Effect of resins sealing of dentin on the bond strength of ceramic restorations

Abstract

Objectives: The purpose of this in vitro study was to evaluate shear bond strengths when ceramic cylinders were bonded to dentin following the use of different dentin adhesive systems as desensitizers. Methods: Freshly extracted human molars were selected. Their buccal dentin was exposed and a standardized circular area was isolated. Dentin desensitizers included an experimental self-curing ‘one-bottle’ adhesive system, two light-curing ‘one-bottle’ bonding systems and a conventional three component adhesive system, which was selected as a control system. Ten teeth were prepared for each test group (40 teeth total). A layer of an eugenol-free temporary cement was applied on the treated surface and the specimens were stored in distilled water for 1 week. After the removal of cement, the dentin surfaces were cleaned, re-etched and a layer of the experimental self-curing ‘one-bottle’ adhesive was applied. Standardized cylindrical ceramic samples were luted using a resin cement. One week later, shear bond strengths were determined using a universal testing machine. The bond strength values obtained were tested for a statistical significance with Kruskall–Wallis one-way analysis of variance. The type of failure occurring on each specimen was observed and recorded by means of an optical and a scanning electron microscope. Results: Mean shear bond strengths of the four groups ranged from 25.84 to 27.83 MPa and they were not significantly different. Most failures were cohesive in dentin. Significance: The use of an adhesive system as a dentin desensitizing agent before cementation does not alter the retentive strength of adhesively luted ceramic restorations.