Toledano-Osorio Manuel, Osorio Raquel, Aguilera Fátima S, Medina-Castillo Antonio Luis, Toledano Manuel, Osorio Estrella, Acosta Sergio, Chen Ruoqiong, Aparicio Conrado
University of Granada, Faculty of Dentistry, Dental Materials Section, Colegio Máximo de Cartuja s/n, 18071, Granada, Spain.
University of Granada, NanoMyP. Spin-Off Enterprise, Edificio BIC-Granada. Av. Innovación 1, 18016, Armilla, Granada, Spain.
Acta Biomater. 2020 Jul 15;111:316-326. doi: 10.1016/j.actbio.2020.05.002. Epub 2020 May 19.
The objective was to assess doxycycline (Dox) and zinc (Zn) doped nanoparticles' (NPs) potential to protect the resin-dentin interface from cariogenic biofilm. Three groups of polymeric NPs were tested: unloaded, loaded with zinc and with doxycycline. NPs were applied after dentin etching. The disks were exposed to a cariogenic biofilm challenge in a Drip-Flow Reactor during 72 h and 7 d. Half of the specimens were not subjected to biofilm formation but stored 72 h and 7 d. LIVE/DEAD® viability assay, nano-dynamic mechanical assessment, Raman spectroscopy and field emission electron microscopy (FESEM) analysis were performed. The measured bacterial death rates, at 7 d were 46% for the control group, 51% for the undoped-NPs, 32% for Dox-NPs, and 87% for Zn-NPs; being total detected bacteria reduced five times in the Dox-NPs group. Zn-NPs treated samples reached, in general, the highest complex modulus values at the resin-dentin interface over time. Regarding the mineral content, Zn-NPs-treated dentin interfaces showed the highest mineralization degree associated to the phosphate peak and the relative mineral concentration. FESEM images after Zn-NPs application permitted to observe remineralization of the etched and non-resin infiltrated collagen layer, and bacteria were scarcely encountered. The combined antibacterial and remineralizing effects, when Zn-NPs were applied, reduced biofilm formation. Dox-NPs exerted an antibacterial role but did not remineralize the bonded interface. Undoped-NPs did not improve the properties of the interfaces. Application of Zn-doped NPs during the bonding procedure is encouraged. STATEMENT OF SIGNIFICANCE: Application of Zn-doped nanoparticles on acid etched dentin reduced biofilm formation and viability at the resin-dentin interface due to both remineralization and antibacterial properties. Doxycycline-doped nanoparticles also diminished oral biofilm viability, but did not remineralize the resin-dentin interface.
目的是评估多西环素（Dox）和锌（Zn）掺杂纳米颗粒（NPs）保护树脂 - 牙本质界面免受致龋生物膜侵害的潜力。测试了三组聚合物纳米颗粒：未负载、负载锌和负载多西环素的。纳米颗粒在牙本质酸蚀后应用。圆盘在滴流反应器中暴露于致龋生物膜挑战72小时和7天。一半的标本未进行生物膜形成，而是储存72小时和7天。进行了LIVE/DEAD®活力测定、纳米动态力学评估、拉曼光谱和场发射电子显微镜（FESEM）分析。在7天时，测量的细菌死亡率为：对照组46%，未掺杂纳米颗粒组51%，多西环素纳米颗粒组32%，锌纳米颗粒组87%；多西环素纳米颗粒组中总检测到的细菌减少了五倍。随着时间的推移，锌纳米颗粒处理的样品在树脂 - 牙本质界面通常达到最高的复数模量值。关于矿物质含量，锌纳米颗粒处理的牙本质界面显示出与磷酸盐峰和相对矿物质浓度相关的最高矿化程度。应用锌纳米颗粒后的FESEM图像允许观察蚀刻且未被树脂浸润的胶原层的再矿化，并且几乎未发现细菌。当应用锌纳米颗粒时，抗菌和再矿化的联合作用减少了生物膜形成。多西环素纳米颗粒发挥了抗菌作用，但未使粘结界面再矿化。未掺杂纳米颗粒未改善界面性能。鼓励在粘结过程中应用锌掺杂纳米颗粒。重要性声明：由于再矿化和抗菌特性，在酸蚀牙本质上应用锌掺杂纳米颗粒可减少树脂 - 牙本质界面的生物膜形成和活力。多西环素掺杂纳米颗粒也降低了口腔生物膜的活力，但未使树脂 - 牙本质界面再矿化。
