Becaria CONICET, Facultad de Ciencias de la Salud, Universidad Católica de Córdoba, Córdoba, Argentina.
Facultad de Ciencias de la Salud, Universidad Católica de Córdoba, Córdoba, Argentina.
Sci Rep. 2023 Nov 30;13(1):21126. doi: 10.1038/s41598-023-48519-1.
The aims of this study were: To evaluate the surface hardness of simulated dentin caries lesions treated with either silver nanoclusters (AgNCls) synthesized in polymethacrylic acid (PMAA) or 38% silver diammine fluoride (SDF), as well as observe the penetration of the treatment solutions into the simulated caries lesions. Dentin blocks 4 mm thick obtained from caries-free third molars were sectioned and then simulated caries lesions on the occlusal dentin surfaces were created. Each specimen (n = 8) was divided into four sections: (A) treated with 20% AgNCls/PMAA; (B) treated with SDF 38% (FAgamin, Tedequim, Cordoba, Argentina); (C) sound tooth protected by nail-varnish during artificial caries generation (positive control); and (D) artificial caries lesion without surface treatment (negative control). AgNCls/PMAA or SDF were applied on the simulated lesions with a microbrush for 10 s, then excess removed. The surface hardness was measured by means of Vickers indentation test. To trace the depth of penetration, up to 400 μm, of silver ions, elemental composition of the samples was observed using EDX, coupled with SEM, and measured every 50 μm from the surface towards the pulp chamber. Laser Induced Breakdown Spectroscopy (LIBS) was also employed to trace silver ion penetration; the atomic silver line 328.06 nm was used with a 60 μm laser spot size to a depth of 240 μm. Student's-t test identified significant differences between treatment groups for each depth and the Bonferroni test was used for statistical analysis of all groups (p < 0.05). Mean surface hardness values obtained were 111.2 MPa, 72.3 MPa, 103.3 MPa and 50.5 MPa for groups A, B, C and D respectively. There was a significant difference between groups A and C compared with groups B and D, the group treated with AgNCls/PMAA achieved the highest surface hardness, similar or higher than the sound dentin control. A constant presence of silver was observed throughout the depth of the sample for group A, while group B showed a peak concentration of silver at the surface with a significant drop beyond 50 μm. The 20% AgNCls/PMAA solution applied to simulated dentin caries lesions achieved the recovery of surface hardness equivalent to sound dentin with the penetration of silver ions throughout the depth of the lesion.
评估用合成于聚甲基丙烯酸（PMAA）中的银纳米簇（AgNCls）或 38%氟化银胺（SDF）处理模拟牙本质龋损的表面硬度，并观察治疗溶液渗透入模拟龋损的情况。从无龋第三磨牙获得 4mm 厚的牙本质块，然后在牙合面牙本质表面制备模拟龋损。每个标本（n=8）分为四部分：（A）用 20%AgNCls/PMAA 处理；（B）用 38% SDF（Tedequim，Córdoba，阿根廷）处理；（C）在人工龋生成期间用指甲油保护的健康牙齿（阳性对照）；（D）未经表面处理的人工龋损（阴性对照）。用微型刷子将 AgNCls/PMAA 或 SDF 涂在模拟病变上 10 秒，然后去除多余的部分。通过维氏压痕试验测量表面硬度。为了追踪银离子的渗透深度，高达 400μm，使用 EDX 结合 SEM 观察样品的元素组成，并从表面向牙髓腔每 50μm 测量一次。还使用激光诱导击穿光谱（LIBS）追踪银离子的渗透；使用 60μm 的激光光斑大小和 328.06nm 的原子银线，可探测 240μm 的深度。学生 t 检验确定了各组在每个深度的治疗组之间的显著差异，并用 Bonferroni 检验对所有组进行统计分析（p<0.05）。分别为 A、B、C 和 D 组的表面硬度平均值为 111.2MPa、72.3MPa、103.3MPa 和 50.5MPa。与 B 和 D 组相比，A 组和 C 组之间有显著差异，用 AgNCls/PMAA 处理的组获得的表面硬度最高，与健康牙本质相似或更高。在 A 组的样品深度中观察到银的恒定存在，而 B 组在表面处显示出银的峰值浓度，超过 50μm 后显著下降。将 20%AgNCls/PMAA 溶液应用于模拟牙本质龋损可恢复与健康牙本质相当的表面硬度，同时银离子渗透到病变的整个深度。
