The effects of air-abrasion on dentin, enamel, and metal bonding

Purpose: To determine the most effective emission pressure for producing effective bond strengths of an adhesive resin to enamel, dentin and metal. Methods: Test specimens were prepared from bovine teeth for enamel and dentin samples and from alloy disks cast in an Ag-Pd-Cu-Au alloy. All specimen substrates were ground flat and finished with 600-grit SiC paper. The prepared specimens were randomly divided into groups of eight including a control (no abrasion) or air-abraded with 50 mum Al2O3 delivered at three emission pressures of 60, 45 and 30 psi, respectively. Following conditioning, 4-META/MMA-TBB resin was bonded to the specimen surfaces. Specimens were stored in 37degreesC water for 24 hours, then thermocycled 20,000 times (4degreesC-60degreesC), and shear bond tested. Data were analyzed by ANOVA for statistical significance. Results: Enamel specimens showed no statistically significant difference from the control (no air abrasion). Dentin specimens displayed a significant difference from control at 60 and 45 psi, but no significant difference from the control at 30 psi. Alloy specimens showed significantly higher bond strengths from the control at all emission pressures (P< 0.05).