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Influence of oxygen‐inhibited layer on dentin bond strength of chemical‐cured resin composite
Author(s) -
Yamaji Ayumi,
Koga Kensaku,
Tsujimoto Akimasa,
Shimizu Yusuke,
Tsubota Keishi,
Takamizawa Toshiki,
Miyazaki Masashi
Publication year - 2013
Publication title -
european journal of oral sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.802
H-Index - 93
eISSN - 1600-0722
pISSN - 0909-8836
DOI - 10.1111/eos.12077
Subject(s) - dentin , adhesive , bond strength , oxygen , composite material , composite number , layer (electronics) , materials science , chemical bond , scanning electron microscope , contact angle , chemistry , organic chemistry
This study evaluated the influence of an oxygen‐inhibited layer on the surface free energies of three single‐step self‐etch adhesives and on the bond strength of chemical‐cured resin. Adhesives were applied to bovine dentin and light irradiated, and the oxygen‐inhibited layer was either retained or removed. Surface free energies were determined by measuring the contact angles of test liquids placed on the cured adhesives. Dentin bond strengths of chemical‐cured resin with and without the oxygen‐inhibited layer were measured. Ultrastructural observation of the restorative–dentin interface was made by scanning electron microscopy. For all surfaces, values of the estimated surface tension component, Lifshitz‐Van der Waals force (γ S LW ), were relatively constant. Values for the Lewis acid (γ S + ) component increased slightly when the oxygen‐inhibited layer was removed, whereas those of the Lewis base (γ S − ) component decreased significantly. The bond strength of the chemical‐cured resin composite was significantly higher in specimens without an oxygen‐inhibited layer (7.6–8.0 MPa) than in those with an oxygen‐inhibited layer (4.8–5.2 MPa). Small gaps between adhesive and resin composite were found for the group with an oxygen‐inhibited layer. These results indicate that the absence of an oxygen‐inhibited layer in single‐step self‐etch adhesives promotes higher dentin bond strength of the chemical‐cured resin.