Iran Polymer and Petrochemical Institute (IPPI), P.O. Box 14965/115, Tehran, Iran.
Iran Polymer and Petrochemical Institute (IPPI), P.O. Box 14965/115, Tehran, Iran.
J Mech Behav Biomed Mater. 2023 Mar;139:105693. doi: 10.1016/j.jmbbm.2023.105693. Epub 2023 Jan 30.
Considering the poor hydrolytic stability of the most methacrylate-based functional monomers of self-etch dental adhesives in acidic and aqueous conditions, in this study allyl-based photo-polymerizable self-etch monomers was synthesized in order to improve the hydrolytic stability. The new self-etch monomers based on phosphonic acid functional groups were synthesized through a two-step procedure. First, phosphoric anhydride, poly-phosphoric acid, and polyethylene glycol were reacted to produce phosphate ester precursor (P-PEG-P). Next, allyl 2, 3-epoxypropyl ether was reacted with P-PEG-P to synthesize allyl self-etch monomer. Glycidyl methacrylate was also reacted with P-PEG-P to synthesize a methacrylate self-etch analogue monomer. The monomers were characterized using FTIR and 1H-NMR spectroscopy. The viscosities of monomers were measured using a rheometer. The degree photopolymerization conversion of monomers was measured using FTIR spectroscopy. The pH assay was performed by a digital pH-meter. The etching behavior of the monomers on human teeth was studied using scanning electron microscopy (SEM). Thermo-gravimetric analysis (TGA) was performed to evaluate the possible interaction of the monomers with tricalcium phosphate (TCP). The solubility of synthesized monomers was examined in ethanol, acetone, and water. The hydrolytic stability of cured resins in artificial saliva during 4 months was also surveyed. The synthesis of new self-etching monomers was successfully confirmed by spectroscopy analyses. The results represented appropriate viscosity of self-etching monomers around 1 (Pa s). The resin containing methacrylate monomer exhibited its degree of conversion is more than that of allyl monomer (p < 0.05). The allyl and methacrylate self-etch monomers exhibited pH values of 1.2 and 1.3, respectively. SEM micrograph verified that the synthesized monomers were able to suitable etching of the enamel human premolar teeth. The data obtained from TGA tests revealed that thermal stability of (TCP) containing monomers is enhanced. Also, the monomers exhibited an excellent solubility in polar solvents, but when they are mixed with TCP, they are not, anymore, dissolved in these solvents. Furthermore, the allyl monomer showed higher hydrolytic stability than the methacrylate monomer. The new photo-polymerizable acidic monomer based on allyl functionality showed enhanced hydrolytic stability compared to methacrylate-based monomer. It may be considered as a promising monomer for self-etch dental adhesives.
考虑到大多数自酸蚀牙科粘接剂的甲基丙烯酰基功能性单体在酸性和水性条件下水解稳定性差，本研究合成了基于烯丙基的光聚合自酸蚀单体，以提高水解稳定性。通过两步法合成了基于膦酸官能团的新型自酸蚀单体。首先，磷酸酐、多聚磷酸和聚乙二醇反应生成磷酸酯前体（P-PEG-P）。然后，烯丙基 2,3-环氧丙基醚与 P-PEG-P 反应合成烯丙基自酸蚀单体。甲基丙烯酸缩水甘油酯也与 P-PEG-P 反应合成甲基丙烯酸自酸蚀类似物单体。单体用 FTIR 和 1H-NMR 光谱进行表征。用流变仪测量单体的粘度。用 FTIR 光谱法测量单体的光聚合转化率。用数字 pH 计进行 pH 测定。用扫描电子显微镜（SEM）研究单体对人牙的蚀刻行为。用热重分析（TGA）评估单体与磷酸三钙（TCP）的可能相互作用。考察合成单体在乙醇、丙酮和水中的溶解度。还在人工唾液中对固化树脂进行了 4 个月的水解稳定性研究。通过光谱分析成功证实了新自酸蚀单体的合成。结果表明，自酸蚀单体的粘度在 1（Pa s）左右。含甲基丙烯酸单体的树脂的转化率大于烯丙基单体（p < 0.05）。烯丙基和甲基丙烯酸自酸蚀单体的 pH 值分别为 1.2 和 1.3。SEM 显微照片证实，合成单体能够对人前磨牙釉质进行适当的蚀刻。TGA 测试数据显示，含单体的（TCP）热稳定性增强。此外，单体在极性溶剂中具有优异的溶解性，但当与 TCP 混合时，它们不再溶解在这些溶剂中。此外，烯丙基单体的水解稳定性高于甲基丙烯酸单体。基于烯丙基功能的新型光聚合酸性单体与基于甲基丙烯酸的单体相比，水解稳定性增强。它可以被认为是一种有前途的自酸蚀牙科胶粘剂单体。
