Some bonding characteristics of a HEMA/maleic acid adhesion promoter

A recently released dentine adhesion promoter, based on a HEMA/maleic acid primer, was found to bond exceptionally well to dentine (14.1 MPa) if the adhesion promoter layer was applied thickly enough. Air inhibition of the promoter layer during its initial cure was seen to reduce the bond strength by a half if the promoter layer was air-thinned prior to curing. The adhesion promoter was found to greatly enhance the bond strength of composite to glass ionomer, removing the necessity to acid etch the glass ionomer prior to applying the composite. The failure of the composite/glass ionomer bond was always within the glass-ionomer cement itself, with the higher bond strengths resulting in a greater incidence of oblique cracks at 45 degrees to the bond surface than had been previously observed.