Objectives

Dental plaque build-up on the cervical area adjacent to gingival margins is a trigger factor for secondary caries around restored root caries lesions. Dimethylaminohexadecyl methacrylate (DMAHDM) and amorphous calcium phosphate nanoparticles (NACP) impart anti-caries effect by reducing the bacterial growth and releasing high concentrations of calcium and phosphate ions, respectively. The present study explored the optimization and formulation of dental composite with increased concentration of DMAHDM combined with NACP and its effect on mechanical behavior and antibacterial response.

Methods

DMAHDM was incorporated into dental composite formulation at 3% and 5% with 20% NACP fillers. Mechanical properties were assessed by flexural strength and elastic modulus. The cationic charge density of the samples was determined using fluorescein staining assay. A human saliva-derived microcosm biofilm model was used to assess antibacterial response via colony-forming units, metabolic activities, lactic acid production, and live/dead assay. Surface roughness was measured after 48 h-biofilm formation.

Results

The viability of human saliva microcosm biofilms was DMAHDM concentration-dependent, where all the microbiological assays were substantially reduced in the presence of 5%DMAHDM. The increased DMAHDM concentration mirrors an increased surface charge density of composites by 8–12 folds and reduced the growth of cariogenic species by 2–5 log (p ≤ 0.05). Metabolic activity and lactic acid were reduced by 70–90% and 48–99%, respectively. Increasing DMAHDM concentration up to 5% and its association with NACP fillers did not adversely affect the mechanical properties.

Significance

A highly potent antibiofilm bioactive composite for root caries restorations having DMAHDM-NACP could be flexibly tailored during formulation without detrimental outcome for mechanical function. The enhanced antibacterial performance of the novel bioactive composite has great potential to suppress the dental plaque build-up that triggers secondary caries around the restored root caries lesions.

中文翻译：

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季铵盐单体对根腐病修复用高性能生物活性复合材料设计的浓度依赖性。

目标

邻近牙龈边缘的宫颈区域上的牙菌斑堆积是恢复的根龋病变周围继发龋的触发因素。甲基丙烯酸二甲基氨基十六烷基酯（DMAHDM）和无定形磷酸钙纳米颗粒（NACP）通过减少细菌生长并释放高浓度的钙离子和磷酸根离子来赋予抗龋效果。本研究探讨了DMAHDM与NACP结合使用浓度增加的牙科复合材料的优化和配方及其对机械性能和抗菌反应的影响。

方法

将DMAHDM与20％NACP填料以3％和5％的比例掺入牙科复合材料配方中。通过弯曲强度和弹性模量评估机械性能。使用荧光素染色测定法确定样品的阳离子电荷密度。人类唾液来源的微观生物膜模型用于通过菌落形成单位，代谢活性，乳酸产生和活/死分析评估抗菌反应。在48小时生物膜形成后测量表面粗糙度。

结果

人唾液微观世界生物膜的生存能力是DMAHDM浓度依赖性的，其中所有微生物分析在5％DMAHDM的存在下均显着降低。增加DMAHDM浓度镜复合材料的8-12倍的增加的表面电荷密度和由2-5日志（减少龋齿物种的生长p  ≤0.05）。代谢活性和乳酸分别降低了70–90％和48–99％。将DMAHDM浓度提高到5％，并且其与NACP填料的结合不会对机械性能产生不利影响。

意义

具有DMAHDM-NACP的用于龋齿修复的高效抗生物膜生物活性复合材料可在配制过程中灵活定制，而不会损害机械功能。新型生物活性复合材料具有增强的抗菌性能，具有极大的潜力来抑制牙菌斑的积聚，而牙菌斑的积聚会触发恢复的根龋病灶周围的继发性龋齿。