The aim of this study was to examine the effects of tray design and impression material on impression pressure in a clinical simulation model of an edentulous mandible. Two types of polyvinylsiloxane elastomer, one type of polyether elastomer, and one type of alginate were used. The three tray types had no relief, 0.36 mm of relief, or 1.4 mm of relief, with or without escape holes. Impression ...

introduction: complete adhesion of the impression materials to trays is important to prevent impression materials from being pulled away from trays during removed from the mouth and to ensure that the direction of polymerization shrinkage will be towards the tray. the aim of this study was to evaluate the effects of two retention features of custom trays (adhesive vs holes) on the dimensional a...

background: accurate impression making is an essential prerequisite for achieving a passive fi t between the implant and the superstructure. the aim of this in vitro study was to compare the three-dimensional accuracy of open-tray and three closed-tray impression techniques. materials and methods: three acrylic resin mandibular master models with four parallel implants were used: biohorizons (b...

PURPOSE The purpose of this study was to compare the accuracy of the implant master cast according to the type (pick-up, transfer) and the length (long, short) of the impression copings. MATERIALS AND METHODS The metal master cast was fabricated with three internal connection type implant analogs (Osstem GS III analog), embedded parallel and with 10° of mesial angulation to the center analog....

Background and Aims: An accurate impression of teeth and supporting structure is necessary to restore a lost tooth structure or to replace a tooth with crown and bridge. Although there are various methods for making impression, putty-wash technique is currently preferred since it is simple and does not require a special tray. Silicone elastomeric impression materials have suitable consistency f...

Certain simple visual displays consisting of moving 2-D geometric shapes can give rise to percepts with high-level properties such as causality and animacy. This article reviews recent research on such phenomena, which began with the classic work of Michotte and of Heider and Simmel. The importance of such phenomena stems in part from the fact that these interpretations seem to be largely perce...

Spatial thinking is a vital component of the science, technology, engineering, and mathematics curriculum. However, to date, broad development of learning environments that target domain-specific spatial thinking is incomplete. The present article visits the problem of improving spatial thinking by first reviewing the evidence that the human mind is embodied: that cognition, memory, and knowled...

PURPOSE A variety of impression trays are used in the fabrication of fixed indirect restorations. Impressions used in the construction of fixed indirect restorations were examined for tray type, manner of use, and overall impression quality. MATERIALS AND METHODS A commercial dental laboratory provided 1403 impressions used to fabricate fixed indirect restorations during a 3-month period. Imp...