University of Granada, Department of Stomatology, Colegio Máximo de Cartuja s/n, Granada 18071, Spain.
University of Granada, Department of Stomatology, Colegio Máximo de Cartuja s/n, Granada 18071, Spain.
Dent Mater. 2021 Nov;37(11):1698-1713. doi: 10.1016/j.dental.2021.09.001. Epub 2021 Sep 17.
To investigate the effect of novel polymeric nanoparticles (NPs) doped with melatonin (ML) on nano-hardness, crystallinity and ultrastructure of the formed hydroxyapatite after endodontic treatment.
Undoped-NPs and ML-doped NPs (ML-NPs) were tested at radicular dentin, after 24 h and 6 m. A control group without NPs was included. Radicular cervical and apical dentin surfaces were studied by nano-hardness measurements, X-ray diffraction and transmission electron microscopy. Mean and standard deviation were analyzed by ANOVA and Student-Newman-Keuls multiple comparisons (p < 0.05).
Cervical dentin treated with undoped NPs maintained its nano-hardness values after 6 m of storage being [24 h: 0.29 (0.01); 6 m: 0.30 (0.02) GPa], but it decreased at apical dentin [24 h: 0.36 (0.01); 6 m: 0.28 (0.02) GPa]. When ML-NPs were used, nano-hardness was similar over time [24h: 0.31 (0.02); 6 m: 0.28 (0.03) GPa], at apical dentin. Root dentin treated with ML-NPs produced, in general, high crystallinity of new minerals and thicker crystals than those produced in the rest of the groups. After 6 m, crystals became organized in randomly oriented polyhedral, square polygonal block-like apatite or drop-like apatite polycrystalline lattices when ML-NPs were used. Undoped NPs generated poor crystallinity, with preferred orientation of small crystallite and increased microstrain.
New polycrystalline formations encountered in dentin treated with ML-NPs may produce structural dentin stability and high mechanical performance at the root. The decrease of mechanical properties over time in dentin treated without NPs indicates scarce remineralization potential, dentin demineralization and further potential degradation. The amorphous stage may provide high hydroxyapatite solubility and remineralizing activity.
研究新型聚合物纳米粒子（NPs）掺杂褪黑素（ML）对根管治疗后形成的羟基磷灰石的纳米硬度、结晶度和超微结构的影响。
在根管牙本质上测试未掺杂 NPs 和 ML 掺杂 NPs（ML-NPs），时间分别为 24 h 和 6 m。还包括一个无 NPs 的对照组。通过纳米硬度测量、X 射线衍射和透射电子显微镜研究根颈和根尖牙本质表面。用方差分析和 Student-Newman-Keuls 多重比较（p < 0.05）分析平均值和标准差。
用未掺杂 NPs 处理的牙本质在储存 6 m 后保持其纳米硬度值不变，[24 h：0.29（0.01）；6 m：0.30（0.02）GPa]，但在根尖牙本质中下降[24 h：0.36（0.01）；6 m：0.28（0.02）GPa]。当使用 ML-NPs 时，纳米硬度在根尖牙本质上随时间保持相似[24 h：0.31（0.02）；6 m：0.28（0.03）GPa]。用 ML-NPs 处理的根牙本质一般产生新矿物质的高结晶度和比其他组更厚的晶体。6 m 后，当使用 ML-NPs 时，晶体形成随机取向的多面体形、方形多角块状磷灰石或滴状磷灰石多晶格子。未掺杂 NPs 生成结晶度差，具有小晶粒的择优取向和增加的微应变。
用 ML-NPs 处理的牙本质中遇到的新多晶形成可能会在根部产生结构牙本质稳定性和高机械性能。未用 NPs 处理的牙本质随时间机械性能下降表明再矿化潜力不足、牙本质脱矿化和进一步潜在降解。无定形阶段可能提供高的羟基磷灰石溶解度和再矿化活性。
