Toledano M, Aguilera F-S, Cabello I, Toledano-Osorio M, Osorio E, López-López M-T, García-Godoy F, Lynch C-D, Osorio R
University of Granada, Faculty of Dentistry, Colegio Máximo de Cartuja s/n, 18071, Granada, Spain,
Med Oral Patol Oral Cir Bucal. 2019 Mar 1;24(2):e156-e164. doi: 10.4317/medoral.22885.
The aim was to evaluate the effect of silver loaded nanoparticles (NPs) application on the triboscopic, crystallographic and viscoelastic properties of demineralized dentin. Polymethylmetacrylate-based NPs and Ag loaded NPs were applied on demineralized dentin.
Treated and untreated surfaces were probed by a nanoindenter to test viscoelasticity, and by atomic force microscopy to test nanoroughness and collagen fibril diameter. X-ray diffraction and transmission electron microscopy through selected area diffraction and bright-field imaging were also used.
Dentin treated with Ag-NPs attained the lowest complex modulus, and the highest tan delta values after 7 days of storage. Dentin treated with undoped-NPs achieved the lowest nanoroughness and the greatest collagen bandwidths among groups. Crystals were identified as hydroxyapatite with the highest crystallographic maturity and crystallite size in dentin treated with undoped-NPs. Texture increased in all samples from 24 h to 7 d, except in dentin surfaces treated with Ag-NPs at 310 plane. Polyhedral, block-like, hexagonal or plate-like shaped apatite crystals constituted the bulk of minerals in dentin treated with Ag-NPs, after 7 d. Polyhedral or rounded/drop-like, and polymorphic in strata crystal apatite characterized the minerals when undoped-NPs were used, with more crystalline characteristics after 7 d than that found when Ag-NPs were applied. Ag-NPs application did not improve the mechanical performance of dentin and did not produce dentin remineralization. However, energy was dissipated through the dentin without showing stress concentration; contrary was occurring at dentin treated with undoped-NPs, that provoked bridge-like mineral deposits at the dentin surface.
Ag-NPs application did not enhance the mechanical properties of cervical dentin, though the energy dissipation did not damage the dentin structure. Remineralization at dentin was not produced after Ag-NPs application, though improved crystallinity may lead to increase stability of the apatite that was generated at the dentin surface.
目的是评估负载银的纳米颗粒（NPs）应用于脱矿牙本质的摩擦学、晶体学和粘弹性特性的影响。将基于聚甲基丙烯酸甲酯的NPs和负载银的NPs应用于脱矿牙本质。
通过纳米压痕仪探测处理过和未处理的表面以测试粘弹性，通过原子力显微镜测试纳米粗糙度和胶原纤维直径。还使用了X射线衍射以及通过选区衍射和明场成像的透射电子显微镜。
用银纳米颗粒处理的牙本质在储存7天后获得了最低的复数模量和最高的损耗角正切值。在各组中，用未掺杂纳米颗粒处理的牙本质具有最低的纳米粗糙度和最大的胶原带宽。在用未掺杂纳米颗粒处理的牙本质中，晶体被鉴定为具有最高晶体成熟度和微晶尺寸的羟基磷灰石。除了在310平面用银纳米颗粒处理的牙本质表面外，所有样品从24小时到7天的织构都增加了。7天后，在用银纳米颗粒处理的牙本质中，多面体、块状、六边形或板状的磷灰石晶体构成了大部分矿物质。当使用未掺杂纳米颗粒时，多面体或圆形/滴状以及地层晶体磷灰石的多晶型物表征了矿物质，7天后比应用银纳米颗粒时具有更多的晶体特征。应用银纳米颗粒并未改善牙本质的机械性能，也未产生牙本质再矿化。然而，能量通过牙本质耗散而未显示出应力集中；在用未掺杂纳米颗粒处理的牙本质中则相反，在牙本质表面引发了桥状矿物质沉积。
应用银纳米颗粒并未增强颈部牙本质的机械性能，尽管能量耗散并未损害牙本质结构。应用银纳米颗粒后牙本质未发生再矿化，尽管结晶度的提高可能导致牙本质表面生成的磷灰石稳定性增加。
