title: Effect of surface pretreatments on the microtensile bond strength of lithium-disilicate ceramic repaired with composite resin.
abstract: The aim of this study was to evaluate the influence of ceramic surface treatments and silane drying temperature on the microtensile bond strength (µTBS) of a resin composite to a lithium disilicate ceramic. Twenty blocks (7x7x5 mm) of lithium disilicate-based hot-pressed ceramic were fabricated and randomly divided into 4 groups: G1: acid etching with 9.5% hydrofluoric acid for 20 s and drying silane with room-temperature air; G2: acid etching with 9.5% hydrofluoric acid for 20 s and drying silane with 45 ± 5 °C warm air; G3: airborne-particle abrasion with 50 µm aluminum oxide particles and drying silane with 45 ± 5 °C warm air; G4: airborne-particle abrasion with 50 µm aluminum oxide particles and drying silane with air at room-temperature. After treatments, an adhesive system (Single Bond 2) was applied, light-cured and direct restorations were built up with a resin composite (Filtek Z250). Each specimen was stored in distilled water at 37 °C for 24 h and cut into ceramic-composite beams with 1 mm2 of cross-sectional area for µTBS testing. Statistical analysis was performed with one-way ANOVA and Student-Newman-Keuls test (α=0.05). µTBS means (S.D.) in MPa were: G1: 32.14 (7.98), G2: 35.00 (7.77) and G3: 18.36 (6.17). All specimens of G4 failed during the cutting. G1 and G2 presented significantly higher µTBS than G3 (p<0.05). There was no statistically significant difference between G1 and G2 (p>0.05). As far as the bond strength is concerned, surface pretreatment of lithium-disilicate ceramic with hydrofluoric acid and silane application can be used as an alternative to repair ceramic restorations with composite resin, while surface pretreatment with sandblasting should be avoided.
authors.affiliation: UNIFOR - University of Fortaleza, FortalezaCE, Brazil.
authors.forename: Regina Cláudia Ramos
authors.initials: RC
authors.lastname: Colares
authors.forename: Jiovanne Rabelo
authors.initials: JR
authors.lastname: Neri
authors.forename: André Mattos Brito de
authors.initials: AM
authors.lastname: Souza
authors.forename: Karina Matthes de Freitas
authors.initials: KM
authors.lastname: Pontes
authors.forename: Juliano Sartori
authors.initials: JS
authors.lastname: Mendonça
authors.forename: Sérgio Lima
authors.initials: SL
authors.lastname: Santiago
mesh_terms: D002516:Ceramics; D003764:Dental Materials; D003776:Dental Porcelain / Q000737:chemistry*; D013499:Surface Properties; D013718:Tensile Strength
chemical_list: D003764:Dental Materials; C493120:lithia disilicate; D003776:Dental Porcelain