Lassila Lippo, Säilynoja Eija, Prinssi Roosa, Vallittu Pekka K, Garoushi Sufyan
Department of Biomaterials Science and Turku Clinical Biomaterial Center - TCBC, Institute of Dentistry, University of Turku, Turku, Finland.
Research Development and Production Department, Stick Tech Ltd - Member of GC Group, Turku, Finland.
Biomater Investig Dent. 2020 Jun 2;7(1):80-85. doi: 10.1080/26415275.2020.1770094. eCollection 2020.
By combining the increased toughness of a resin composite reinforced with discontinuous fibers and the surface wear resistance of a particulate filler composite (PFC), a bilayered composite technique was recently introduced. This study aimed to evaluate the effect of the thickness of the overlaying PFC placed over a fiber-reinforced composite (FRC) core, on the fracture-behavior of direct crown restorations. Six groups of posterior crown restorations ( = 8/group) were fabricated having a discontinuous FRC-core (everX Flow) and a layer of surface PFC (Essentia U) with various thicknesses (0.5, 1.0, 1.5, 2.0 mm), with the remaining thickness of the bilayered being 6 mm. Control groups were only made of PFC or FRC materials. Restorations were statically loaded until fracture. Failure-modes were visually examined. Data were analyzed using ANOVA ( = .05) and regression analysis. The regression analysis showed that by decreasing the thickness of PFC layer, the load bearing capacity of restorations increased linearly (R=0.7909). ANOVA revealed that crown restorations made only from everX Flow composite had significantly higher load-bearing capacities (3990 ± 331 N) ( < .05) among all the groups tested. With regard to the failure-mode analysis, crowns that had a FRC core material of everX Flow revealed delamination of the PFC surface composite from the core. Crowns which were made only of PFC i.e. with no fiber reinforcement, showed a crushing-like fracture pattern. Restorations combining a thick FRC-core and a thin surface layer of PFC (0.5-1 mm), displayed promising performance related to fracture-behavior and load-bearing capacity.
通过结合用不连续纤维增强的树脂复合材料的更高韧性和颗粒填料复合材料（PFC）的表面耐磨性，最近引入了一种双层复合材料技术。本研究旨在评估置于纤维增强复合材料（FRC）核上的覆盖PFC的厚度对直接冠修复体断裂行为的影响。制作了六组后牙冠修复体（每组n = 8），其具有不连续的FRC核（everX Flow）和一层不同厚度（0.5、1.0、1.5、2.0 mm）的表面PFC（Essentia U），双层结构的剩余厚度为6 mm。对照组仅由PFC或FRC材料制成。对修复体进行静态加载直至断裂。目视检查失败模式。使用方差分析（α = 0.05）和回归分析对数据进行分析。回归分析表明，通过减小PFC层的厚度，修复体的承载能力呈线性增加（R = 0.7909）。方差分析显示，在所有测试组中，仅由everX Flow复合材料制成的冠修复体具有显著更高的承载能力（3990 ± 331 N）（P < 0.05）。关于失败模式分析，具有everX Flow的FRC核心材料的冠显示PFC表面复合材料与核心分层。仅由PFC制成即没有纤维增强的冠显示出类似挤压的断裂模式。结合厚FRC核和薄PFC表面层（0.5 - 1 mm）的修复体在断裂行为和承载能力方面表现出良好的性能。
