Gel phase formation at resin-modified glass-ionomer/tooth interfaces.
Ionic bonding between polyalkenoic acid and hydroxyapatite may explain the excellent bonding retention of glass-ionomers in clinical trials. We have here investigated the extent to which the self-adhesiveness of resin-modified glass-ionomers (RMGIs) can be attributed to this chemical bonding capacity. Therefore, the interaction of 3 RMGIs with tooth substrates was comprehensively characterized, with electron and atomic force microscopy correlated with x-ray photoelectron spectroscopy (XPS). Interfacial ultrastructural analysis for 2 RMGIs disclosed a shallow hybridization of hydroxyapatite-coated collagen, on which a submicron gel phase was deposited through reaction of the polyalkenoic acid with calcium extracted from the dentin surface. One RMGI, however, bonded to dentin without hybrid layer or gel phase formation. XPS indicated that polycarboxylic acids included in the RMGIs electrostatically interacted with hydroxyapatite. We conclude that the self-adhesiveness of RMGIs should be attributed to ionic bonding to hydroxyapatite around collagen, and to micro-mechanical interlocking for those RMGIs that additionally hybridize dentin.
Coutinho
E
E
Leuven BIOMAT Research Cluster, Department of Conservative Dentistry, School of Dentistry, Oral Pathology and Maxillo-Facial Surgery, Catholic University of Leuven, Leuven, Belgium.
Yoshida
Y
Y
Inoue
S
S
Fukuda
R
R
Snauwaert
J
J
Nakayama
Y
Y
De Munck
J
J
Lambrechts
P
P
Suzuki
K
K
Van Meerbeek
B
B
D000180:Acrylic Resins; D000268:Adhesiveness; D001840:Dental Bonding; D003806:Dentin Permeability; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D004577:Electron Probe Microanalysis; D005782:Gels; D005899:Glass Ionomer Cements / Q000737:chemistry*; D006801:Humans; D006882:Hydroxyapatites; D007474:Ion Exchange; D018625:Microscopy, Atomic Force; D008854:Microscopy, Electron; D044367:Phase Transition; D013499:Surface Properties
D000180:Acrylic Resins; D017220:Dentin-Bonding Agents; D005782:Gels; D005899:Glass Ionomer Cements; D006882:Hydroxyapatites; C510940:Ketac Dentin Conditioner; C088835:Photac-Bond; C067790:Vitrabond; C084541:Fuji glass-ionomer lining cement; C006903:carbopol 940