Self-assembled Nano-layering at the Adhesive interface.
According to the 'Adhesion-Decalcification' concept, specific functional monomers within dental adhesives can ionically interact with hydroxyapatite (HAp). Such ionic bonding has been demonstrated for 10-methacryloyloxydecyl dihydrogen phosphate (MDP) to manifest in the form of self-assembled 'nano-layering'. However, it remained to be explored if such nano-layering also occurs on tooth tissue when commercial MDP-containing adhesives (Clearfil SE Bond, Kuraray; Scotchbond Universal, 3M ESPE) were applied following common clinical application protocols. We therefore characterized adhesive-dentin interfaces chemically, using x-ray diffraction (XRD) and energy-dispersive x-ray spectroscopy (EDS), and ultrastructurally, using (scanning) transmission electron microscopy (TEM/STEM). Both adhesives revealed nano-layering at the adhesive interface, not only within the hybrid layer but also, particularly for Clearfil SE Bond (Kuraray), extending into the adhesive layer. Since such self-assembled nano-layering of two 10-MDP molecules, joined by stable MDP-Ca salt formation, must make the adhesive interface more resistant to biodegradation, it may well explain the documented favorable clinical longevity of bonds produced by 10-MDP-based adhesives.
Department of Biomaterials, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Okayama, 700-8525, Japan. yasuhiro@md.okayama-u.ac.jp
Y
Y
Yoshida
K
K
Yoshihara
N
N
Nagaoka
S
S
Hayakawa
Y
Y
Torii
T
T
Ogawa
A
A
Osaka
B Van
BV
Meerbeek
D001840:Dental Bonding; D003804:Dentin / Q000648:ultrastructure*; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D017886:Durapatite / Q000737:chemistry*; D004577:Electron Probe Microanalysis; D006801:Humans; D008689:Methacrylates / Q000737:chemistry*; D017348:Microscopy, Electron, Scanning Transmission; D046529:Microscopy, Electron, Transmission; D049329:Nanostructures / Q000737:chemistry*; D019279:Resin Cements / Q000737:chemistry; D013052:Spectrometry, X-Ray Emission; D013499:Surface Properties; D014961:X-Ray Diffraction
C438313:Clearfil SE Bond; D017220:Dentin-Bonding Agents; D008689:Methacrylates; D019279:Resin Cements; C069749:methacryloyloxydecyl dihydrogen phosphate; C041330:Scotchbond; D017886:Durapatite