Shrinkage / stress reduction and mechanical properties improvement in restorative composites formulated with thio-urethane oligomers.
Shrinkage / stress reduction and mechanical properties improvement in restorative composites formulated with thio-urethane oligomers.
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DOI：
10.1016/j.jmbbm.2017.11.011
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发表时间：
2018-03
影响因子：
3.9
通讯作者：
Pfeifer CS
中科院分区：
文献类型：
--
作者：
Bacchi A;Yih JA;Platta J;Knight J;Pfeifer CS
硫代氨基甲酸酯低聚物（TU）已显示出有利地改性甲基丙烯酸酯网络以降低应力并显著增加断裂韧性。由于这些是牙科应用中非常理想的特征，因此本工作的目的是表征添加TU配制的修复复合材料。通过将硫醇-季戊四醇四-3-巯基丙酸酯（PETMP）或正-三-3-巯基丙酸酯（TMP）-与异氰酸酯-1，6-己二醇二异氰酸酯（HDDI）（脂肪族）或1，3-双（1-异氰酸基-1-甲基乙基）苯（BDI）（芳香族）或二环己基甲烷4，4 ′-二异氰酸酯（HMDI）（环状）以1：2的异氰酸酯：硫醇组合来合成TU，留下侧基硫醇。将20重量% TU加入到BisGMA-TEGDMA（70-30%）中。向该有机基质中加入70重量%的硅烷化无机填料。近红外用于跟踪甲基丙烯酸酯转化率和聚合速率（Rpmax）。在三点弯曲（ISO 4049）中评价机械性能的弯曲强度/模量（FS/FM）和韧性（T），并在缺口试样（ASTM标准E399-90）中评价断裂韧性（KIC）。在Bioman上测量聚合应力（PS）。体积收缩率（VS）的测定与粘结盘技术。动态力学分析得到了玻璃化转变温度（Tg）和网络的不均匀性。TU的添加导致机械性能的增加（除了Tg和FS）。TU改性组的断裂韧性范围为1.6-1.94 MPa.m1/2，与对照组（1.21±0.1 MPa.m1/2）相比增加了33-61%。与对照相比，韧性增加了两倍：从0.91 MPa增加到1.70-1.95 MPa。TU改良组的弯曲模量在统计学上更高。如所预期的，由于赋予网络更大的柔性（这也解释了韧性和断裂韧性的增加），所有TU基团的Tg都降低。较窄的tan-δ峰表明TU改性的材料具有更均匀的网络，尽管仅对TMP_AL有显著差异。所有组的VS相似，只有一个例外，即VS下降（PETMP-循环）。最后，与对照组（15.56±1.4 MPa）相比，TU改良组（6.7±1.3至11.9±1.0 MPa）的PS降低了23-57%。添加硫代氨基甲酸酯低聚物能够降低聚合应力高达57%，同时增加断裂韧性高达61%。
Thio-urethane oligomers (TUs) have been shown to favorably modify methacrylate networks to reduce stress and significantly increase fracture toughness. Since those are very desirable features in dental applications, the objective of this work was to characterize restorative composites formulated with the addition of TUs. TUs were synthesized by combining thiols - pentaerythritol tetra-3-mercaptopropionate (PETMP) or trimethylol-tris-3-mercaptopropionate (TMP) - with isocyanates - 1,6-Hexanediol-diissocyante (HDDI) (aliphatic) or 1,3-bis(1-isocyanato-1-methylethyl)benzene (BDI) (aromatic) or dicyclohexylmethane 4,4′-Diisocyanate (HMDI) (cyclic), at 1:2 isocyanate:thiol, leaving pendant thiols. 20 wt% TU were added to BisGMA-TEGDMA (70–30%). To this organic matrix, 70 wt% silanated inorganic fillers were added. Near-IR was used to follow methacrylate conversion and rate of polymerization (Rpmax). Mechanical properties were evaluated in three-point bending (ISO 4049) for flexural strength/modulus (FS/FM) and toughness (T), and notched specimens (ASTM Standard E399-90) for fracture toughness (KIC). Polymerization stress (PS) was measured on the Bioman. Volumetric shrinkage (VS) was measured with the bonded disk technique. Glass transition temperature (Tg) and heterogeneity of network were obtained with dynamic mechanical analysis. The addition of TUs led to an increase in mechanical properties (except for Tg and FS). Fracture toughness ranged from 1.6–1.94 MPa.m1/2 for TU-modified groups, an increase of 33–61% in relation to the control (1.21±0.1 MPa.m1/2). Toughness showed a two-fold increase in relation to the control: from 0.91 MPa to values ranging from 1.70–1.95 MPa. Flexural modulus was statistically higher for the TU-modified groups. The Tg, as expected, decreased for all TU groups due to the greater flexibility imparted to the network (which also explains the increase in toughness and fracture toughness). Narrower tan-delta peaks suggest more homogeneous networks for the TU-modified materials, though differences were marked only for TMP_AL. Degree of conversion was not affected by the addition of TUs. VS was similar for all groups, with one exception where VS dropped (PETMP-cyclic). Finally, PS showed a reduction of 23–57% for TU-modified groups (6.7±1.3 to 11.9±1.0 MPa) in relation to the control (15.56±1.4 MPa). The addition of thio-urethane oligomers was able to reduce polymerization stress by up to 57% while increasing fracture toughness by up to 61%.
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影响因子：
5
作者：
Bacchi, Atais;Pfeifer, Carmem S.
通讯作者：
Pfeifer, Carmem S.
影响因子：
5.2
作者：
Sun, C. J.;Wu, W.;Debnath, S.
通讯作者：
Debnath, S.
影响因子：
5
作者：
Watts, David C.;Satterthwaite, Julian D.
通讯作者：
Satterthwaite, Julian D.
DOI：
10.1016/j.dental.2015.02.008
发表时间：
2015-05
期刊：
Dental materials : official publication of the Academy of Dental Materials
影响因子：
--
作者：
Bacchi A;Consani RL;Martim GC;Pfeifer CS
通讯作者：
Pfeifer CS
影响因子：
4.3
作者：
Riener, CK;Kada, G;Gruber, HJ
通讯作者：
Gruber, HJ