Department of Developmental Dentistry, Medical University of Lodz, Lodz, Poland.
Med Sci Monit. 2011 Aug;17(8):BR201-208. doi: 10.12659/msm.881898.
Monomers of methacrylates used in restorative dentistry have been recently reported to induce DNA double-strand breaks (DSBs) in human gingival fibroblasts (HGFs) in vitro. Because such monomers may penetrate the pulp and oral cavity due to the incompleteness of polymerization and polymer degradation, they may induce a similar effect in vivo. DSBs are the most serious type of DNA damage and if misrepaired or not repaired may lead to mutation, cancer transformation and cell death. Therefore, the protection against DSBs induced by methacrylate monomers released from dental restorations is imperative.
MATERIAL/METHODS: We examined the protective action of chitosan oligosaccharide lactate (ChOL) against cytotoxic and genotoxic effects induced by monomers of the model adhesive consisting of 55% bisphenol A-diglycidyl dimethacrylate (Bis-GMA) and 45% 2-hydroxyethyl methacrylate (HEMA). We evaluated the extent of DSBs by the neutral comet assay and the phosphorylation of the H2AX histone test.
ChOL increased the viability of HGFs exposed to Bis-GMA/HEMA as assessed by flow cytometry. ChOL decreased the extent of DSBs induced by Bis-GMA/HEMA as evaluated by neutral comet assay and phosphorylation of the H2AX histone. ChOL did not change mechanical properties of the model adhesive, as checked by the shear bond test. Scanning electron microscopy revealed a better sealing of the dentinal microtubules in the presence of ChOL, which may protect pulp cells against the harmful action of the monomers.
ChOL can be considered as an additive to methacrylate-based dental materials to prevent DSBs induction, but further studies are needed on its formulation with the methacrylates.
用于修复牙科的甲基丙烯酸酯单体最近被报道在体外诱导人牙龈成纤维细胞（HGFs）的 DNA 双链断裂（DSBs）。由于聚合不完全和聚合物降解，这些单体可能会穿透牙髓和口腔，因此它们可能会在体内产生类似的影响。DSBs 是最严重的 DNA 损伤类型，如果不能正确修复或不修复，可能会导致突变、癌症转化和细胞死亡。因此，防止牙科修复体释放的甲基丙烯酸酯单体引起的 DSBs 至关重要。
材料/方法：我们研究了壳寡糖乳酸盐（ChOL）对由 55%双酚 A 二缩水甘油二甲基丙烯酸酯（Bis-GMA）和 45% 2-羟乙基甲基丙烯酸酯（HEMA）组成的模型粘合剂单体诱导的细胞毒性和遗传毒性的保护作用。我们通过中性彗星试验和 H2AX 组蛋白磷酸化试验评估 DSBs 的程度。
ChOL 通过流式细胞术增加了暴露于 Bis-GMA/HEMA 的 HGFs 的活力。ChOL 通过中性彗星试验和 H2AX 组蛋白磷酸化试验降低了 Bis-GMA/HEMA 诱导的 DSBs 的程度。ChOL 没有改变模型粘合剂的力学性能，通过剪切结合试验进行了检查。扫描电子显微镜显示，在存在 ChOL 的情况下，牙本质微管的密封更好，这可能保护牙髓细胞免受单体的有害作用。
ChOL 可以被认为是甲基丙烯酸酯基牙科材料的添加剂，以防止 DSBs 的诱导，但需要进一步研究其与甲基丙烯酸酯的配方。
