The relationship between dentin bond strengths and dentin permeability

The relationship between dentin permeability and the shear bond strength of Scotchbond/Silux was investigated. In the presence of a smear layer, there was no correlation between dentin permeability and dentin bond strengths. After removal of the smear layer with acids, there was an inverse relationship between dentin permeability and dentin bond strength. The bond strengths were high when dentin permeability was low and decreased as dentin permeability increased. Creation of smear layers with abrasive paper or dental burs reduced permeability by 80-85%. When Scotchbond/Silux bonds were made to such smear layers and then broken, the permeability of the dentin remained low. If the smear layer was removed by acid-etching prior to bonding, the permeability increased. When these bonds were broken, the permeability of the dentin remained elevated.