Resin composites are the material of choice for dental restorative treatment in oral health care. However, the inherent composition of this class of material commonly results in microbial adherence and colonization, which carries the potential risk of recurrent carious lesions around dental restorations. The high risk of resin composites failure complicates the treatment of root caries, defined as the onset of tooth decay over the prone root surface of a tooth. The restorative treatment of root caries among high caries risk individuals, especially for senior patients, is a challenging, painful, and costly. The dysbiotic microbiota colonizes the composite’s surfaces and forms polymicrobial biofilms that are difficult to be dislodged by regular tooth brushing. This study assesses the antibiofilm performance of a surface contact killing antibacterial dental resin composites on the growth of microcosm biofilms using dental plaque sampled from patients with active root carious lesions as an inoculum. The designed formulations contain dimethylaminohexadecyl methacrylate (DMAHDM), a tailored quaternary ammonium monomer with an alkyl chain length of 16, at 3–5 wt.% in a base resin with and without 20 wt.% nanoparticles of amorphous calcium phosphate (NACP). Biofilms were grown on the tested resin composites using a 48 h plaque-derived microcosm biofilm model. Dental plaque collected from active root carious lesions was used as an inoculum to emulate the microbiota present in those lesions. The biofilm growth was assessed via the colony-forming unit (CFU) counts in four culture media, metabolic behavior, lactic acid production, and confocal microscopy. The percentage of reacted double bonds of the formulations was also investigated. The dental resin composites formulated with 3–5 wt.% DMAHDM and 20 wt.% NACP were effective at eradicating surface-attached biofilms from the total microbial load and each relevant cariogenic group: total streptococci, mutans streptococci, and lactobacilli. The metabolic activities and lactic acid production of the plaque-derived microcosm biofilms were reduced by 80–95%, respectively. Fewer viable microorganisms were observed over resin composites containing DMAHDM and NACP. Besides, all the experimental formulations demonstrated an acceptable degree of conversion values. This new strategy fits with ongoing dental caries preventive and minimally invasive approaches by preventing biofilm growth over-restored carious root lesions and improving the lifespan of dental restorations.

树脂复合材料是口腔保健中牙齿修复治疗的首选材料。但是，这类材料的固有成分通常会导致微生物的附着和定植，从而带来了牙齿修复体周围反复出现龋齿的潜在风险。树脂复合材料失效的高风险使龋齿的治疗复杂化，这被定义为在牙齿俯卧的根表面上开始蛀牙。在高龋风险人群中，特别是对老年患者，根龋的修复治疗是一项挑战，痛苦且昂贵的事情。有害生物菌群会在复合物的表面定居，并形成难以通过常规刷牙清除的微生物生物膜。这项研究使用从活动性根龋患者的牙菌斑中接种的牙菌斑评估了一种表面接触杀灭抗菌性牙科树脂复合物在微观生物膜生长上的抗生物膜性能。设计的配方中，甲基丙烯酸二甲基氨基十六烷基酯（DMAHDM）是一种量身定制的季铵单体，其烷基链长为16，在基础树脂中的含量为3-5 wt％，有无20％（重量）的无定形磷酸钙（NACP）纳米颗粒。使用48小时噬斑衍生的微观生物膜模型在测试的树脂复合材料上生长生物膜。从活跃的根龋病灶收集的牙菌斑用作接种物，以模拟这些病灶中存在的微生物群。通过四种培养基中的菌落形成单位（CFU）计数，代谢行为，乳酸的产生，以及共聚焦显微镜。还研究了制剂中反应的双键的百分比。用3-5％（重量）的DMAHDM和20％（重量）的NACP配制的牙科树脂复合材料可以有效地从总微生物负荷和每个相关的致癌基团中消除表面附着的生物膜：链球菌， 变形链球菌， 和 乳杆菌。菌斑来源的微观生物膜的代谢活性和乳酸产生分别降低了80–95％。在含有DMAHDM和NACP的树脂复合材料上观察到较少的存活微生物。此外，所有实验配方均显示出可接受的转化率值。这项新策略通过防止生物膜生长过度恢复龋齿根病变并改善牙齿修复的寿命，从而与正在进行的龋齿预防和微创方法相吻合。