Objectives

This study evaluated the efficacy of a thiourethane(TU)-modified silane agent in improving properties in filled composites.

Methods

The TU-silane agent was synthesized by combining 1,3-bis(1-isocyanato-1-methylethyl)benzene and 3-(triethoxysilyl)propyl isocyanate with trimethylol-tris-3-mercaptopropionate (TMP), at 1:2 isocyanate:thiol, leaving pendant thiol and alkoxy silane groups. Barium glass fillers (1 μm average particle size) were functionalized with 5 wt% TU-silane in an acidic ethanol solution. Commercially available 3-(trimethoxysilyl)propyl methacrylate (MA-silane) and (3-mercaptopropyl)trimethoxysilane (SH-silane), as well as no silane treatment (NO-silane), were used as controls. Composites were made with BisGMA-UDMA-TEGDMA (5:3:2), camphorquinone/ethyl-4-dimethylaminobenzoate (0.2/0.8 wt%) and di-tert-butyl hydroxytoluene (0.3 wt%) and 70 wt% silanated inorganic fillers. Polymerization stress (PS) was measured using a cantilever beam apparatus (Bioman). Methacrylate conversion (DC) and rate of polymerization (RP) during photoactivation (800 mW/cm²) were followed in real-time with near-IR. Flexural strength/modulus (FS/FM) were evaluated in three-point bending with 2 × 2 × 25 mm. Statistical analysis: 2-way ANOVA/Tukey’s test (α = 5%).

Results

DC, Rp_max and E were similar for all groups tested. FS was similar for the TU- and MA-silane, which were statistically higher than the untreated and SH-silane groups. Stress reductions in relation to the MA-silane were observed for all groups, but statistically more markedly for the TU-silane material. This is likely due to stress relaxation and/or toughening provided at the filler interface by the oligomeric TU structure.

Significance

TU-silane oligomers favorably modified conventional dimethacrylate networks with minimal disruption to existing curing chemistry, in filled composites. For the same conversion values, stress reductions of up to 50% were observed, without compromise to mechanical properties or handling characteristics.

中文翻译：

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硫代氨基甲酸酯填料表面功能化对修复性牙科复合材料的应力，转化率和力学性能的影响

目标

这项研究评估了硫代氨基甲酸酯（TU）改性硅烷试剂在改善填充复合材料性能方面的功效。

方法

TU-硅烷试剂是通过将1,3-双（1-异氰酸根-1-甲基乙基）苯和3-（三乙氧基甲硅烷基）丙基异氰酸酯与三羟甲基-三-3-巯基丙酸酯（TMP）混合形成异氰酸酯：1：2硫醇，留下侧基硫醇和烷氧基硅烷基团。将钡玻璃填料（平均粒径为1μm）在酸性乙醇溶液中用5 wt％的TU-硅烷官能化。使用市售的甲基丙烯酸3-（三甲氧基甲硅烷基）丙酯（MA-硅烷）和（3-巯基丙基）三甲氧基硅烷（SH-硅烷），以及不进行硅烷处理（NO-硅烷）作为对照。，樟脑醌/乙基-4-二甲氨基苯甲酸酯（0.2 / 0.8重量％）和二-复合材料用的BisGMA-UDMA-TEGDMA（：3 2 5）由叔-丁基羟基甲苯（0.3 wt％）和70 wt％硅烷化的无机填料。使用悬臂梁装置（Bioman）测量聚合应力（PS）。使用近红外实时跟踪甲基丙烯酸酯的转化率（DC）和光活化过程中的聚合速率（RP）（800 mW / cm ²）。抗弯强度/模量（FS / FM）在2×2×25 mm的三点弯曲中进行评估。统计分析：2次方差分析/ Tukey检验（α  = 5％）。

结果

所有测试组的DC，Rp _max和E均相似。TU-和MA-硅烷的FS相似，统计上高于未处理的和SH-硅烷基团。在所有组中均观察到与MA-硅烷有关的应力降低，但在TU-硅烷材料上统计学上更为明显。这可能是由于低聚物TU结构在填料界面处提供了应力松弛和/或增韧。

意义

在填充的复合材料中，TU-硅烷低聚物可以很好地改性常规的二甲基丙烯酸酯网络，而对现有固化化学的破坏最小。对于相同的转换值，观察到应力降低高达50％，而不会影响机械性能或处理特性。