![]() As a result, one should choose an impression material accordingly. It is also paramount for the dentist to understand that not all impression materials and impression situations are the same. 2 Dental marketing seems to be focused on the concepts of hydrophilicity as if it were the only standard on which to judge the product. However, there are physical and mechanical characteristics which are far more critical to consider such as: detail reproduction, dimensional stability, ease of removal, gypsum (die and model stone) compatibility, elastic recovery/strain in compression, tear resistance, viscosity, complete conversion to an elastic solid, acceptable odor and taste, shelf life, and having the capability to be poured multiple times while still maintaining accuracy. 1 When evaluating an impression material, dentists tend to focus mainly on 3 factors:hydrophilicity, setting time, and cost. The elastic materials include: alginate (irreversible hydrocolloid), agar (reversible hydrocolloid), polysulfide, condensation silicone, addition silicone (polyvinyl siloxane ), and polyether. The nonelastic materials include: plaster, dental compound, and zinc oxide eugenol pastes. ![]() IMPRESSION MATERIALS Throughout the last 2 centuries, different types of impression materials have been developed for use in dentistry. ![]() The purpose of this article is to share material choice rationale and technique protocols that we use in our office for taking consistently accurate impressions. The good news is that taking great impressions can be simple if a dentist chooses the correct impression tray, achieves adequate retraction with controlled bleeding, and uses a rigid impression material with a light body wash to clearly capture every detail of the preparation. Unfortunately, for many clinicians, taking a crown and bridge impression is one of the most stressful procedures in restorative dentistry. ![]() I sometimes wonder if the restorations fabricated from today’s materials are as accurate, or will last as long? We all know that a meticulous impression is paramount for a precision fit of the permanent indirect restoration. Even now, we are still seeing the results of the “copper band masters” decades after the restoratons were placed. One has to only look back and visualize copper band impressions taken with dental compound, and picture the definition, accuracy, margin detail, and meticulous dies that these impressions provided. This is especially true for crown and bridge impression materials and techniques. Sometimes, I feel that the “prehistoric” techniques that we learned in dental school years ago display more benefits than what is in vogue today. INTRODUCTION Today’s dentists are exposed to a multitude of dental materials, with each manufacturer claiming the benefits and superiorities of its respective products. ![]()
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