Effect of Mirage Bond primer on microleakage of resin composite restorations

This in vitro study assessed the microleakage of Class V restorations using Mirage Bond (NPG-PMDM) with a hybrid light polymerized resin composite. Restorations were inserted in cavities prepared in extracted human premolars using either bulk or incremental packing and with or without an intermediary unfilled resin. The enamel margin of each tooth was etched only with the primer. The teeth were stored for 1 week at 37 degrees C, thermocycled, and the restorations examined for leakage using methylene blue dye. The teeth were sectioned mesiodistally through the restorations and the microleakage assessed visually. All groups exhibited leakage at the gingival margin, but there was a significant difference between the cavities restored by bulk packing of the resin composite. Application of the intermediary resin did not diminish microleakage (P less than 0.01). Nevertheless, there were no other significant differences in microleakage between the groups (P greater than 0.05).