Influence of Activated Bleaching on Various Adhesive Restorative Systems DENIZ C. CAN-KARABULUT, DDS, PhD*, BARIS ¸ KARABULUT, DDS, PhD † ABSTRACT Statement of the Problem: When adhesive restorations are used in combination with bleaching in clinical applications, it is generally recommended to wait for a period of time between the two procedures. However, it is not clear if a time interval is necessary between applying the bleaching treatments and the silorane-based restorative system. Purpose: The purpose of this in vitro study was to determine if activated bleaching affects the bond strength of silorane-based restorative, a newly developed restorative that uses a polymerization system that has been reported to be insensitive to oxygen. Methods: A gel consisting of 38% hydrogen peroxide was applied to ground labial enamel surfaces and activated using a diode laser to bleach the teeth. Then, without waiting for any period of time, four different restorative materials were applied to the bleached enamel surfaces, and these sets were compared with nonbleached control samples. The shear bond strength of the restorative systems to enamel was tested, and data was evaluated using two-way analysis of variance and Tukey HSD tests. Results: Significant differences (p < 0.05) in shear bond strengths were found among bleached and nonbleached enamel surfaces. Conclusion: It may be more beneficial to allow a time interval of 2 to 3 weeks between activated hydrogen peroxide bleaching and applying silorane-based composite restoratives or methacrylate-based composites than just applying restorative agents immediately after bleaching. However, further studies are needed to examine the structural effects of activated hydrogen peroxide on enamel. CLINICAL SIGNIFICANCE A time interval should be allowed between the application of silorane-based or methacrylate-based restorations and activated hydrogen peroxide bleaching systems. (J Esthet Restor Dent 23:399–409, 2011) INTRODUCTION Bleaching may be indicated before restorative treatments in order to harmonize the shade of the restorative material with that of the natural teeth. 1 In fact, combining enamel bleaching and composite resin restoration procedures has been reported to achieve a more successful outcome. 2 Several studies have reported on bonding after bleaching. 3–9 Most of these studies 5–9 recommend waiting for a period of time between the bleaching procedures and the application of composite resins. The authors of one study 9 *Assistant Professor, Department of Operative Dentistry, Faculty of Dentistry, Near East University, Mersin 10,Turkey † Consultant, Department of Dentistry, Hospital of Girne, Mersin 10, Turkey ORIGINAL ARTICLE © 2011 Wiley Periodicals, Inc. DOI 10.1111/j.1708-8240.2011.00413.x Journal of Esthetic and Restorative Dentistry Vol 23 • No 6 • 399–408 • 2011 399