title: Discontinuous fiber-reinforced composites above critical length.
abstract: Micromechanical physics of critical fiber length, describing a minimum filament distance for resin impregnation and stress transfer, has not yet been applied in dental science. As a test of the hypothesis that 9-micron-diameter, 3-mm-long quartz fibers would increase mechanical strength over particulate-filled composites, photocure-resin-pre-impregnated discontinuous reinforcement was incorporated at 35 wt% into 3M Corporation Z100, Kerr Corporation HerculiteXRV, and an experimental photocure paste with increased radiopaque particulate. Fully articulated four-point bend testing per ASTM C 1161-94 for advanced ceramics and Izod impact testing according to a modified unnotched ASTM D 256-00 specification were then performed. All photocure-fiber-reinforced composites demonstrated significant improvements over particulate-filled compounds (p < 0.001) for flexural strength, modulus, work of fracture, strain at maximum load, and Izod toughness, with one exception for the moduli of Z100 and the experimental reinforced paste. The results indicate that inclusion of pre-impregnated fibers above the critical aspect ratio yields major advancements regarding the mechanical properties tested.
authors.affiliation: University of Alabama at Birmingham, School of Engineering, Department of Biomedical Engineering, Hoehn Building, Room 330, Birmingham, AL 35294, USA. rpetersen@cs1.dental.uab.edu
authors.forename: R C
authors.initials: RC
authors.lastname: Petersen
mesh_terms: D000704:Analysis of Variance; D017438:Bisphenol A-Glycidyl Methacrylate; D003188:Composite Resins; D003720:Densitometry; D003799:Dental Stress Analysis; D004548:Elasticity; D005898:Glass; D008422:Materials Testing; D018625:Microscopy, Atomic Force; D055585:Physical Phenomena; D010825:Physics; D018583:Pliability; D011092:Polyethylene Glycols; D011109:Polymethacrylic Acids; D011791:Quartz; D019279:Resin Cements; D012822:Silicon Dioxide; D015040:Zirconium
chemical_list: D003188:Composite Resins; D011109:Polymethacrylic Acids; D019279:Resin Cements; C083568:Z100 composite resin; C009753:fiberglass; C065770:Herculite XR; D011791:Quartz; C020946:triethylene glycol dimethacrylate; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate; D012822:Silicon Dioxide; D015040:Zirconium