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.
A simple technique for impression taking of teeth and functionally generated paths
The objective of this case report is to introduce a simple technique for simultaneously taking a closed-mouth impression and functionally generated path (FGP) for a full coverage crown restoration. A monolithic zirconia crown was the restoration of choice. An alginate impression of the abutment tooth was taken to fabricate a custom-made closed-mouth impression tray covering the abutment tooth and the adjacent teeth. The tray had an FGP table and an abutment tray in cameo and intaglio surfaces, respectively. The impression was taken with silicone impression material after adjusting the abutment tray and inscribing the FGP using self-curing acrylic resins. Plaster casts were made from the impression, and a zirconia crown was fabricated. The crown was cemented to the abutment tooth with minimal adjustments. This simple technique resulted in a well-fitting crown that accounted for mandibular movements. Using the custom closed-mouth impression tray incorporating an FGP table simultaneously aids in fabricating an accurately fitting restoration that incorporates harmonious mandibular movements using a single impression capture.
The prosthodontic use of endodontically treated teeth: theory and biomechanics of post preparation.
It is impossible to state that any given system is better than another system for any and all situations. In all systems it is advisable to leave at least 3 to 5 mm of root canal filling to preserve the integrity of the apical seal. From a retentive standpoint, the parallel-sided posts have a greater retention than the tapering-sided posts but, because they are placed within a tapering root, they require more finesse on placement. In all teeth the length of the post is important since it is directly proportional to the amount of support offered by the post and its resistance to root fracture.