Polymer Network Structure of Bonding Resin By Fluorescence Microscopy

Published

January 1, 2000

Author(s)

K Komatsu, E S. Wu, Francis W. Wang, K Nemoto

Abstract

The adhesive strength of a composite resin to dentin is generally affected by the polymer network structure of a bonding resin that is previously applied to primed dentin. This study aimed to investigate the effect of the polymer network structure of a photo-cured bonding resin on the adhesion between a composite resin and the dentin of a human tooth. Therefore, adhesive specimens with the bonding resin sandwiched between a composite resin and dentin was prepared using a bonding resin containing a fluorescent probe, AHPBS. The fluorescence spectra of the specimens were then measured by fluorescence microscopy. To prepare adhesive specimens, the dentin disk from a human tooth was polished with 600-grit sandpaper, and then etched with the mass fraction of 35 % phosphoric acid for 30 s. After applying a primer (the mass fraction of 30 % HEMA in water) to the demineralized dentin, a photo-cured bonding resin (Bis-GMA and HEMA) doped with AHPBS was applied and exposed to a curing light for 5 s. A photo-cured composite resin (Herculite XR, Kerr) was injected into a silicone mold with the treated dentin surface as its bottom, and then irradiated for 60 s. After embedding the specimen in a methacryl resin at 60 C for 24 h, the specimen was cross-sectioned. Then, the wetted specimen was polished with 600-grift sandpaper and stored in distilled water for 24 h. Fluorescence emission spectrum was measured with a laser at the excitation wavelength of 515 nm. The excitation laser was focussed, at 3 mm below the specimen surface where the beam diameter was 1 mm. The peak intensity at the interface of the bonding resin and dentin was very low, because the primer and the water in the demineralized dentin diluted the bonding resin. The fluorescence spectrum was obtained in the composite resin at a distance of 50 mm from the interface of the bonding rein and the composite resin, because the bonding resin diffused deeply into the uncured composite resin even after the exposure to light for 5 s. In addition, it was observed that the monomer in the composite resin also diffused into the bonding resin. It was concluded that the polymer network structure of the bonding resin between the composite resin and dentin was not homogenous because of the diffusion at the interfaces

Citation

International Association for Dental Research

Volume

79

Issue

Sp.

Pub Type

Journals

Keywords

bonding, dentin, fluorescent probe, polymerization, resin, structure 2 fluorescent probe

Citation

Komatsu, K. , Wu, E. , Wang, F. and Nemoto, K. (2000), Polymer Network Structure of Bonding Resin By Fluorescence Microscopy, International Association for Dental Research (Accessed April 23, 2024)