Objective

The use of resin cements in clinical practice entails photopolymerization through prosthetic devices, which precludes light penetration. The objective of this study was to modify experimental resin cements (ERCs) with diphenyliodonium hexafluorophosphate (DPI) in an attempt to improve chemical and mechanical properties of materials cured with reduced irradiance and final radiant exposure.

Methods

A co-monomer base containing a 1:1 mass ratio of 2.2-bis[4-(2-hydroxy-3-methacryloxypropoxy)phenyl]propane (bis-GMA) and triethyleneglycol dimethacrylate (TEGDMA) was prepared, with 1 mol% of camphorquinone and 2 mol% of ethyl 4-(dimethylamino)benzoate as initiator system. The resin was divided into 4 fractions according to the DPI concentrations (0, 0.5, 1 and 2 mol%). The challenging polymerization condition was simulated performing the light activation (12, 23 and 46 s) through a ceramic block (3 mm thick). The irradiance was assessed with a calibrated spectrometer (1320 mW/cm²), resulting in three levels of radiant exposure (0.58, 1.1 and 2.2 J/cm²). The polymerization kinetics was evaluated in real-time using a spectrometer (Near-IR). Water sorption and solubility was analyzed and the cohesive strength of resins obtained through the microtensile test. Polymerization stress was assessed by Bioman method.

Results

Resins containing DPI had higher degree of conversion and rate of polymerization than the control (without DPI). The use of DPI reduced water sorption and solubility, and led to higher cohesive strength compared to resins without the iodonium salt. However, the stress of polymerization was higher for experimental resins with DPI.

Significance

Even under remarkably reduced irradiance, cements containing a ternary initiating system with an iodonium salt can present an optimal degree of conversion and chemical/mechanical properties.

中文翻译：

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在具有挑战性的聚合条件下固化的含有碘盐的实验树脂粘固剂的性能改进

客观的

在临床实践中使用树脂水门汀需要通过假体装置进行光聚合，这会阻止光线穿透。本研究的目的是用六氟磷酸二苯基碘鎓 (DPI) 改性实验树脂粘固剂 (ERC)，以尝试改善在降低辐照度和最终辐射暴露的情况下固化材料的化学和机械性能。

方法

制备含有质量比为 1:1 的 2.2-双[4-(2-羟基-3-甲基丙烯酰氧基丙氧基)苯基]丙烷 (bis-GMA) 和三乙二醇二甲基丙烯酸酯 (TEGDMA) 的共聚单体基料，其中 1  mol%樟脑醌和 2  mol% 的 4-（二甲氨基）苯甲酸乙酯作为引发剂体系。根据 DPI 浓度（0、0.5、1 和 2  mol%）将树脂分成 4 个部分。模拟具有挑战性的聚合条件， 通过陶瓷块（3 毫米厚）进行光活化（12、23 和 46秒）。辐照度是用校准的光谱仪 (1320  mW/cm ² )评估的，产生三个辐射暴露水平 (0.58、1.1 和 2.2  J/cm ²）。使用光谱仪（近红外）实时评估聚合动力学。分析了吸水性和溶解性，并通过微拉伸试验获得了树脂的内聚强度。通过Bioman方法评估聚合应力。

结果

含有 DPI 的树脂比对照（不含 DPI）具有更高的转化率和聚合速率。与不含碘鎓盐的树脂相比，DPI 的使用降低了水的吸附性和溶解性，并导致更高的内聚强度。然而，使用 DPI 的实验树脂的聚合应力更高。

意义

即使在显着降低的辐照度下，含有碘鎓盐三元引发系统的水泥也能呈现最佳的转化率和化学/机械性能。