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Light‐activation of resin cement through ceramic: Relationship between irradiance intensity and bond strength to dentin
Author(s) -
Moraes Rafael R.,
CorrerSobrinho Lourenço,
Sinhoreti Mário A. C.,
PuppinRontani Regina M.,
Ogliari Fabrício A.,
Piva Evandro
Publication year - 2008
Publication title -
journal of biomedical materials research part b: applied biomaterials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.665
H-Index - 108
eISSN - 1552-4981
pISSN - 1552-4973
DOI - 10.1002/jbm.b.30928
Subject(s) - irradiance , bond strength , dentin , materials science , ceramic , composite material , adhesive , irradiation , light intensity , optics , physics , layer (electronics) , nuclear physics
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