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Overestimating hybrid layer quality in polished adhesive/dentin interfaces
Author(s) -
Wang Yong,
Spencer Paulette
Publication year - 2004
Publication title -
journal of biomedical materials research part a
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.849
H-Index - 150
eISSN - 1552-4965
pISSN - 1549-3296
DOI - 10.1002/jbm.a.20105
Subject(s) - materials science , dentin , adhesive , bleach , polishing , composite material , layer (electronics) , scanning electron microscope , morphology (biology) , smear layer , chemistry , organic chemistry , biology , genetics
The most popular techniques for determining the quality of the hybrid layer (HL) have relied on morphologic characterization of the polished adhesive/dentin (a/d) interfaces before and after acid‐bleach chemical treatment. Using these techniques, the existence of smooth, acid‐resistant layers has been consistently reported for most adhesive systems. The purpose of this study was to determine whether popular specimen preparation techniques that include polishing and acid‐bleach treatment modify the a/d interface, mask the complexity of the HL, and lead to inaccurate assessment of the quality of the HL. To understand the impact of specimen preparation techniques on the morphology of the resin–dentin interface, polished and unpolished specimens from the same tooth were closely compared after different acid‐bleach chemical treatment procedures. Two one‐bottle adhesives, that is, 3M Single Bond and Pulpdent UNO, exhibiting distinct differences in hydrophilic/hydrophobic composition, were used in this investigation. Using specimens from the same tooth, the effect of chemical treatments on the morphology of the resin–dentin interdiffusion zone and the differences in the morphology of polished and unpolished specimens after these same treatments were studied with scanning electron microscopy. It was shown that conventional specimen preparation techniques that include polishing and acid‐bleach treatment can adversely affect and even obscure the structural detail of the a/d interface in specimens that possess a porous HL. The results indicated that the Pulpdent UNO/dentin interface had better quality than the 3M Single Bond/dentin interface. The difference in the quality of HL can be attributed to factors such as compositional differences that impact the adhesive interaction with water, that is present within the substrate during wet bonding. The inability of the conventional acid‐bleach procedure to reveal the differences in the scanning electron microscopy interfacial morphology was overcome in this investigation by using a multistep technique. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 735–746, 2004