Objective

The aim was to evaluate the effect of short glass-fiber/filler particles proportion on fracture toughness (FT) and flexural strength (FS) of an experimental flowable fiber-reinforced composite (Exp-SFRC) with two methacrylate resin formulations. In addition, we wanted to investigate how the fracture-behavior of composite restorations affected by FT values of SFRC-substructure.

Methods

Exp-SFRC was prepared by mixing 50 wt% of dimethacrylate based resin matrix (bisGMA or UDMA based) to 50 wt% of various weight fractions of glass-fiber/particulate filler (0:50, 10:40, 20:30, 30:20, 40:10, 50:0 wt%, respectively). FT and FS were determined for each experimental material following standards. Specimens (n = 8) were dry stored (37 °C for 2 days) before they were tested. Four groups of posterior composite crowns (n = 6) composed of different Exp-SFRCs as substructure and surface layer of commercial particulate filler composite were fabricated. Crowns were statically loaded until fracture. Failure modes were visually examined. The results were statistically analysed using ANOVA followed by post hoc Tukey’s test.

Results

ANOVA revealed that ratio of glass-fiber/particulate filler had significant effect (p < 0.05) on tested mechanical properties of the Exp-SFRC with both monomer systems. Exp-SFRC (50 wt%) had significantly higher FT (2.6 MPam^1/2) and FS (175.5 MPa) (p < 0.05) compared to non-reinforced material (1.3 MPam^1/2, 123 MPa). Failure mode analysis of crown restorations revealed that FT value of the substructure directly influenced the failure mode.

Significance

This study shows that short glass-fibers can significantly reinforce flowable composite resin and the FT value of SFRC-substructure has prior importance, as it influences the crack arresting mechanism.

中文翻译：

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流动性纤维增强复合材料修复体的力学性能和断裂行为

客观的

目的是评估短玻璃纤维/填料颗粒比例对具有两种甲基丙烯酸酯树脂配方的实验性可流动纤维增强复合材料（Exp-SFRC）的断裂韧性（FT）和抗弯强度（FS）的影响。此外，我们想研究复合修复体的断裂行为如何受SFRC子结构的FT值影响。

方法

通过将50 wt％的基于二甲基丙烯酸酯的树脂基体（基于bisGMA或UDMA）与50 wt％的各种重量分数的玻璃纤维/颗粒填料（0：50、10：40、20：30、30）混合来制备Exp-SFRC分别为：20、40：10、50：0 wt％）。遵循标准为每种实验材料确定FT和FS。样品（n = 8）在测试前应进行干燥保存（37°C 2天）。制作了四组由不同Exp-SFRC组成的后复合材料牙冠（n = 6），作为商业颗粒填料复合材料的子结构和表面层。牙冠被静态加载直到断裂。目视检查失效模式。使用ANOVA和事后Tukey检验对结果进行统计分析。

结果

方差分析表明，玻璃纤维/颗粒填料的比例对两种单体体系的Exp-SFRC的力学性能均具有显着影响（p <0.05）。与非增强材料（1.3 MPam ^1/ 2，123 MPa）相比，Exp-SFRC（50 wt％）具有显着更高的FT（2.6 MPam ^1/2）和FS（175.5 MPa）（p <0.05 ）。牙冠修复体的破坏模式分析表明，子结构的FT值直接影响破坏模式。

意义

这项研究表明，短玻璃纤维可以显着增强可流动的复合树脂，而SFRC-亚结构的FT值具有先验重要性，因为它影响了裂纹的阻止机理。