title: Bond durability in erbium:yttrium-aluminum-garnet laser-irradiated enamel.
abstract: This study sought to evaluate the influence of thermocycling and water storage on the microtensile bond strength of composite resin bonded to erbium:yttrium-aluminum-garnet (Er:YAG)-irradiated and bur-prepared enamel. Eighty bovine incisors were selected and sectioned. Specimens were ground to produce a flat enamel surface. Samples were randomly assigned according to cavity preparation device: (I) Er:YAG laser and (II) high-speed turbine, and were subsequently restored with composite resin. They were subdivided according to the duration of water storage (WS)/number of thermocycles (TCs): 24 h WS/no TCs; 7 days WS/500 TCs; 1 month WS/2,000 TCs; 6 months WS/12,000 TCs. The teeth were sectioned into 1.0 mm(2)-thick slabs and subjected to tensile stress in a universal testing machine. Data were submitted to two-way analysis of variance (ANOVA) and Tukey's test at a 0.05 significance level. The different periods of water storage and thermocycling did not influence the microtensile bond strength (microTBS) values in the Er:YAG laser-prepared groups. In bur-prepared enamel, the group submitted to 12,000 TCs/6 months' WS (IID) showed a significant decrease in bond strength values when compared to the group stored in water for 24 h and not submitted to thermocycling (IIA), but values were statistically similar to those obtained in all Er:YAG laser groups and in the bur- prepared groups degraded with 500 TCs/1 week WS (IIB) or 2,000 TCs/1 month WS (IIC). It may be concluded that adhesion of an etch-and-rinse adhesive to Er:YAG laser-irradiated enamel was not affected by the methods used to simulate degradation of the adhesive interface and was similar to adhesion in the bur-prepared groups in all periods of water storage and thermocycling.
authors.affiliation: Department of Operative Dentistry, Ribeirão Preto School of Dentistry, University of São Paulo (USP), Av. do Café, S/N, Monte Alegre, Ribeirão Preto, 14040-904 São Paulo, Brazi. flbamaral@gmail.com
authors.forename: F L B
authors.initials: FL
authors.lastname: Amaral
authors.forename: V
authors.initials: V
authors.lastname: Colucci
authors.forename: A E
authors.initials: AE
authors.lastname: Souza-Gabriel
authors.forename: M A
authors.initials: MA
authors.lastname: Chinelatti
authors.forename: R G
authors.initials: RG
authors.lastname: Palma-Dibb
authors.forename: S A M
authors.initials: SA
authors.lastname: Corona
mesh_terms: D000818:Animals; D002417:Cattle; D001840:Dental Bonding / Q000379:methods*; D003737:Dental Cavity Preparation / Q000379:methods; D003743:Dental Enamel / Q000528:radiation effects* / Q000648:ultrastructure; D066298:In Vitro Techniques; D053844:Lasers, Solid-State / Q000627:therapeutic use*; D008855:Microscopy, Electron, Scanning; D013718:Tensile Strength