Subsequent application of bonding agents to a one-step self-etch adhesive - Its effect with/without previous light-curing
Abstrakt
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 24 h 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 (10 s, 1000 mW/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 (24 h), half of the specimens were subjected to 15,000 thermal cycles (TC).
Then, the specimens were sectioned into beams and tested under tensile load (1 mm/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 (24 h: p < 0.001, TC: p < 0.001) and CSP (24 h: 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 (24 h: p = 1, TC: p = 0.452) and GPB + CSP (24 h: 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.