PURPOSE: To evaluate the shear bond strength to dentin of fluoride-releasing materials. MATERIALS AND METHODS: Human, noncarious extracted permanent molars stored in distilled water were used. Flat buccal and lingual dentin surfaces were ground wet on 600-grit silicon carbide paper. The teeth were then distributed at random into four groups of 5 teeth (10 surfaces) each: Group 1: Fuji II LC; Group 2: Vitremer; Group 3: VariGlass; Group 4: Dyract. Cylindrical samples of the glass ionomers were prepared in plastic molds and bonded to the dentin surface according to the manufacturers' instructions. All samples were placed in distilled water for 24 hours, thermocycled for 500 cycles in distilled water at 5 degrees C and 55 degrees C and sheared with an Instron at a crosshead speed of 0.5 mm/minute. RESULTS: In MPa: Group 1: 15.96 +/- 3.28; Group 2: 9.70 +/- 2.43; Group 3: 13.48 +/- 3.35; Group 4: 21.14 +/- 5.32. ANOVA revealed that Dyract had a significantly higher bond strength than all the other products tested (P < 0.0001). Vitremer had a significantly lower bond strength. Fuji II LC had no significant difference from VariGlass. Fracture patterns, examined with the SEM, were cohesive within the cement for all groups.
PURPOSE: To evaluate the shear bond strength to dentin of fluoride-releasing materials. MATERIALS AND METHODS:Human, noncarious extracted permanent molars stored in distilled water were used. Flat buccal and lingual dentin surfaces were ground wet on 600-grit silicon carbide paper. The teeth were then distributed at random into four groups of 5 teeth (10 surfaces) each: Group 1: Fuji II LC; Group 2: Vitremer; Group 3: VariGlass; Group 4: Dyract. Cylindrical samples of the glass ionomers were prepared in plastic molds and bonded to the dentin surface according to the manufacturers' instructions. All samples were placed in distilled water for 24 hours, thermocycled for 500 cycles in distilled water at 5 degrees C and 55 degrees C and sheared with an Instron at a crosshead speed of 0.5 mm/minute. RESULTS: In MPa: Group 1: 15.96 +/- 3.28; Group 2: 9.70 +/- 2.43; Group 3: 13.48 +/- 3.35; Group 4: 21.14 +/- 5.32. ANOVA revealed that Dyract had a significantly higher bond strength than all the other products tested (P < 0.0001). Vitremer had a significantly lower bond strength. Fuji II LC had no significant difference from VariGlass. Fracture patterns, examined with the SEM, were cohesive within the cement for all groups.