Microleakage of dentin-bonded crowns placed with different luting materials

To assess the microleakage of dentin-bonded porcelain crowns placed with three different luting materials.

Standardized full-coverage crown preparations were made on 45 extracted premolar teeth of a design which was considered typical of the minimal preparation indicated for dentin-bonded crowns. Half of the margin of the crown was placed below the cemento-enamel junction. Impressions of the prepared teeth were made and individual crowns constructed in feldspathic porcelain. The interior surface of each crown was etched with Mirage Superetch and treated with silane bond-enhancing solution. The crowns were cemented using one of the following combinations: Group A, Scotchbond Multi-Purpose Plus (SBMP)/3M Ceramic Luting Kit; Group B, Mirage ABC/FLC, and Group C, All-Bond 2/DuoLink. The teeth were stored for 2 weeks at 37 degrees C, subsequently thermocycled, and the restorations examined for leakage using buffered methylene blue as the marker. The teeth were sectioned bucco-lingually through the restoration and the degree of microleakage assessed microscopically.

All groups showed leakage at the dentin and enamel margins and at the restoration-cement interface. There were significant differences in leakage at the enamel margins for the three groups (P = 0.007) but not at the margins finished in dentin (P = 0.762). There was a significant difference in leakage between Groups B and C at the enamel margin (P = 0.009) and, within Group B, significantly greater leakage at the enamel-restoration interface than the dentin-restoration interface (P = 0.033). There were no other significant interactions. At the restoration-adhesive interface there was no significant difference in leakage among the groups.