Shouha Paul, Swain Michael, Ellakwa Ayman
Biomaterials Science, Discipline of Biomaterials, Faculty of Dentistry, The University of Sydney, Sydney Dental Hospital, 2 Chalmers St., Surry Hills, Sydney, NSW 2010, Australia.
Biomaterials Science, Discipline of Biomaterials, Faculty of Dentistry, The University of Sydney, Sydney Dental Hospital, 2 Chalmers St., Surry Hills, Sydney, NSW 2010, Australia.
Dent Mater. 2014 Nov;30(11):1234-44. doi: 10.1016/j.dental.2014.08.363. Epub 2014 Sep 16.
To evaluate the efficacy on flexural properties of flowable dental resin composite reinforced with short glass fiber of different aspect ratios (ARs) and volume percent loadings. It is hypothesized that with the addition of randomly oriented fibers it is possible to significantly improve flexural strength and modulus while maintaining flowability.
Ten groups of samples with varying glass fiber volume loads (0, 5%, 10%, 20%, 40% and 60%) and three different ARs (5.2, 68 and 640) were tested in three point bending to fracture according to ISO 4049. A flowable resin composite was used as the control and also as the filled resin composite that was subsequently reinforced with fibers. Load deflection results were used to calculate flexural strength and flexural modulus. SEM images were used to determine the mode(s) of failure, to describe surface features of reinforcement and were correlated with force displacement graphs. All results were statistically analysed using ANOVA followed by post hoc Tukey's test. Level of significance was set at 0.05.
When compared to the "sculptable" control (68.6 vol% filler loaded) results for flexural strength varied from a mean reduction of 42% (p>0.05) for the low AR group to an increase of 77% (p<0.001) for the high AR samples. Flexural modulus results varied from a low of 6.6 [0.67] GPa for the non reinforced spatulated control to 20.3 [1.31] GPa (p<0.001) for the 60% loaded low AR group. The low fiber loaded mid AR group was still flowable with 49% total loading (5% fiber/44% filler) but gave strength values (181.2 [33.5] MPa) 30% higher than the "sculptable" control (p>0.05) and comparable modulus.
This study shows that short and very short glass fibers can significantly reinforce flowable dental composite. The fiber's aspect ratio was shown to be more important than volume loading for flexural strength. It appears possible to produce a light cured short glass fiber reinforced flowable material with superior flexural properties compared to conventional universal composites.
评估不同长径比（AR）和体积百分比含量的短玻璃纤维增强可流动牙科树脂复合材料的弯曲性能。假设添加随机取向的纤维可以在保持流动性的同时显著提高弯曲强度和模量。
根据ISO 4049标准，对十组具有不同玻璃纤维体积含量（0%、5%、10%、20%、40%和60%）以及三种不同长径比（5.2、68和640）的样品进行三点弯曲至断裂测试。使用一种可流动树脂复合材料作为对照，同时也作为随后用纤维增强的填充树脂复合材料。载荷-挠度结果用于计算弯曲强度和弯曲模量。扫描电子显微镜（SEM）图像用于确定失效模式，描述增强材料的表面特征，并与力-位移图相关联。所有结果均使用方差分析（ANOVA）进行统计分析，随后进行事后Tukey检验。显著性水平设定为0.05。
与“可雕刻”对照（填充量为68.6体积%）相比，弯曲强度结果变化范围为：低长径比组平均降低42%（p>0.05），高长径比样品组增加77%（p<0.001）。弯曲模量结果变化范围为：未增强的调拌对照为6.6[0.67]GPa，60%含量的低长径比组为20.3[1.31]GPa（p<0.001）。低纤维含量的中等长径比组在总含量为49%（5%纤维/44%填料）时仍具有流动性，但其强度值（181.2[33.5]MPa）比“可雕刻”对照高30%（p>0.05），模量相当。
本研究表明，短和极短的玻璃纤维可以显著增强可流动牙科复合材料。对于弯曲强度而言，纤维的长径比显示出比体积含量更为重要。与传统通用复合材料相比，似乎有可能生产出具有优异弯曲性能的光固化短玻璃纤维增强可流动材料。
