Effect of carbamide peroxide bleaching on the sheer bond strength of composite to dental bonding agent enhanced enamel

Statement of problem. Carbamide peroxide bleaching has been implicated in a dversely affecting the bond strength of composite to enamel. Purpose. This in vitro study evaluated the effect of 3 dental bonding agent s (OptiBond, All-Bond 2, One-Step) on the shear bond strength of a. hybrid composite: to enamel which was treated by a. 10% carbamide peroxide bleachi ng system. Material and Methods. Cylinders of composite were bonded to carbamide perox ide-treated enamel on extracted human teeth using 3 dental bonding agents. After thermocycling, shear bond strengths were determined with 3 universal testing: machine. Results. OptiBond aided bond strength were 23.7 +/- 5.6 Mpa to bleached and 19.6 +/- 2.9 MPa to unbleached enamel. For All-Bond 2, bleached enamel exh ibited bond strengths of 14.9 +/- 4.0 MPa and unbleached enamel exhibited a . bond strength value of 20.4 +/- 2.3 MPa. The composite bond strength for One-Step was 13.6 +/- 5.9 MPa to bleached and 23.0 +/- 3.9 MPa to unbleache d enamel. There was no statistical difference between OptiBond (alcohol bas e) aided bond strengths for bleached and unbleached enamel however, the bon d strength of composite to bleached enamel with All-Bond 2 or One-Step (ace tone base) was significantly lower than unbleached controls. Conclusion. The effect of bonding agent usage on composite bond strength to enamel bleached with a particular carbamide peroxide was dependent on the bonding agent used.