ADHESION AND MICROLEAKAGE TESTS OF A NEW DENTIN BONDING SYSTEM

Adhesion to dentin and microleakage of a new dentin bonding system was studied. The new system includes a low viscosity lightly filled Bis-G MA based resin liner which is placed between the phosphate ester-conta ining adhesive layer and the composite. This system was compared to de ntin bonding agents based on: 1) HEMA and Bis-GMA and 2) PMDM and NTG- GMA. The phosphate ester system was used with and without the low visc osity resin. Each system was used with its corresponding posterior com posite. All groups were tested by shear and tensile bond testing immed iately and up to 6 mon after bonding. Microleakage of the three system s was tested in Class V restorations by dye penetration. The results o f the shear and tensile tests indicated that significant changes withi n groups occurred with time, and significant differences appeared betw een groups at various times. The use of low viscosity resin with the p hosphate ester system resulted in decreased leakage. The amount of lea kage observed was related to early shear bond strength. This study sug gests that the properties of the layer immediately adjacent to the adh esive may affect the performance of the system.