An in vitro microleakage study of the 'bonded-base' restorative technique

Microleakage associated with a silver-reinforced restorative glass-ionomer cement (Hi-Dense) used with a composite resin (Z100) in a modified Class II bonded-base technique restoration was evaluated. The influence of long-term artificial saliva storage, thermal and load cycling was also determined. Class II composite (Z100) restorations used with a new dental adhesive system (Scotchbond Multi-Purpose Dental Adhesive) were used as controls. Results showed that the bonded-base technique can reduce the leakage observed with the direct composite technique. Thermocycling decreased the leakage at the composite-enamel interface but had no effect on the leakage at the composite-dentine interface or on the leakage patterns of bonded-base restorations. Load cycling had no significant influence on leakage patterns of either type of restorative mode. Storage in artificial saliva resulted in decreased leakage at the composite-enamel interface but had a minor adverse effect at the glass-ionomer-dentine interface.