The Effect of Adhesive Material and Surface Roughness on the Tensile Bond Strength between Some Elastomeric Impression Materials and Cold Cure Acrylic

Abstract

: The detachment of impression materials from impression tray is considered as an important problem which is difficult to be detected clinically. Several attempts were used to handle this problem, as roughening the surface of the tray, perforating it, or by the use of adhesive solutions which are recommended to be used by manufacturers. Objectives: To determine the tensile bond strength of two elastomeric impression materials; polysulphide and polyether to cold-cure acrylic resin disks with or without tray adhesive application at different drying and surface treatment. Material and Methods: Eighty specimens prepared consisted of two disks with impression material sandwiched between, then divided into two groups; 40 specimens for each type of impression. The “PD” hold adhesive material was applied on the acrylic surfaces which were smooth and rough. The adhesive was allowed to dry for 2, 5, and 10 minutes before the application of impression materials. To determine tensile bond strength at the interface between the adhesive-acrylic, and the adhesive-impression materials, a universal Instron testing machine was used. Results: Polyether impression material showed higher tensile bond strength to cold-cure acrylic than polysulphide impression material, without adhesive application. However, after adhesive application, the bond strength to polyether decreased, while for polysulphide increased significantly. Roughening the acrylic surface significantly increased the bond strength for both impression materials with or without adhesive application. Also, increasing the drying time from 2 up to 10 minutes significantly increased the bond strength for both impression materials, and smooth and rough acrylic surfaces. Conclusions: Polyether impression showed higher bond strength to cold-cure acrylic than polysulphide impression, without adhesive application.