A clinical scanning electron microscope study of tooth surface preparation and bonding

This clinical study utilized cut dentine surfaces on which the Creation Bond System and Scotchbond were applied after various surface treatments. It was observed under the scanning electron microscope that preparation with a tungsten carbide bur left a smear layer on the dentine. When this surface was pumiced, the smear layer remained and the tubules were plugged with smear debris. Polyacrylic acid and citric acid removed the smear layer from the dentine surface. When the Creation Bond System was applied to the surface treated with polyacrylic acid, hollow depressions were produced. Application of the Creation Bond System to the surface treated with citric acid resulted in some resin tag formation into the dentinal tubules as well as hollow depressions on the resin surface. The presence of these irregularities in the resin indicated fluid from the dentinal tubules prevented contact of the bonding resin with the dentine surface. This degree of contamination was not observed when Scotchbond was applied to a pumiced dentine surface.