Analysis of the dentin-resin interface by use of laser Raman spectroscopy.
OBJECTIVE
Adhesion of resin-bonding agents to dentin is currently believed to result from impregnation of adhesive resin into superficially demineralized dentin. The purpose of this study was to investigate the chemical composition of the resin-impregnated dentin (hybrid) layer using a micro-Raman spectroscopy.


METHODS
Resin composites were bonded to bovine dentin with the two-step bonding systems, and specimens were sectioned parallel to dentinal tubules. These surfaces were then polished down to 1 microm diamond pastes. Raman spectra were successively recorded along a line perpendicular to the dentin-adhesive interface by steps of 0.2 microm on a computer controlled X-Y stage. The relative amounts of hydroxyapatite (960 cm(-1), P-O), adhesive resin (640 cm(-1), aromatic ring), and organic substrate (1450 cm(-1), C-H) in the dentin-adhesive bonding area were calculated.


RESULTS
From the Raman spectroscopy results, the hybrid layer represents a gradual transition in the relative amount of adhesive from the resin side to dentin side. Evidence of poor saturation of the adhesive resin in the demineralized dentin with the one-bottle adhesive system was detected.


CONCLUSIONS
From the results of this study, inhomogeneity of the hybrid layer composition was detected, and the degree of resin impregnation was found to be different between the bonding systems tested.
Miyazaki
M
M
Department of Operative Dentistry, Nihon University School of Dentistry, 1-8-13 Kanda Surugadai, Chiyoda-Ku, 101-8310, Tokyo, Japan. miyazaki-m@dent.nihon-u.ac.jp
Onose
H
H
Moore
B K
BK
D000818:Animals; D017438:Bisphenol A-Glycidyl Methacrylate; D002417:Cattle; D003188:Composite Resins; D001840:Dental Bonding; D003804:Dentin / Q000737:chemistry; D003806:Dentin Permeability; D017220:Dentin-Bonding Agents; D019279:Resin Cements; D012822:Silicon Dioxide; D013059:Spectrum Analysis, Raman; D015040:Zirconium
D003188:Composite Resins; D017220:Dentin-Bonding Agents; C452442:Mac Bond II; D019279:Resin Cements; C083568:Z100 composite resin; C086113:palfique estelite; C115612:single bond; D017438:Bisphenol A-Glycidyl Methacrylate; D012822:Silicon Dioxide; D015040:Zirconium