Weintraub Center for Reconstructive Biotechnology, Division of Regenerative and Reconstructive Sciences, UCLA School of Dentistry, Los Angeles, CA 90095, USA.
Int J Mol Sci. 2022 Dec 14;23(24):15869. doi: 10.3390/ijms232415869.
The fibroblast-rich gingival tissue is usually in contact with or adjacent to cytotoxic polymer-based dental restoration materials. The objective of this study was to determine whether the antioxidant amino acid, N-acetyl cysteine (NAC), reduces the toxicity of dental restorative materials. Human oral fibroblasts were cultured with bis-acrylic, flowable composite, bulk-fill composite, self-curing acrylic, and titanium alloy test specimens. Cellular behavior and function were analyzed on and around the materials. Impregnation of the bulk-fill composite and self-curing acrylic with NAC reduced their toxicity, improving the attachment, growth, and function of human oral fibroblasts on and around the materials. These mitigating effects were NAC dose dependent. However, NAC impregnation of the bis-acrylic and flowable composite was ineffective, with no cells attaching to nor around the materials. Although supplementing the culture medium with NAC also effectively improved fibroblast behaviors, direct impregnation of materials with NAC was more effective than supplementing the cultures. NAC-mediated improvements in fibroblast behavior were associated with reduced production of reactive oxygen species and oxidized glutathione together with increased glutathione reserves, indicating that NAC effectively directly scavenged ROS from materials and reinforced the cellular antioxidant defense system. These results establish a proof of concept of NAC-mediated improvements in biocompatibility in the selected dental restorative materials.
富含成纤维细胞的牙龈组织通常与细胞毒性聚合物基牙科修复材料接触或相邻。本研究的目的是确定抗氧化氨基酸 N-乙酰半胱氨酸 (NAC) 是否能降低牙科修复材料的毒性。将人口腔成纤维细胞与双丙烯酸酯、流动性复合树脂、块状填充复合树脂、自固化丙烯酸酯和钛合金试件一起培养。分析了材料上和周围的细胞行为和功能。将块状填充复合树脂和自固化丙烯酸酯用 NAC 浸渍可降低其毒性，改善人口腔成纤维细胞在材料上和周围的附着、生长和功能。这些缓解作用与 NAC 剂量有关。然而，双丙烯酸酯和流动性复合树脂的 NAC 浸渍无效，材料周围没有细胞附着。虽然向培养基中补充 NAC 也能有效地改善成纤维细胞的行为，但直接用 NAC 浸渍材料比补充培养物更有效。NAC 介导的成纤维细胞行为的改善与活性氧和氧化型谷胱甘肽的产生减少以及谷胱甘肽储备的增加有关，这表明 NAC 能有效地从材料中直接清除 ROS，并增强细胞抗氧化防御系统。这些结果为 NAC 介导的所选牙科修复材料的生物相容性改善提供了概念验证。
