Zhou Wen, Peng Xinyu, Zhou Xuedong, Bonavente Andrea, Weir Michael D, Melo Mary Anne S, Imazato Satoshi, Oates Thomas W, Cheng Lei, Xu Hockin H K
State Key Laboratory of Oral Diseases, Department of Operative Dentistry and Endodontics, West China School of Stomatology, National Clinical Research Centre for Oral Diseases, Sichuan University, Chengdu 610041, China.
Department of Advanced Oral Sciences and Therapeutics, University of Maryland Dental School, Baltimore, MD 21201, USA.
Int J Mol Sci. 2020 Sep 2;21(17):6369. doi: 10.3390/ijms21176369.
Secondary caries often occurs at the tooth-composite margins. This study developed a novel bioactive composite containing DMAHDM (dimethylaminohexadecyl methacrylate) and NACP (nanoparticles of amorphous calcium phosphate), inhibiting caries at the enamel restoration margins in an in vitro saliva-derived biofilm secondary caries model for the first time. Four composites were tested: (1) Heliomolar nanocomposite, (2) 0% DMAHDM + 0% NACP, (3) 3% DMAHDM + 0% NACP, (D) 3% DMAHDM + 30% NACP. Saliva-derived biofilms were tested for antibacterial effects of the composites. Bovine enamel restorations were cultured with biofilms, Ca and P ion release of nanocomposite and enamel hardness at the enamel restoration margins was measured. Incorporation of DMAHDM and NACP into composite did not affect the mechanical properties ( > 0.05). The biofilms' CFU (colony-forming units) were reduced by 2 logs via DMAHDM ( < 0.05). Ca and P ion release of the nanocomposite was increased at cariogenic low pH. Enamel hardness at the margins for DMAHDM group was 25% higher than control ( < 0.05). With DMAHDM + NACP, the enamel hardness was the greatest and about 50% higher than control ( < 0.05). Therefore, the novel composite containing DMAHDM and NACP was strongly antibacterial and inhibited enamel demineralization, resulting in enamel hardness at the margins under biofilms that approached the hardness of healthy enamel.
继发龋常发生在牙齿与复合树脂的边缘处。本研究开发了一种新型生物活性复合树脂，其含有甲基丙烯酸二甲氨基十六酯（DMAHDM）和无定形磷酸钙纳米颗粒（NACP），首次在体外唾液来源生物膜继发龋模型中抑制牙釉质修复边缘处的龋齿。测试了四种复合树脂：（1）Heliomolar纳米复合树脂，（2）0% DMAHDM + 0% NACP，（3）3% DMAHDM + 0% NACP，（4）3% DMAHDM + 30% NACP。测试了唾液来源生物膜对复合树脂的抗菌效果。用生物膜培养牛牙釉质修复体，测量纳米复合树脂的钙和磷离子释放以及牙釉质修复边缘处的牙釉质硬度。将DMAHDM和NACP加入复合树脂中不影响其机械性能（P>0.05）。通过DMAHDM，生物膜的菌落形成单位（CFU）减少了2个对数级（P<0.05）。在致龋性低pH值下，纳米复合树脂的钙和磷离子释放增加。DMAHDM组边缘处的牙釉质硬度比对照组高25%（P<0.05）。对于DMAHDM + NACP，牙釉质硬度最大，比对照组高约50%（P<0.05）。因此，含有DMAHDM和NACP的新型复合树脂具有很强的抗菌性并抑制牙釉质脱矿，使得生物膜下边缘处的牙釉质硬度接近健康牙釉质的硬度。
