title: Evaluation of bond strength and thickness of adhesive layer according to the techniques of applying adhesives in composite resin restorations.
abstract: Adhesive restorations have increasingly been used in dentistry, and the adhesive system application technique may determine the success of the restorative procedure. The aim of this study was to evaluate the influence of the application technique of two adhesive systems (Clearfil SE Bond and Adper Scotchbond MultiPurpose) on the bond strength and adhesive layer of composite resin restorations. Eight human third molars were selected and prepared with Class I occlusal cavities. The teeth were restored with composite using various application techniques for both adhesives, according to the following groups (n = 10): group 1 (control), systems were applied and adhesive was immediately light activated for 20 seconds without removing excesses; group 2, excess adhesive was removed with a gentle jet of air for 5 seconds; group 3, excess was removed with a dry microbrushtype device; and group 4, a gentle jet of air was applied after the microbrush and then light activation was performed. After this, the teeth were submitted to microtensile testing. For the two systems tested, no statistical differences were observed between groups 1 and 2. Groups 3 and 4 presented higher bond strength values compared with the other studied groups, allowing the conclusion that excess adhesive removal with a dry microbrush could improve bond strength in composite restorations. Predominance of adhesive fracture and thicker adhesive layer were observed via scanning electron microscopy (SEM) in groups 1 and 2. For groups 3 and 4, a mixed failure pattern and thinner adhesive layer were verified. Clinicians should be aware that excess adhesive may negatively affect bond strength, whereas a thin, uniform adhesive layer appears to be favorable.
authors: Biomaterials Division, Faculty of Dentistry of Uberaba, University of Uberaba, Uberaba, MG, Brazil. fernando.menezes@uniube.br
authors: Fernando Carlos Hueb
authors: FC
authors: de Menezes
authors: Stella Borges
authors: SB
authors: da Silva
authors: Thiago Assunção
authors: TA
authors: Valentino
authors: Maria Angélica Hueb de Menezes
authors: MA
authors: Oliveira
authors: Alessandra Nara de Souza
authors: AN
authors: Rastelli
authors: Luciano de Souza
authors: Lde S
authors: Conçalves
mesh_terms: D000268:Adhesiveness; D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding; D003737:Dental Cavity Preparation / Q000145:classification; D003764:Dental Materials / Q000737:chemistry*; D003793:Dental Restoration, Permanent / Q000145:classification; D003799:Dental Stress Analysis / Q000295:instrumentation; D006801:Humans; D055115:Light-Curing of Dental Adhesives; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D019279:Resin Cements / Q000737:chemistry*; D013314:Stress, Mechanical; D013499:Surface Properties; D013718:Tensile Strength
chemical_list: C438313:Clearfil SE Bond; D003188:Composite Resins; D003764:Dental Materials; D019279:Resin Cements; C084018:Scotchbond Multi-Purpose; C533204:filtek Z350