title: Effect of immediate and delayed light activation on the mechanical properties and degree of conversion in dual-cured resin cements.
abstract: We evaluated the effect of activation mode (immediate or delayed light activation vs. no light activation) on diametral tensile strength (DTS), elastic modulus, ultimate tensile strength (UTS), and degree of conversion (DC) in dual-cured resin cements. Three resin cements were evaluated: Enforce, RelyX ARC, and Panavia F. The mixed cements were inserted into circular molds for the DTS test and into dumbbell-shaped molds for the UTS test. Inside the molds, the cements were light-activated either immediately or after 5 min (delayed light activation). If no light activation was performed, the materials were protected from light exposure (control). The DTS and UTS tests were performed until fracture. The elastic modulus was calculated using data from the DTS test, and DC was evaluated 24 h after manipulation using near-infrared spectroscopy. Data for each variable were individually analyzed by two-way ANOVA and the post-hoc Tukey test (α = 0.05). Regarding DTS, activation mode influenced only Panavia Fspecimens, which had the lowest DTS values in the absence of light activation. Activation mode did not influence the elastic modulus or UTS of any resin cement evaluated. Immediate light activation yielded higher DC values as compared with the absence of light activation.
authors.affiliation: Department of Dentistry, Federal University of Sergipe, Aracaju, SE, Brazil. andrelfsilva@hotmail.com
authors.forename: André L
authors.initials: AL
authors.lastname: Faria-e-Silva
authors.forename: Evandro
authors.initials: E
authors.lastname: Piva
authors.forename: Giana S
authors.initials: GS
authors.lastname: Lima
authors.forename: Letícia C
authors.initials: LC
authors.lastname: Boaro
authors.forename: Roberto R
authors.initials: RR
authors.lastname: Braga
authors.forename: Luis R M
authors.initials: LR
authors.lastname: Martins
mesh_terms: D000704:Analysis of Variance; D017438:Bisphenol A-Glycidyl Methacrylate / Q000528:radiation effects; D003799:Dental Stress Analysis; D055119:Elastic Modulus / Q000528:radiation effects; D008027:Light; D008422:Materials Testing; D011092:Polyethylene Glycols / Q000528:radiation effects; D058105:Polymerization; D011109:Polymethacrylic Acids / Q000528:radiation effects; D019279:Resin Cements / Q000737:chemistry* / Q000528:radiation effects*; D055116:Self-Curing of Dental Resins; D018709:Statistics, Nonparametric; D013314:Stress, Mechanical; D013718:Tensile Strength / Q000528:radiation effects
chemical_list: C103503:EnForce-Sure Cure; C438843:Panavia-Fluoro; D011109:Polymethacrylic Acids; C462240:RelyX ARC; D019279:Resin Cements; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate