title: Influence of additional adhesive application on the microtensile bond strength of adhesive systems.
abstract: This study evaluated microtensile bond strength (pTBS) when an additional adhesive layer was applied to the dentin surface. Thirty-five human third molars were flattened to expose the occlusal dentin surface. The teeth were randomly assigned to 7 experimental groups: G1-Single Bond (SB); G2-additional layer of SB; G3--a layer of Scotchbond Multi-purpose (SMP) adhesive applied over SB; G4-Clearfil SE Bond (CE); G5-additional layer of CE; G6-Adper Prompt (AP) and G7-additional layer of AP. For the G2, G3, G5 and G7 groups, the first adhesive layer was light-cured before application of the additional layer. After bonding procedures, 5-mm high composite crowns were incrementally built up. The samples were sectioned to obtain 0.9 x 0.9 beams, which were tested under tension at a crosshead speed of 0.5-mm/minute until failure. The failure mode and adhesive thickness were evaluated under SEM. The pTBS data were analyzed by 1-way ANOVA and post-hoc Ducan's Test (a=0.05). Mean adhesive thickness was analyzed by 1-way ANOVA and post-hoc Tukey's test (a=0.05). The results indicated that G3 presented the highest microTBS and the thickest adhesive layer. G6 and G7 presented the lowest microTBS values. When solvent-free adhesives systems were used, microTBS values were not affected by the thicker layer.
authors.affiliation: Department of Restorative Dentistry, Piracicaba School of Dentistry, University of Campinas, Piracicaba, São Paulo, Brazil. andrelfs@fop.unicamp.br
authors.forename: André Luís Faria
authors.initials: AL
authors.lastname: de Silva
authors.forename: Débora Alves Nunes Leite
authors.initials: DA
authors.lastname: Lima
authors.forename: Grace Mendonça Dias
authors.initials: GM
authors.lastname: de Souza
authors.forename: Carlos Tadeu Dias
authors.initials: CT
authors.lastname: dos Santos
authors.forename: Luís Alexandre Maffei Sartini
authors.initials: LA
authors.lastname: Paulillo
mesh_terms: D000268:Adhesiveness; D000269:Adhesives / Q000737:chemistry; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding; D003793:Dental Restoration, Permanent / Q000379:methods; D003804:Dentin / Q000648:ultrastructure; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D008964:Molar, Third; D010755:Organophosphates / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013718:Tensile Strength
chemical_list: D000269:Adhesives; C489661:Adper Prompt Self-Etch; C438313:Clearfil SE Bond; D003188:Composite Resins; D017220:Dentin-Bonding Agents; D010755:Organophosphates; D019279:Resin Cements; C084018:Scotchbond Multi-Purpose; C467914:TPH spectrum; C115612:single bond; D017438:Bisphenol A-Glycidyl Methacrylate