Edition V07N04 | Year 2013 | Editorial Artigo Inédito | Pages 60 to 74
In the oral cavity, there are rigid (teeth) and resilient structures (soft tissue) that are reproduced and, unfortunately, present different behaviors when in contact with impression material: Rigid structures do not undergo deformation and can generate accurate copies; whereas resilient structures undergo deformations that need to be conveniently treated so that the prosthesis does not cause injuries to soft tissues. It is essential that implants be precisely transferred to the work models, thus favoring precise positioning of analogues and, as a result, providing the lab technician with the appropriate conditions to fabricate prosthetic pieces that are appropriately adapted to the mouth. We use screwed impression copings that are placed by means of the direct transfer technique. Models are fabricated in two steps: (I) anatomical impression with stock tray and use of impression material of different consistencies, in layers; (II) functional impression carried out with customized tray and polyether or addition-cured silicones with different flows, in layers. After curing the impression material, excesses are removed and the impression copings are fixed to the customized acrylic tray with low shrinkage resin by means of the brush technique. After the impression material is cured, the impression copings are unscrewed and the model is removed from the oral cavity. The anatomical and functional transfer of multiple implants is essential for obtaining faithful models on which prostheses, which properly fit on implants with proper contact with soft tissues, are built, thus preventing potential injuries.