Omran Tarek A, Garoushi Sufyan, Lassila Lippo V, Vallittu Pekka K
Finnish Doctoral Program in Oral Sciences (FINDOS), Turku, Finland.
Department of Biomaterials Science, Institute of Dentistry, Faculty of Medicine, University of Turku, Turku, Finland.
Eur J Oral Sci. 2019 Jun;127(3):276-284. doi: 10.1111/eos.12617. Epub 2019 Apr 19.
This study aimed to evaluate the effect of different interface designs on the load-bearing capacity of bilayered composite structures (BLS). Cylindrical specimens of BLS were prepared from base composite of 3.5 mm thickness and surface composite of 1.5 mm thickness (n = 80). Two different base composites - flowable bulk-fill (FBF) [smart dentin replacement (SDR)] and short fiber-reinforced (FRC) (everX Posterior) - were evaluated, and conventional composite (G-aenial Posterior) was used as the surface layer. Four different interface designs were used: (i) pyramidal; (ii) mesh; (iii) linear grooves; and (iv) flat surface (control). Three-dimensional printed molds were fabricated to standardize the interface design between the surface and the base composites. The specimens were then statically loaded with a steel ball until fracture using a universal testing machine. Fracture types were classified into catastrophic, complete, and partial bulk. ANOVA revealed that both the material and the interface design had a statistically significant effect on the load-bearing capacity. Flowable bulk-fill showed lower mean load-bearing capacity than FRC in all the interface designs tested, except for the flat surface design. Fracture analysis showed that FRC demonstrated up to 100% partial bulk fractures with the pyramid interface design, but no incidence of catastrophic bulk fracture. By contrast, FBF demonstrated up to 84.6% and 40% catastrophic bulk fractures with the flat interface design but no incidence of partial bulk fracture. Consequently, the interface designs studied enhanced the fracture behavior of BLS.
本研究旨在评估不同界面设计对双层复合结构（BLS）承载能力的影响。BLS的圆柱形试件由厚度为3.5毫米的基底复合材料和厚度为1.5毫米的表面复合材料制成（n = 80）。评估了两种不同的基底复合材料——可流动块状填料（FBF）[智能牙本质替代材料（SDR）]和短纤维增强（FRC）（everX Posterior），并使用传统复合材料（G-aenial Posterior）作为表层。采用了四种不同的界面设计：（i）金字塔形；（ii）网格形；（iii）线性凹槽形；以及（iv）平面（对照）。制作了三维打印模具，以规范表面和基底复合材料之间的界面设计。然后使用万能试验机用钢球对试件进行静态加载直至断裂。将断裂类型分为灾难性、完全性和部分块状。方差分析显示，材料和界面设计对承载能力均有统计学上的显著影响。在所有测试的界面设计中，除平面设计外，可流动块状填料的平均承载能力均低于FRC。断裂分析表明，采用金字塔形界面设计时，FRC出现高达100%的部分块状断裂，但无灾难性块状断裂发生。相比之下，采用平面界面设计时，FBF出现高达84.6%和40%的灾难性块状断裂，但无部分块状断裂发生。因此，所研究的界面设计改善了BLS的断裂行为。
