AN IN-VITRO STUDY OF 2 ADHESIVE SYSTEMS - 3RD AND 4TH GENERATIONS

The aim of this in vitro study was to compare the adhesive properties of a manufacturer's third and fourth generation dentin adhesive. Vesti bular sections of recently extracted third molars were embedded in che mical-cured acrylic resin and ground with 600-grit silicon carbide san dpaper, Fifteen samples were prepared with the adhesive products and t he dentin surfaces were analysed by SEM. Twenty-four samples were divi ded into two groups and prepared with third and fourth generation syst ems, respectively. Composite filled tubes were then positioned on the prepared dentin surfaces and photopolymerized. The treated samples wer e kept in distilled water at 37 degrees C for 24 h. Four samples were used to analyze the resin-dentin surface. A tension test was performed on the remaining twenty samples at a crosshead speed of 0.5 mm/min. T he results were analyzed using the Fisher and Student t-tests. The fra ctured surfaces were examined by SEM. The resistance to tensile forces of specimens prepared with the fourth generation system was significa ntly higher than that obtained after using the third generation system . Thus, as expected from the in vitro tests, the fourth generation sys tem provided better adhesion to dentin than the third generation mater ial.