A review of contemporary impression materials and techniques.
The contemporary restorative dentist has a host of impression materials available for making impressions in fixed prosthodontics,implant dentistry, and operative dentistry. With proper material selection and manipulation, accurate impressions can be obtained for fabrication of tooth- and implant-supported restorations. This article outlines the ideal properties of impression materials and explains the importance of critical manipulative variables. Available impression materials are analyzed relative to these variables, and several "specialized" impression techniques are described. Special attention is paid to polyvinyl siloxane impression materials because they have become the most widely used impression material in restorative dentistry.
THE CUSTOM IMPLANT IMPRESSION COPING: TECHNICAL NOTE
Unsupported soft tissue can collapse around a submerged implant or abutment head during the time interval between removal of the provisional prosthesis and placement of the impression material. A technique is described for accurately recording the implant or abutment position as well as the position of the soft tissue for a single tooth restoration using the provisional prosthesis as a custom implant impression coping.
Dual-arch and custom tray impression accuracy.
This study compared the accuracy in three dimensions of casts made from complete-arch custom acrylic resin trays and two types of dual-arch impression trays. Using addition silicone impression material, 30 impressions (10/group) were made of a typodont. Reference marks on the typodont allowed measurements in the mesiodistal, buccolingual and occlusogingival dimensions. Gypsum casts were made and the distances between the reference marks on each cast were determined with a measuring microscope. The measurements from each cast were compared with one another and expressed as a percent deviation from the typodont measurements. Analysis with a two-way ANOVA and a Tukey B post hoc test established that the dual-arch trays were at least as accurate as the custom tray in every dimension measured.