Chemical Characterization of the Resin-Dentin Interface by Micro-Raman Spectroscopy

Abstract

The chemical nature of the interface between dentin and adhesive resin materials was characterized by micro-Raman spectroscopy. The resulting chemical profiles were correlated with photomicrographs obtained by SEM after an argon-ion-beam etching treatment of the sample surface. Two commercially available dentin adhesive systems, of which one was also applied with a different conditioning agent, were investigated. Raman spectra, which were recorded along line scans across the interface with a step increment of 1 micron, revealed that resin effectively penetrated 4 to 6 microns deep into the superficially decalcified dentin zone. Across the interface, a gradual transition from resin to dentin over the interdiffusion zone with a mixed contribution of both substances was noticed. Finally, resin appeared to penetrate to the entire decalcification depth of dentin regardless of the aggressiveness of the conditioning procedure.

Marginal and internal adaptation of class II restorations after immediate or delayed composite placement

“…The micro-morphology of the internal adhesive interface, as shown on the gold-sputtered resin replicas, is compatible with the description made by Nakabyashi, Pashley and Van Meerbeck [44,52,53]. SEM observation of sample sections at higher magnification revealed that adhesive failures chiefly occurred above the hybrid layer and predominantly where resin tag formation was insufficient.…”

“…The importance of the elastic layer has been shown as early as 1990 [21,22]; since then, several studies confirmed the validity of this concept [10,12,40,42,43]. A last potential explanation for the inferior efficiency of such a one bottle adhesive is an insufficient or total lack of polymerization of the very thin resin layer left after adhesive placement and solvent evaporation (only a few microns) [44]. Actually, the inhibitory effect of oxygen is known to affect resin polymerization to a depth of 100 mm or more and to create a layer of totally non-polymerized resin of about 15 mm [45].…”

Multiscale mechanics of hierarchical structure/property relationships in calcified tissues and tissue/material interfaces

“…The Raman spectral bands collected as a function of position across the d/a interface also showed a gradual decrease in adhesive concentration. Gradual decreases in intensity of Raman bands associated with adhesive have been reported previously [132,133], but in these studies, the authors measured the amount of resin penetration based on the absolute intensity of adhesive bands [133], totally ignoring the collagen matrix, the key component of acid-etched dentin. The absolute intensity of backscattering Raman band is dramatically effected by many factors, such as the smoothness of the sample surface, the position of focusing, the depth of detection, fluorescence of biological components and the stability of the instrument and laser power, etc.…”

Effect of Thermocycling on Interfacial Gap-formation in Class V Cavities and Mechanical Properties of Spherical Silica Filler Addition to Resin-modified Glass Ionomer Restorations

“…Since silica fillers do not shrink, previous studies have shown that the addition of spherical silica fillers served to reduce the sum of interfacial gaps in the immediate condition as well as significantly improved the mechanical strength of RMGICs 4,5 . Apart from the contributory factor of silica filler, the factor of water uptake into the RMGIC matrix to form a poly-HEMA complex would contribute to eliminating the marginal gaps too 3,26 .…”