Origination and progression of microleakage in a restoration with a smear layer-mediated dentinal bonding agent

Several recently marketed dentinai bonding agents modify, but do not remove, the smear layer. Some controversy exists as to whether the smear layer should be left in place or completely removed from preparations to be restored with composite resin systems. This study utilized scanning electron microscopy with energy dispersive x-ray analysis to evaluate the pathway of microleakage in a composite resin restorative material that utilizes a smear layer-mediated dentinai bonding agent. Microleakage occurred at the smear layer-denlin interface and progressed into both the smear layer and dentinai tubules, suggesting that the smear layer acts as a pathway for microleakage.