Health and Technology Rural Center, Federal University of Campina Grande, Patos, PB, Brazil.
J Appl Oral Sci. 2012 Sep-Oct;20(5):568-75. doi: 10.1590/s1678-77572012000500013.
Since bacteria remain in the dentin following caries removal, restorative materials with antibacterial properties are desirable to help maintaining the residual microorganisms inactive. The adhesive system Clearfil Protect Bond (PB) contains the antibacterial monomer 12-methacryloyloxydodecylpyridinium bromide (MDPB) in its primer, which has shown antimicrobial activity. However, its bactericidal effect against biofilm on the dentin has been little investigated.
The aim of this study was to analyze by confocal laser scanning microscopy (CLSM) and viable bacteria counting (CFU) the MDPB bactericidal effect against S. mutans biofilm on the dentin surface.
Bovine dentin surfaces were obtained and subjected to S. mutans biofilm formation in BHI broth supplemented with 1% (w/v) sucrose for 18 h. Samples were divided into three groups, according to the primer application (n=3): Clearfil Protect Bond (PB), Clearfil SE Bond, which does not contain MDPB, (SE) and saline (control group). After the biofilm formation, Live/ Dead stain was applied directly to the surface of each sample. Next, 10 µL of each primer were applied on the samples during 590 s for the real-time CLSM analysis. The experiment was conducted in triplicate. The primers and saline were also applied on the other dentin samples during 20, 90, 300 and 590 s (n=9 for each group and period evaluated) and the CFU were assessed by colonies counting.
The results of the CLSM showed that with the Se application, although non-viable bacteria were detected at 20 s, there was no increase in their count during 590 s. In contrast, after the PB application there was a gradual increase of non-viable bacteria over 590 s.
The quantitative analysis demonstrated a significant decrease of S. mutans CFU at 90 s PB exposure and only after 300 s of Se application. Protect Bond showed an earlier antibacterial effect than Se Bond.
本研究旨在通过共聚焦激光扫描显微镜（CLSM）和活菌计数（CFU）分析 12-甲丙烯氧十二烷基溴化吡啶鎓（MDPB）对牙本质表面变形链球菌生物膜的杀菌作用。
从牛牙本质表面获得样本，并在 BHI 肉汤中添加 1%（w/v）蔗糖培养 18 小时，形成变形链球菌生物膜。根据应用的底漆（n=3）将样本分为三组：含 MDPB 的 Clearfil Protect Bond（PB）、不含 MDPB 的 Clearfil SE Bond（SE）和生理盐水（对照组）。生物膜形成后，直接将 Live/Dead 染色剂应用于每个样本表面。接下来，将 10 µL 的每种底漆应用于样本上 590 秒，进行实时 CLSM 分析。该实验重复进行了三次。在 20、90、300 和 590 秒（每组和每个时间段评估的 n=9）期间，还将底漆和生理盐水应用于其他牙本质样本，并通过菌落计数评估 CFU。
CLSM 结果显示，尽管在 20 秒时已经检测到非存活细菌，但在 590 秒内其数量没有增加。相比之下，在 PB 应用后，非存活细菌在 590 秒内逐渐增加。
定量分析表明，在 PB 暴露 90 秒后，变形链球菌 CFU 显著减少，而仅在 SE 应用 300 秒后才减少。与 SE 键相比，Protect Bond 显示出更早的抗菌作用。
