DEFECTS IN AUTOMIXED ADDITION SILICONE ELASTOMERS PREPARED BY PUTTY-WASH IMPRESSION TECHNIQUE

Voids presenting in impressions of five automixed addition silicone elastomers were investigated. Impressions were prepared with the putty-light body impression technique on stainless-steel cylinders with acrylic spacers. The number of voids was counted at a predetermined site on three separate days using a stereomicroscope at x 7 magnification. Impression specimens of a hand-mixed addition silicone, and from hand-mixing of the automixed materials, were made for comparison. Express gave a significantly higher number of voids than other automixed materials, with President Jet having the lowest void count. Automixed materials generally produced impressions with significantly fewer voids than the hand-mixed material. Automixing was effective in reducing void defects in elastomeric impressions.