Light-activation of resin cement through ceramic: Relationship between irradiance intensity and bond strength to dentin
✍ Scribed by Rafael R. Moraes; Lourenço Correr-Sobrinho; Mário A. C. Sinhoreti; Regina M. Puppin-Rontani; Fabrício A. Ogliari; Evandro Piva
- Publisher
- John Wiley and Sons
- Year
- 2008
- Tongue
- English
- Weight
- 304 KB
- Volume
- 85B
- Category
- Article
- ISSN
- 1552-4973
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✦ Synopsis
Abstract
This study investigated the relationship between the irradiance transmitted through ceramic and the bond strength of a resin cement to dentin. After application of an adhesive system, elastomer molds with cylindrical orifices (1.2 mm in diameter) were placed onto bovine dentin surfaces and filled with a photoactivated luting agent (Enforce; Dentsply Caulk). Light‐activation was performed through a 0.6‐mm‐thick ceramic disc using different intensities: 250, 400, 550, 700, or 850 mW/cm^2^. Control specimens were irradiated without ceramic (1050 mW/cm^2^). The radiant exposure was kept at 30 J/cm^2^. Light spectral distribution was analyzed with a spectrometer. Microshear test was conducted and modes of failure were classified under SEM. Bond strength data were analyzed with ANOVA and Student–Newman–Keuls' test (α ≤ 0.05), and failure scores with the Kruskal–Wallis test (α ≤ 0.05). A linear regression model assessed the relationship between irradiance and bond strength. Groups light‐cured at 250 and 400 mW/cm^2^ presented lower bond strengths than groups activated at 850 and 1050 mW/cm^2^. The linear regression showed that a decrease in light irradiance predicts a decrease in bond strength (r^2^ = 0.955; p = 0.004). A predominance of mixed failures was observed. No significant alteration in the spectral wavelengths was observed. Despite the constant energy dose, the bond strength was dependent upon the irradiance level. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008