title: Fracture toughness of aged dental composites in combined mode I and mode II loading.
abstract: Resin-based laboratory dental composites for prosthetic restorations have been developed in the past years as a cost-effective alternative to conventional porcelain-fused-to-metal or full ceramic restorations. The fracture toughness at different stress states (K(Ic), K(IIc), and mixed-modes K(I), K(II) ) was assessed for three laboratory dental composite resins used for prosthetic restorations that were aged up to 12 months in a food simulating fluid (10% ethanol) at 37 degrees C. The materials were mainly di- methacrylate based resins reinforced with submicron glass filler particles. The Brazilian disk test was used on precracked chevron-notched specimens, and different stress states were obtained by angulating the precracked chevron notch relative to the diametral compressive loading direction. The stress intensity factors were calculated using Atkinson et al.'s relation. For all three materials, mode I fracture toughness values ranged between 0.48-0.64 MPa. m(0.5) and mode II values ranged between 0.93-1.2 MPa. m(0.5). Overall, aging time and storage media had little effect on toughness. Considering the inherently low toughness of these restorative materials, their use should be limited to low stress masticatory areas.
authors.affiliation: Department of Prosthodontics, School of Dentistry, University of Geneva, Switzerland. susanne.scherrer&medecine.unige.ch
authors.forename: S S
authors.initials: SS
authors.lastname: Scherrer
authors.forename: J
authors.initials: J
authors.lastname: Botsis
authors.forename: M
authors.initials: M
authors.lastname: Studer
authors.forename: M
authors.initials: M
authors.lastname: Pini
authors.forename: H W
authors.initials: HW
authors.lastname: Wiskott
authors.forename: U C
authors.initials: UC
authors.lastname: Belser
mesh_terms: D000537:Aluminum Oxide; D001464:Barium; D003188:Composite Resins; D005899:Glass Ionomer Cements; D006801:Humans; D008689:Methacrylates; D012823:Silicate Cement; D012822:Silicon Dioxide; D013499:Surface Properties
chemical_list: D003188:Composite Resins; D005899:Glass Ionomer Cements; D008689:Methacrylates; C111282:dental polyglass; D012823:Silicate Cement; D001464:Barium; D012822:Silicon Dioxide; D000537:Aluminum Oxide