On the interaction of polyacrylic acid as a conditioning agent with bovine enamel

In the present paper, the effects of polyacrylic acid (PAA) conditioning on the morphology and chemistry of bovine enamel surface and the resulting interfacial reactions are being investigated using photometric, microscopic (SEM, AFM), electron spectroscopic (XPS) and staining methods (neutral red dye). The results are compared to two reference surfaces obtained by simple grinding and by etching with a phosphoric acid solution. It is shown that PAA conditioning leads to the leaching of calcium and phosphorus ions, to the smoothening of the surface and probably to the formation of a polymeric film at the surface. A mechanism by which a preliminary PAA conditioning of the enamel leads to the reported higher bonding strength between enamel and glass ionomer cements is proposed.