Dentistry, Piracicaba Dental School, State University of Campinas, Piracicaba, SP, Brazil.
Am J Dent. 2020 Oct;33(5):273-276.
To evaluate the effect of glass-ionomer cement (GIC) on gene expression (gtfC, gtfD, covR, and vicR) of Streptococcus mutans (S. mutans) biofilms at 2, 4 and 24 hours.
Six groups were tested according to the materials and time observation, as follows: ceramic (IPS Empress Esthetic), as the control group, and GIC (Ketac Molar Easymix); and time points of S. mutans biofilm formation (2, 4, and 24 hours). Round-shaped samples (10 x 2 mm) of each material were prepared according to the manufacturers' specifications. GIC discs were handled in a laminar flow hood under aseptic conditions and stored at 100% relative humidity at 37°C for 24 hours to complete setting reaction. The samples were placed in a 24-well plate and immersed in 1.5 ml BHI + 1% sucrose with an inoculum of S. mutans UA159 to allow biofilm growth during 2, 4, and 24 hours. Next, the samples were removed, vortexed and centrifuged to collect cell pellets (n=5) for each material and time point. Pellets were stored at -80°C. Then, RNA was purified using the RNeasy Mini Kit protocol. The RNA was converted in cDNA using iScript cDNA Synthesis according to the manufacturer's recommendations. Analysis of gtfC, gtfD, vicR, and covR expressions was performed using Step One Real-Time qPCR device with specific primers for each gene and the analysis normalized by 16S reference gene expression. Data from gtfC, gtfD, and vicR were analyzed by t-test to compare between groups while Mann-Whitney was used to analyze covR expression (α= 0.05).
No significant differences at 2 and 4 hours between materials for all analyzed genes were noted. However, in the 24-hour period, a significant decrease in gtfC and vicR expressions were observed, while covR expression increased when GIC was compared to ceramic.
The use of glass-ionomer cement decreased the virulence of S. mutans biofilms, which may imply a reduced bacterial cariogenic potential.
评估玻璃离子水门汀（GIC）在2小时、4小时和24小时对变形链球菌（S. mutans）生物膜基因表达（gtfC、gtfD、covR和vicR）的影响。
根据材料和时间观察分为六组，如下：陶瓷（IPS Empress Esthetic）作为对照组，以及GIC（Ketac Molar Easymix）；以及变形链球菌生物膜形成的时间点（2小时、4小时和24小时）。每种材料的圆形样本（10×2毫米）根据制造商的规格制备。GIC圆盘在无菌条件下的层流罩中处理，并在37°C、100%相对湿度下储存24小时以完成凝固反应。将样本置于24孔板中，浸入含有变形链球菌UA159接种物的1.5毫升脑心浸液培养基（BHI）+1%蔗糖中，以允许生物膜在2小时、4小时和24小时内生长。接下来，取出样本，涡旋并离心，以收集每种材料和时间点的细胞沉淀（n = 5）。沉淀储存在-80°C。然后，使用RNeasy Mini试剂盒方案纯化RNA。根据制造商的建议，使用iScript cDNA合成将RNA转化为cDNA。使用Step One实时定量聚合酶链反应（qPCR）设备，针对每个基因使用特异性引物进行gtfC、gtfD、vicR和covR表达分析，并通过16S参考基因表达进行标准化分析。gtfC、gtfD和vicR的数据通过t检验进行组间比较，而Mann-Whitney检验用于分析covR表达（α = 0.05）。
在2小时和4小时时，所有分析基因的材料之间未观察到显著差异。然而，在24小时期间，与陶瓷相比，当使用GIC时，观察到gtfC和vicR表达显著降低，而covR表达增加。
使用玻璃离子水门汀可降低变形链球菌生物膜的毒力，这可能意味着细菌致龋潜力降低。
