Adhesive properties of several impression material systems: Part II.

The effect of saliva contamination on the tensile adhesive bond strengths of four impression adhesive systems, (1) polysulfide, (2) polyether, (3) polyvinylsiloxane, and (4) condensation silicone impression adhesive, was studied. Standard acrylic resin tray samples of 1-inch square surface were made. Tray surfaces were contaminated with saliva either before or after the application of tray adhesives. Tensile tests were performed with a Universal Load testing machine. The tensile adhesive bond strengths of contaminated tray surface and contaminated adhesive were compared with a group of control. Contamination of all impression adhesives resulted in significantly lower bond strength. Except for the polyvinylsiloxane and polysulfide impression adhesive systems, saliva contamination of tray material significantly decreased adhesive bond strengths. Impression trays should be tried in the mouth, rinsed, and dried before adhesive is applied.