Dentin bonding: SEM evaluation of the glass ionomer-dentim interface

ABSTRACT

The purpose of this study was to evaluate the microstructure of the glass ionomerdentin interface after various dentin surface treatments, and to determine which treatment established a hybrid layer at this interface. Thirty sound extracted human teeth (permanent molars) were stored in a disinfectant solution (0.2 percent sodium azide). The occlusal enamel was removed, the dentin exposed and divided into two halves allowing two different dentin treatments in the same tooth. All teeth were mounted in a hydrostatic intrapulpal pressure apparatus, to simulate the in vivo conditions, and removed 12 hours after restorations had been completed. Groups were studied with regards to dentin surface conditioning 1) no dentin conditioning; 2) GC Conditioner; 3) Vitremer Primer; 4) 35 percent Phosphoric Acid + Vitremer Primer; 5) 35 percent Phosphoric Acid + Scotchbond Multi-Purpose Primer + Scotchbond Multi-Purpose Adhesive Resin. Standard procedures for preparing these specimens for SEM were utilized and the glass ionomer-dentin interface was evaluated under three different magnifications (300, 3000 and 13000 x). The presence and thickness of the hybrid layer was recorded for each specimen and a photomicrograph of a representative area was taken. The results indicated that the interfacial seal was more homogeneous when the dentin was conditioned with 35 percent Phosphoric Acid and either Vitremer Primer or Scotchbond Multi-Purpose was applied prior to the glass ionomer. This suggests that these two dentin treatments may provide better adhesion and less microleakage for glass ionomer restorations.