In the case of dental pulp exposure, direct pulp capping is often performed to preserve vital dental pulp tissue. Numerous studies regarding the development of direct pulp-capping materials have been conducted, but materials with an appropriate sealing ability, which induce dense reparative dentin formation, have not been developed. Although nano hydroxyapatite (naHAp) is a bone-filling material with bioactivity and biocompatibility, the inductive effects of naHAp on reparative dentin formation remain unclear. In the present study, the effects of dental adhesive material 4-methacryloxyethyl trimellitate anhydride/methyl methacrylate tri-n-butylborane [4-META/MMA-TBB or Super-bond (SB)], which included 10%, 30%, and 50% naHAp (naHAp/SB) on odontoblastic differentiation of dental pulp stem cells (DPSCs) and reparative dentin formation were investigated. Scanning electron microscopy (SEM) and energy dispersive X-ray spectrometer analysis were performed to verify the existence of naHAp particles on the surface of naHAp/SB discs. The tensile adhesive strength of naHAp/SB was measured using a universal testing machine. As a result, 10% naHAp/SB and 30% naHAp/SB showed almost the same tensile adhesive strength as SB but 50% naHAp/SB showed significantly lower than the other experimental group. WST-1 proliferation assay and SEM analysis revealed that naHAp/SB did not affect the proliferation of DPSCs. Calcium release assay, quantitative RT-PCR, and western blotting analysis demonstrated that naHAp/SB did not release calcium ion but 30% naHAp/SB increased the expression of calcium-sensing receptor (CaSR) in DPSCs. Additionally, quantitative RT-PCR, western blotting analysis, Alizarin Red S- and von Kossa staining revealed that 30% naHAp/SB induced odontoblastic differentiation of DPSCs, which was inhibited by a MEK/ERK inhibitor and CaSR antagonist. Furthermore, 30% naHAp/SB promoted dense reparative dentin formation in an experimentally-formed rat dental pulp exposure model. These findings suggest that 30% naHAp/SB can be used as an ideal direct pulp capping material.

在牙髓暴露的情况下，通常进行直接盖髓以保护重要的牙髓组织。已经进行了大量关于开发直接盖髓材料的研究，但尚未开发出具有适当封闭能力的材料，从而诱导致密的修复牙本质的形成。尽管纳米羟基磷灰石 (naHAp) 是一种具有生物活性和生物相容性的骨填充材料，但 naHAp 对修复性牙本质形成的诱导作用仍不清楚。在本研究中，牙科粘合剂材料 4-甲基丙烯酰氧基乙基偏苯三酸酐/甲基丙烯酸甲酯三正丁基硼烷 [4-META/MMA-TBB 或 Super-bond (SB)] 的影响，其中包括 10%、30%、研究了 50% naHAp (naHAp/SB) 对牙髓干细胞 (DPSC) 的成牙本质细胞分化和修复性牙本质形成的影响。进行扫描电子显微镜 (SEM) 和能量色散 X 射线光谱仪分析以验证 naHAp/SB 盘表面上 naHAp 颗粒的存在。naHAp/SB 的拉伸粘合强度使用万能试验机测量。结果，10% naHAp/SB 和 30% naHAp/SB 显示出与 SB 几乎相同的拉伸粘合强度，但 50% naHAp/SB 显示出显着低于其他实验组。WST-1 增殖试验和 SEM 分析表明 naHAp/SB 不影响 DPSCs 的增殖。钙释放测定，定量 RT-PCR，蛋白质印迹分析表明，naHAp/SB 不释放钙离子，但 30% naHAp/SB 增加了 DPSCs 中钙敏感受体 (CaSR) 的表达。此外，定量 RT-PCR、蛋白质印迹分析、茜素红 S- 和 von Kossa 染色显示 30% naHAp/SB 诱导 DPSCs 的成牙本质细胞分化，这被 MEK/ERK 抑制剂和 CaSR 拮抗剂抑制。此外，在实验形成的大鼠牙髓暴露模型中，30% naHAp/SB 促进了致密修复性牙本质的形成。这些发现表明 30% naHAp/SB 可用作理想的直接盖髓材料。茜素红 S- 和 von Kossa 染色显示 30% naHAp/SB 诱导 DPSCs 的成牙本质细胞分化，这被 MEK/ERK 抑制剂和 CaSR 拮抗剂抑制。此外，在实验形成的大鼠牙髓暴露模型中，30% naHAp/SB 促进了致密修复性牙本质的形成。这些发现表明 30% naHAp/SB 可用作理想的直接盖髓材料。茜素红 S- 和 von Kossa 染色显示 30% naHAp/SB 诱导 DPSCs 的成牙本质细胞分化，这被 MEK/ERK 抑制剂和 CaSR 拮抗剂抑制。此外，在实验形成的大鼠牙髓暴露模型中，30% naHAp/SB 促进了致密修复性牙本质的形成。这些发现表明 30% naHAp/SB 可用作理想的直接盖髓材料。