Effect of preliminary treatment of the dentin surface on the shear bond strength of resin composite to dentin

This study evaluated the effect of two dentin disinfectants (Consepsis, Tub ulicid), one aqueous BEAM solution (Aqua Prep), a combination of Aqua Prep and Tubulicid and an air abrasion treatment (50 mum aluminum oxide) on the shear bond strength (SBS) of two acetone-based single bottle adhesives (One Step and Prime & Bond 2.1). The occlusal surfaces of 167 freshly extracted human third molars were ground flat to expose the dentin, then polished wi th a 600 grit-polishing disc. The teeth were randomly assigned to 12 test g roups (two bonding agents, six pretreatment protocols). The exposed dentin was etched with 35% phosphoric acid for 20 seconds, rinsed and briefly (1-2 seconds) air dried. Six pretreatment protocols were then applied. The air abrasion groups were exceptional, as etching was carried out only after pre treatment. One Step, or Prime & Bond 2.1 was applied according to the manuf acturer's instructions. Cylinders of Z-100 composite were bonded to the fla t dentin surfaces by transparent gelatin capsules. Specimens were thermocyc led in water baths between 5 degrees and 55 degreesC, then sheared in an In stron Testing Machine. One-way and two-way ANOVA and Tukey HSD post-hoc tes ts were used for statistical analysis. In the One Step group, Consepsis yie lded a significantly higher SBS (17.8 MPa) than air abrasion (9.5 MPa), Con trol (11.8 MPa) and Aqua Prep + Tubilicid (11.9 MPa), and a comparable SBS with Tubilicid (12.5 MPa) and Aqua Prep (14.8 MPa). In the Prime & Bond 2.1 group, Aqua Prep (24.9 MPa) showed a significantly higher SBS than all oth er groups: air abrasion (9.3 MPa), Control (9.97 MPa), Tubilicid (12.2 MPa) , Consepsis (13.0 MPa) and Tubilicid +Aqua Prep (13.3 MPa).