title: Effect of light-curing method and indirect veneering materials on the Knoop hardness of a resin cement.
abstract: This study evaluated the Knoop hardness of a dual-cured resin cement (Rely-X ARC) activated solely by chemical reaction (control group) or by chemical / physical mode, light-cured through a 1.5 mm thick ceramic (HeraCeram) or composite (Artglass) disc. Light curing was carried out using conventional halogen light (XL2500) for 40 s (QTH); light emitting diodes (Ultrablue Is) for 40 s (LED); and Xenon plasma arc (Apollo 95E) for 3 s (PAC). Bovine incisors had their buccal face flattened and hybridized. On this surface a rubber mold (5 mm in diameter and 1 mm in height) was bulk filled with the resin cement. A polyester strip was seated for direct light curing or through the discs of veneering materials. After dry storage in the dark (24 h 37 degrees C), the samples (n = 5) were sectioned for hardness (KHN) measurements, taken in a microhardness tester (50 gF load 15 s). The data were statistically analyzed by ANOVA and Tukey's test (alpha = 0.05). The cement presented higher Knoop hardness values with Artglass for QTH and LED, compared to HeraCeram. The control group and the PAC/Artglass group showed lower hardness values compared to the groups light-cured with QTH and LED. PAC/HeraCeram resulted in the worst combination for cement hardness values.
authors.affiliation: Department of Restorative Dentistry - Piracicaba Dental School, University of Campinas (UNICAMP), Campinas, SP, Brazil.
authors.forename: Nelson Tetsu
authors.initials: NT
authors.lastname: Iriyama
authors.forename: Rubens Nisie
authors.initials: RN
authors.lastname: Tango
authors.forename: Izabella Paola
authors.initials: IP
authors.lastname: Manetta
authors.forename: Mário Alexandre Coelho
authors.initials: MA
authors.lastname: Sinhoreti
authors.forename: Lourenço Correr
authors.initials: LC
authors.lastname: Sobrinho
authors.forename: Guilherme de Siqueira Ferreira Anzaloni
authors.initials: Gde S
authors.lastname: Saavedra
mesh_terms: D000818:Animals; D002417:Cattle; D055117:Curing Lights, Dental / Q000592:standards; D003801:Dental Veneers; D006245:Hardness Tests; D055115:Light-Curing of Dental Adhesives / Q000379:methods*; D008422:Materials Testing; D019279:Resin Cements / Q000737:chemistry / Q000528:radiation effects*; D055116:Self-Curing of Dental Resins; D013499:Surface Properties; D013997:Time Factors
chemical_list: C095997:DCR cement; C528569:Rely-X; D019279:Resin Cements