Statement Of Problem: Flowable composite is used in a variety of clinical applications; however, the capacity of these materials to resist crack propagation is not well understood.
Purpose: The purpose of this investigation was to compare the resistance to crack propagation of 9 flowable composites as measured by the fracture toughness.
Material And Methods: The composites studied include AeliteFlo, Crystal Essence, Flow-it, FloRestore, Permaflo, Revolution, Tetric Flow, VersaFlo, and Wave. Ten specimens of each composite were formed with a brass mold with a 3-mm preformed notch. The final dimensions of each specimen were 2 x 4.2 x 20 mm. All specimens were light-polymerized to manufacturer specifications and stored in air for 24 hours. The fracture toughness value, K(IC) (MNm(-3/2)), for each specimen was measured by use of a 3-point bending mode and a single-edge notched beam at a crosshead speed of 0.125 mm/min until fracture. The data were analyzed statistically by use of 1-way analysis of variance, t tests (P<.05), and regression analysis.
Results: The flowable composites tested showed a spectrum of fracture toughness values ranging from 1.15 +/- 0.10 MNm(-3/2) for Wave to 1.65 +/- 0.13 MNm(-3/2) for Permaflo (significantly different, P<.05). The remaining materials formed 1 group with intermediate K(IC) values not different from each other (P>.05) but significantly different from Wave and Permaflo. Comparisons of fracture toughness to the filler content by volume of each composite revealed no correlation.
Conclusion: This in vitro study concluded that there was no significant difference among 7 of the 9 composites tested in their resistance to fracture. Permaflo showed the greatest resistance to crack propagation. There was no correlation between the filler content by volume and the fracture toughness of these flowable composites.
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http://dx.doi.org/10.1067/mpr.2003.33 | DOI Listing |
Heliyon
January 2025
Centre for functional and surface functionalized glass, Alexander Dubček University of Trenčín, Študentská 2, Trenčín, Slovakia.
The impact of grinding on particle size, thermal behaviour, and sintering ability of yttrium aluminate glass microspheres with eutectic composition (76.8 mol % AlO and 23.2 mol % YO) was studied.
View Article and Find Full Text PDFLangmuir
January 2025
State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an 710072, China.
Palm leaf manuscripts, crafted from specially treated palm leaves, are invaluable historical documents. However, they degrade and tend to become brittle over time. To date, plant essential oils and glycerin are the used materials to improve the flexibility of palm leaf manuscripts, but the effective duration of these materials is short due to their volatility.
View Article and Find Full Text PDFActa Biomater
January 2025
The Key Laboratory of Bionic Engineering, Ministry of Education, Jilin University, Changchun 130025, China.
Natural materials are valued for their lightweight properties, high strength, impact resistance, and fracture toughness, often outperforming human-made materials. This paper reviews recent research on biomimetic composites, focusing on how composition, microstructure, and interfacial characteristics affect mechanical properties like strength, stiffness, and toughness. It explores biological structures such as mollusk shells, bones, and insect exoskeletons that inspire lightweight designs, including honeycomb structures for weight reduction and impact resistance.
View Article and Find Full Text PDFMaterials (Basel)
January 2025
Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650031, China.
Fracture toughness is an important index related to the service safety of marine risers, and weld is an essential component of the steel catenary risers. In this paper, microscopic structure characterization methods such as scanning electron microscopy (SEM) and electron back scatter diffraction (EBSD), as well as mechanical experiments like crack tip opening displacement (CTOD) and nanoindentation, were employed to conduct a detailed study on the influence of the microstructure characteristics of multi-wire submerged arc welded seams of steel catenary riser pipes on CTOD fracture toughness. The influence mechanisms of each microstructure characteristic on fracture toughness were clarified.
View Article and Find Full Text PDFMaterials (Basel)
January 2025
School of Civil Engineering, Southwest Jiaotong University, Chengdu 610031, China.
Defects can be introduced into shotcrete materials after a few freeze-thaw cycles, which has a significant influence on the fracture performance of shotcrete. In this study, a series of shotcrete specimens with varying sizes, geometries, and initial crack lengths were prepared to investigate the fracture properties of notched shotcrete under freeze-thaw conditions. Considering the effects of specimen boundaries and material microstructure, a linear closed-form solution was proposed to determine the fracture toughness of frost-damaged shotcrete.
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