Abstract

Background: Recently, erbium: yttrium aluminum garnet (Er: YAG) laser used for tooth preparation and silorane-based composite is a new material in dentistry so that the purpose of this study is to compare microtensile bond strength (MTBS) of silorane- based adhesive and composite (Filtek P90 silorane, 3M/USA) to dentin by Er: YAG laser irradiation versus bur cut. Materials and Methods: A total of 40 extracted human molars were flattened to obtain dentin surfaces. Mid-coronal dentin was prepared to adhesion process. The dentin (D) specimens were divided into 4 groups, according to the surface treatments: (1) D1: Laser preparation + acid etching + composite. (2) D2: Laser preparation + composite. (3) D3: Bur preparation + acid etching + composite. (4) D4: Bur preparation + composite. After application of primer and adhesive, composite builtups were created with a silorane-based composite. The composite material was irradiated with light cure (Demi/kerr/USA) for 40s. Specimens were sectioned into serial 1 mm2 sticks hour glass and MTBS was measured with universal testing machine in all sticks, 20 sticks for every group. MTBS test data were analyzed by ANOVA and post-hoc (Sheffe) test. Failure modes were determined under a stereomicroscope (ZTX-3E, Zhejiang/China) (X20). Failure mode distributions were analyzed by ANOVA. Results: In groups, group D3 showed the highest MTBS and groups D3, D4 that prepared by bur, showed higher bond strength results with a significant difference, than Er: YAG laser groups (D1,D2). Analysis of failure mode showed that predominantly adhesive for all tested groups. Conclusion: According to the results of this study bur preparation is preferred than laser in dentin.