OBJECTIVE: The influence of light-curing of a one-step self-etch adhesive (1-SEA) prior to the application of different bonding agents (BA) on the micro-tensile bond strength (μTBS) to dentin after 24h and thermal cycling was investigated. Additionally, the degree of conversion was evaluated using Fourier-transform infrared spectroscopy. METHODS: Three ion-releasing BAs, BZF-21 (experimental BA), Clearfil SE Protect (CSP), and FL-Bond II (FL-II), were applied subsequently to G-Premio Bond (1-SEA, GPB). Prior to their application, GPB was either light-cured (10s, 1000mW/cm2) or remained uncured. GPB was used as a control and Clearfil SE Bond 2 (CSE2) as a gold-standard 2-step reference. After resin-composite build-up and 24-h water storage (24h), half of the specimens were subjected to 15,000 thermal cycles (TC). Then, the specimens were sectioned into beams and tested under tensile load (1mm/min). The acquired data were analyzed using a 2-way ANOVA and Student's t-test with Bonferroni correction, and a two-parameter Weibull analysis, α=0.05. RESULTS: The μTBS of GPB increased significantly in the uncured groups with BZF-21 (24h: p<0.001, TC: p<0.001) and CSP (24h: p=0.039, TC: p<0.001), and in the light-cured group with CSP after TC (p=0.044). The groups with FL-II were not significantly different from GPB (p=1). No significant difference was found between CSE2 and the uncured groups GPB+BZF-21 (24h: p=1, TC: p=0.452) and GPB+CSP (24h: p=0.671, TC: p=0.566). SIGNIFICANCE: BZF-21 and CSP improved the μTBS of GPB to dentin both immediately and after TC. Higher μTBSs were obtained when GPB remained uncured prior to BA application.

Department of Cariology and Operative Dentistry Graduate School of Medical and Dental Sciences Tokyo Medical and Dental University 1 5 45 Yushima Bunkyo ku Tokyo 113 8510 Japan

Department of Cariology and Operative Dentistry Graduate School of Medical and Dental Sciences Tokyo Medical and Dental University 1 5 45 Yushima Bunkyo ku Tokyo 113 8510 Japan; Biomaterials Department Faculty of Oral and Dental Medicine Modern University for Technology and Information Cairo Egypt

Department of Cariology and Operative Dentistry Graduate School of Medical and Dental Sciences Tokyo Medical and Dental University 1 5 45 Yushima Bunkyo ku Tokyo 113 8510 Japan; Institute of Dental Medicine 1st Faculty of Medicine of the Charles University and General University Hospital Prague Karlovo namesti 32 Prague 121 11 Czech Republic

Department of Oral Prosthetic Engineering Graduate School of Medical and Dental Sciences Tokyo Medical and Dental University 1 5 45 Yushima Bunkyo ku Tokyo 113 8510 Japan

Institute of Dental Medicine 1st Faculty of Medicine of the Charles University and General University Hospital Prague Karlovo namesti 32 Prague 121 11 Czech Republic

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