Abstract
Working casts were produced using three types of impression technique and impression material used for impression in the Branemark implant system, and the distortion of these casts was measured with a three-dimensional coordinate measuring machine. The three techniques were a technique in which a gold cylinder is splinted with autopolymerizing acrylic resin (gold-cylinder technique), a technique using squared impression coping (squared technique) and a technique using tapered impression coping (tapered technique). The three types of material were Examix Injection Type (Examix), Impregum F (Impregum), and Aroma Fine (Aroma). Based on the measurements, abutment replica distance, angle and height, which are considered the conditions of fit for the superstructure, were calulated by analytical geometry. The dimensional accuracy of the casts fabricated with each technique and material was compared.
1. The abutment replica distance was influenced by the impression technique. At all measured abutment replica distance sites, distortion of the gold cylinder technique and squared technique was less than the tapered technique.
2. The abutment replica angle was strongly influenced by the impression technique. At all measured abutment replica angle sites, distortion of the gold cylinder technique and the squared technique was less than the tapered technique.
3. Concerning the abutment replica height, result of using the tapered technique varied greatly. At all measured abutment replica height sites, distortion of the gold cylinder technique was less than the squared technique.
4. The impression material had no effect on the abutment replica distance or angle. At 2 of the 4 measured abutment replica height sites, distortion of Impregum was less than Aroma when the gold cylinder technique or squared technique was used.
5. The impression material had less effect on the dimension accuracy of working casts than the impression technique.
6. The use of the gold cylinder technique and Impregum provided working casts of high dimensional accuracy.
