A new type of photocurable resin composite containing nano-MgO was synthesized in order to reduce the occurrence of secondary caries. Different mass ratios (0 %, 1 %, 2 %, 4 %, 8 %) of nano-MgO were added into resin composites. The antibacterial properties of nano-MgO powder and modified resin composites against Streptococcus mutans (S. mutans) were detected by antibacterial ring test and film contact test, respectively. Compressive strength (CS) and wear resistance were determined by a universal testing machine and an abrasion test machine. The results indicated that antibacterial activity and wear resistance of resin composites containing nano-MgO were superior to the control group (p < 0.05). The antibacterial rate reached as high as 99.4 % when the mass ratio of nano-MgO was 8 %. However, the CS values tended to decline as the content of nano-MgO increase. Hence, the addition of nano-MgO showed excellent antibacterial property to resin composites and enhanced wear resistance, but was detrimental to their mechanical properties.

中文翻译：

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一种新型的纳米MgO抗菌光固化树脂复合材料的研究。

为了减少次生龋齿的发生，合成了一种新型的含有纳米MgO的光固化树脂复合材料。将不同质量比（0％，1％，2％，4％，8％）的纳米MgO添加到树脂复合材料中。分别通过抗菌环试验和膜接触试验检测了纳米MgO粉体和改性树脂复合材料对变形链球菌的抗菌性能。抗压强度（CS）和耐磨性由通用测试机和磨损测试机确定。结果表明，含纳米MgO的树脂复合材料的抗菌活性和耐磨性均优于对照组（p <0.05）。当纳米MgO的质量比为8％时，抗菌率高达99.4％。然而，随着纳米MgO含量的增加，CS值趋于下降。因此，纳米MgO的添加对树脂复合材料显示出优异的抗菌性能并增强了耐磨性，但不利于其机械性能。