title: Do the microshear test variables affect the bond strength values?
abstract: Little is known about the effect of specimen preparation and testing protocols on the micro-shear bond strength (μSBS) results. To evaluate whether variations in polyethylene rod use affect (μSBS)). Human dentin disks were randomly distributed into six groups (n = 5): polyethylene tube (3 levels) and adhesive system (2 levels). In Group 1, polyethylene tubes filled with polymerized composite) were placed on adhesive covered surfaces. Tubes were removed 24 h after water storage, leaving the rods only. In Group 2, the same procedure was performed; however, tubes were kept in place during testing. In Group 3, composite rods without tubes were placed on adhesive covered dentin. In all groups, adhesives were photoactivated after positioning filled tubes/rods on adhesive covered surfaces. Specimens were tested under shear mode and the data subjected to a two-way ANOVA and Tukey's tests. Groups 1 and 2 resulted in statistically similar mean μSBS (P > 0.05); however, a greater number of pretest failures were observed for Group 1. Higher μSBS values were detected for Group 3, irrespective of adhesive system used (P < 0.05). Removing the polyethylene tube before composite rod is placed on dentin affects μSBS values.
authors.affiliation: Department of Biomaterials and Oral Biology, School of Dentistry, University of São Paulo, Cidade Universitária, 05508-000 São Paulo, SP, Brazil.
authors.forename: Andrea M
authors.initials: AM
authors.lastname: Andrade
authors.forename: Eugenio
authors.initials: E
authors.lastname: Garcia
authors.forename: Sandra Kiss
authors.initials: SK
authors.lastname: Moura
authors.forename: Alessandra
authors.initials: A
authors.lastname: Reis
authors.forename: Alessandro
authors.initials: A
authors.lastname: Loguercio
authors.forename: Luciana Mendonça
authors.initials: LM
authors.lastname: Silva
authors.forename: Gustavo H D
authors.initials: GH
authors.lastname: Pimentel
authors.forename: Rosa Helena Miranda
authors.initials: RH
authors.lastname: Grande