The Effect of Carbamide Peroxide Bleaching Gel Containing Remineralization Agents on the Bond Strength of Universal Adhesives to Enamel

Background: The aim of this study was to examine the effect of carbamide peroxide bleaching gel containing remineralization agents on the bond strength of universal adhesives to enamel.

Materials and Methods: One hundred and thirty five extracted human third molars were divided into five groups to receive treatments during 14 days, as follows: no bleaching treatment (control group); 10% carbamide peroxide (CP); 10% CP containing 0.11% fluoride; 10% CP containing CPP-ACP; and 10% CP containing CPP-ACP and 0.11% fluoride. The buccal surfaces of all teeth were etched with 37% phosphoric acid, and each group was devided into three subgroups to receive the adhesive resins: All Bond Universal; Scotchbond Universal and Adper Single Bond 2. Then restored teeth were sectioned to create resin–enamel beams. These beams were subjected to the micro-tensile bond strength (μTBS) test, and assessed for failure mode under scanning electron microscopy.

Results: The highest mean μTBS of the composite resin to enamel was observed in the control group (25.9 MPa) and the lowest in the fluoride-containing bleaching group (17.2 MPa). Adper Single Bond 2 adhesive subgroups have the highest μTBS (19.7 MPa) and All Bond Universal adhesive subgroups have the lowest μTBS (16.8 MPa).

Conclusion: Oxygen negatively affects the polymerization of resins and adhesives. In cases where the teeth have been bleached, it is suggested waiting at least two weeks after the bleaching before completing an enamel bonded restoration to minimize the presence of remaining incorporated oxygen in the enamel. Inclusion of CPP-ACP in a fluoride containing bleaching agent minimizes the negative effect of the fluoride.

Keywords: Bleaching agents; remineralization agents; bond strength; universal adhesives.