Department of Dental Materials, School of Dentistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
Cosmetology and Pharmaceutical Nanotechnology Laboratory, School of Pharmaceutical Sciences, Universidade Federal do Rio Grande do Sul, Av. Ipiranga 2752, 90610-000 Porto Alegre, RS, Brazil.
Dent Mater. 2023 Sep;39(9):839-845. doi: 10.1016/j.dental.2023.07.006. Epub 2023 Jul 26.
This study aims to formulate metronidazole liquid nanocapsules (MTZ) and evaluate their effect on the physicochemical and biological properties of calcium silicate-based bioactive endodontic cements, in vitro.
A MTZ suspension was formulated by deposition of the preformed polymer and characterized by laser diffraction and high-performance liquid chromatography (HPLC). Calcium silicate (CS) was mixed with a radiopaque agent (calcium tungstate - CaWO), at 10 wt%, to produce the cement powder. Cements liquids were used with two concentrations of MTZ suspension: 0.3 mg/ml and 0.15 mg/ml. Cements prepared with distilled water were used as the control. The radiopacity, setting time, and flow were evaluated following ISO 6876:2012. The compressive strength analysis was conducted according to ISO 9917:2007. pH and mineral deposition were evaluated after immersion in simulated body fluid (SBF). Cell behavior was evaluated by the viability of pre-osteoblastic cells and pulp fibroblasts by SRB and MTT and the antibacterial activity against Enterococcus faecalis was analyzed immediately and after nine months of water storage.
MTZ were formulated with a median diameter of 148 nm and 83.44 % load efficiency. Increased flow and reduced strength were observed for both MTZ concentrations. The incorporation of MTZ maintained the ability of cements to increase pH media and promote mineral deposition over the samples, without promoting cytotoxicity. A 2 log reduction in E. faecalis CFU was observed immediately and after nine months in water storage.
The formulation of MTZ allowed the development of antibacterial calcium silicate-based-cements with suitable physicochemical properties and bioactivity, with a reduction in mechanical strength. The 0.3 mg/ml concentration in cements liquid promoted effective and sustainable antibacterial activity.
本研究旨在制备甲硝唑液体纳米胶囊（MTZ），并评估其对基于硅酸钙的生物活性根管水泥的理化和生物学性质的影响，体外。
通过沉积预成型聚合物来制备 MTZ 混悬液，并通过激光衍射和高效液相色谱（HPLC）进行表征。将硅酸钙（CS）与放射性造影剂（钨酸钙-CaWO）以 10wt%的比例混合，制成水泥粉末。使用两种浓度的 MTZ 混悬液（0.3mg/ml 和 0.15mg/ml）制备水泥液。以蒸馏水为对照。按照 ISO 6876:2012 评估放射密度、凝固时间和流动性。根据 ISO 9917:2007 进行抗压强度分析。在模拟体液（SBF）中浸泡后评估 pH 值和矿物质沉积。通过 SRB 和 MTT 评估骨髓间充质干细胞和成纤维细胞的活力，分析对粪肠球菌的抗菌活性，并在水储存 9 个月后进行分析。
MTZ 的粒径为 148nm，载药量为 83.44%。两种 MTZ 浓度均观察到流动性增加和强度降低。MTZ 的掺入保持了水泥提高 pH 介质和促进矿物质沉积的能力，而没有促进细胞毒性。粪肠球菌 CFU 立即减少 2 个对数级，在水储存 9 个月后也减少 2 个对数级。
MTZ 的配方允许开发具有合适理化性质和生物活性的抗菌硅酸钙基水泥，同时降低机械强度。水泥液中 0.3mg/ml 的浓度可促进有效且可持续的抗菌活性。
