title: Hardness and fracture toughness of four commercial visible light-cured composite resin veneering materials.
abstract: Four commercial visible light (VL)-cured composite resin veneering materials with a dentine shade were examined for their Knoop hardness and fracture toughness. Composite specimens were classified into three groups. The first group was cured by VL only, the second group was cured by VL and post-cured by VL and the third group was cured by VL and post-cured by heat. It became evident that one composite containing four-functional urethane monomer had both hardness and fracture toughness greater than those of the other three composites containing two-functional urethane monomer. The filler content (vol%) in the composite tended to be linearly proportional to both hardness and fracture toughness. Post-curing by VL and heat were proven to effectively increase both hardness and fracture toughness of once light-cured composites. These results suggest that the clinical performance (e.g. wear resistance and colour stability) of VL-cured composite resin veneering materials might be improved with the aid of post-curing.
authors.affiliation: Department of Removable Prosthodontics, Hiroshima University School of Dentistry, Minami-ku, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Yamaga
authors.forename: Y
authors.initials: Y
authors.lastname: Sato
authors.forename: Y
authors.initials: Y
authors.lastname: Akagawa
authors.forename: M
authors.initials: M
authors.lastname: Taira
authors.forename: K
authors.initials: K
authors.lastname: Wakasa
authors.forename: M
authors.initials: M
authors.lastname: Yamaki
mesh_terms: D003188:Composite Resins / Q000737:chemistry*; D003801:Dental Veneers; D006244:Hardness; D006358:Hot Temperature; D008027:Light; D016014:Linear Models; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D011140:Polyurethanes / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry; D012821:Silanes / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013674:Technology, Dental / Q000379:methods
chemical_list: D003188:Composite Resins; D008689:Methacrylates; D011140:Polyurethanes; D019279:Resin Cements; D012821:Silanes; C083619:thermoresin LC; C091839:urethanetrimethacrylate; C029824:urethane dimethacrylate luting resin; C083618:new metacolor; C083620:cesead; C057365:Dentacolor