Mineral deposition promoted by resin-based sealants with different calcium phosphate additions

Abstract The aim of this study was to evaluate the influence of different calcium phosphates (CaPs) on the physical, biological, and remineralizing properties of experimental resin-based sealants (RBSs). Triethylene-glycol dimethacrylate (90wt%) and bisphenol A-glycidyl methacrylate (10wt%) were used to produce resin-based sealants. Hydroxyapatite (SHAp), α-tricalcium phosphate (Sα-TCP) and octacalcium phosphate (SOCP) were added to the sealants in a 10wt% concentration. One group without CaPs was used as the control group (SCG). The degree of conversion (DC) was assessed with Fourier-transformed infrared spectroscopy, whereas cytotoxicity was tested with the HaCaT keratinocyte cell line. The ultimate tensile strength (UTS) was used to assess the mechanical strength of the experimental RBSs. Sealed enamel was used for colorimetric assay. Mineral deposition was assessed with Raman spectroscopy after 7, 14, and 28 days of sample immersion in artificial saliva. Scanning electron microscopy was used to analyze the surface morphology after 28 days of immersion. The addition of 10wt% of fillers significantly reduced the DC of sealants. SOCP groups showed reduced cell viability. Higher UTS was found for Sα-TCP and SHAp. The color analysis showed that SGC and demineralized teeth presented higher mismatches with the sound tissue. Mineral deposition was observed for SHAp and Sα-TCP after 7 days, with increased phosphate content and mineral deposits for SHAp after 28 days. RBS with the addition of 10% HAp promoted increased mineralization in vitro after 28 days, and did not affect cell viability, DC, mechanical properties, or RBS color in the enamel.

摘要 本研究旨在评估不同磷酸钙（calcium phosphates, CaPs）对实验性树脂基封闭剂（resin-based sealants, RBSs）的物理、生物学及再矿化性能的影响。实验采用三乙二醇二甲基丙烯酸酯（90wt%）与双酚A-缩水甘油基甲基丙烯酸酯（10wt%）制备树脂基封闭剂，并分别添加10wt%浓度的羟基磷灰石（hydroxyapatite, SHAp）、α-磷酸三钙（α-tricalcium phosphate, Sα-TCP）与磷酸八钙（octacalcium phosphate, SOCP）；另设不含磷酸钙的组别作为对照组（SCG）。采用傅里叶变换红外光谱（Fourier-transformed infrared spectroscopy）检测转化率（degree of conversion, DC），以HaCaT角质形成细胞系开展细胞毒性测试，通过极限拉伸强度（ultimate tensile strength, UTS）评估实验性树脂基封闭剂的机械强度，以封闭后的牙釉质样本进行比色分析。将样本浸泡于人工唾液中7、14、28天后，借助拉曼光谱（Raman spectroscopy）检测矿物沉积情况；浸泡28天后采用扫描电子显微镜（scanning electron microscopy）分析样本表面形貌。
结果显示：添加10wt%的填料可显著降低封闭剂的转化率；磷酸八钙组的细胞存活率有所下降；α-磷酸三钙组与羟基磷灰石组的极限拉伸强度更高；比色分析表明，对照组与脱矿牙齿样本与健康牙体组织的颜色匹配度更低；浸泡7天后即可在羟基磷灰石组与α-磷酸三钙组中观察到矿物沉积，28天后羟基磷灰石组的磷酸盐含量与矿物沉积量进一步提升。添加10%羟基磷灰石的树脂基封闭剂在28天后可促进体外矿化，且不会影响细胞存活率、转化率、机械性能或牙釉质用树脂基封闭剂的颜色。