Abstract:

Objective To investigate the antibacterial activity to Streptococcus mutans of a nisin-containing single-bond universal adhesive. Methods Nisin was mixed into the bonding agent to produce concentrations ranging from 0.01 g/mL to 0.05 g/mL for the experiments, and adhesive without nisin was used as the control. Dentin-resin specimens were prepared for the microtensile strength test to evaluate changes in the bonding strength. The proper concentrations were selected for more tests. ① An agar diffusion test was applied with filter paper to detect the release of nisin, and adhesive without nisin was used as the negative control, 0.01 g/mL Nisin aqueous solution was used as the positive control. ② Solidification; resin adhesive specimens were prepared for the assessment of direct contact inhibition activity. ③ Confocal laser scanning microscopy was used to examine the effect of the adhesive on the biological film activity and the ability of Streptococcus mutans to produce extracellular polysaccharides. Results Nisin did not significantly reduce the bond strength of the modified adhesive at 0.01-0.03 g/mL (P < 0.05); these concentrations were selected for the subsequent antibiosis experiment. Rings could not be observed in the agar diffusion test, except for in the group of adhesive modified with 0.01-0.03 g/mL nisin. Resin adhesive with 0.01-0.03 g/mL nisin could significantly inhibit the proliferation of Streptococcus mutans on the surface of the specimens. The confocal laser scanning microscopy results indicate that only the adhesive resin modified with nisin could reduce the bacteria in the biofilm and the production of extracellular polysaccharides. Conclusion Single-bond universal adhesive with 0.01-0.03 g/mL nisin can inhibit the growth of Streptococcus mutans and its biofilms on the bonding interface, as well as decrease the production of extracellular polysaccharides, and thus has the potential to decrease the occurrence of secondary caries.

Key words: Nisin, Streptococcus mutans, Biofilm, Extracellular polysaccharides, Resin adhesive

摘要：

目的 检测不同浓度乳酸链球菌素（Nisin）改性通用型树脂粘接剂（简称粘接剂）对变异链球菌的抑菌作用。方法 室温避光条件下,将Nisin加入粘接剂中,震荡混匀,配置Nisin浓度为0.01 g/mL（0.01 g/mL组）、0.02 g/mL（0.02 g/mL组）、0.03 g/mL（0.03 g/mL组）、0.04 g/mL（0.04 g/mL组）、0.05 g/mL（0.05 g/mL组）的粘接剂溶液,以不添加Nisin的粘接剂作为对照组,进行微拉伸实验,评估Nisin对粘接剂粘接强度的影响。筛选出与对照组粘接强度无差异的改性粘接剂为实验组,进一步进行：①琼脂扩散实验,检测固化粘接剂中Nisin的释出,其中以不添加Nisin的粘接剂为阴性对照组,以0.01 g/mL Nisin水溶液为阳性对照组;②直接接触抑菌实验,检测粘接剂对变异链球菌的直接接触抑菌能力;③生物膜活性分析,以激光共聚焦扫描显微镜观察各组变异链球菌生物膜菌量、厚度及胞外多糖产量情况,通过以上指标评价改性粘接剂对变异链球菌生物膜结构、活性和产胞外多糖能力的影响。结果 微拉伸实验筛选出0.01 g/mL组、0.02 g/mL组和0.03 g/mL组进行之后的琼脂扩散实验、直接接触抑菌实验、生物膜活性分析。琼脂扩散实验0.01 g/mL组、0.02 g/mL组、0.03 g/mL组未见明显抑菌环;直接接触抑菌实验0.01 g/mL组、0.02 g/mL组、0.03 g/mL组Nisin改性粘接剂可明显抑制样本表面变异链球菌增殖;共聚焦显微镜扫描结果显示,0.01 g/mL组、0.02 g/mL组、0.03 g/mL组变异链球菌生物膜中细菌数量减少、厚度降低、胞外多糖活菌比例降低。结论 Nisin 浓度为0.01 g/mL、0.02 g/mL、0.03 g/mL的改性通用型粘接剂能抑制变异链球菌粘附及生长,具备减少树脂牙本质粘接界面继发龋发生的潜能。

关键词: 乳酸链球菌素, 变异链球菌, 生物膜, 胞外多糖, 树脂粘接剂