The variation in contact angle of fissure sealant on enamel surfaces

For strong adhesion of ultraviolet initiated polymeric fissure sealants to dental enamel, a well-formed tag structure is necessary. This requires that the unpolymerized sealant must be able to flow quickly into the etched surface before polymerization is initiated. The variation in contact angle, O, with time (the spreading ability) of unpolymerized Nuva-Seal has been measured on unetched, etched and moist enamel surfaces. This spreading ability varies with the condition of the surface. It is estimated that, in the system investigated, the roughness of the enamel surface is increased by up to 13% on etching, but is reduced again if moisture is present, due to condensation into the etch pits. An etched, moisture free enamel surface is therfore necessary for strong adhesion of polymeric materials.