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Questions and Answers
What is the primary purpose of impression materials in dentistry?
What type of reproduction do impression materials create?
Which of the following types of trays is custom-made for a patient?
What form do some impression materials take before being used?
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What is one of the main functions of impression trays?
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What type of impression tray is typically prefabricated?
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What happens after the impression material has set?
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What are custom trays made from?
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What is the primary use of 3-bite registration trays?
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Which of the following is NOT an ideal requirement for an impression material?
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What type of impression materials are characterized by being rigid with little or no elasticity?
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What is a common disadvantage of impression plaster?
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Which of the following is an advantage of impression waxes?
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Impression compounds are primarily used for which group of patients?
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What is a key property of impression materials that allows easy removal from the mouth?
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What kind of impression materials soften on heating and harden upon cooling?
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Study Notes
Impression Materials Overview
- Impression materials register the form and relationship of teeth and oral tissues, creating accurate replicas or molds.
- Used for single teeth, full dentition, or edentulous mouths, producing a negative reproduction (impression) that can be filled with dental stone for a positive cast.
- Final cast is critical for constructing dentures, crowns, fixed dental prostheses, and restorations.
Impression Trays
- Trays carry impression material to the mouth and support it until set.
- Functions of trays include acting as a carrier and providing support for the set impression.
Types of Impression Trays
- Stock Tray (Prefabricated): Available in plastic disposable or metal materials.
- Custom Tray: Made from a model of the patient with acrylic or other resins for a tailored fit.
- Bite Registration Tray: Records occlusal surfaces of both arches, relates upper and lower casts.
Ideal Requirements of Impression Materials
- Safety: Non-toxic and non-irritant.
- Patient Acceptability: Factors include setting time, taste, and consistency.
- Accuracy: Demands high surface reproducibility and dimensional stability.
- Ease of Use: Requires good mixing properties and handling.
- Cost-Effectiveness: Affordable with a long shelf life to reduce redoing impressions.
- Elastic Properties: Ensures easy removal post-setting.
- Disinfection: Must be easily disinfected without compromising accuracy.
Classification of Impression Materials
- Organized based on the ability of the material to be withdrawn over undercuts.
Non-Elastic Impression Materials
- Rigid with little to no elasticity; ideal for cases without undercuts, primarily for edentulous patients.
- Key types include Impression Plaster, Impression Waxes, Impression Compound, and Zinc Oxide Eugenol.
Impression Plaster
- Usage: Mainly for complete denture impressions.
- Advantages: Rapid setting and cost-effective.
- Disadvantages: Complex technique, hard and brittle, unpleasant taste.
Impression Waxes
- Nature: Thermoplastic material that softens with heat and hardens upon cooling.
- Usage: Primary impressions for dentures, bite registration, and correcting minor voids.
- Advantages: Clean, inexpensive, easy to use.
- Disadvantages: Weakness, lack of accuracy, easily distorted.
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Description
This quiz covers the types and applications of impression materials in dentistry. Learn how these materials are crucial for creating accurate replicas of teeth and oral tissues. Perfect for anyone studying dental materials and their uses in dental practice.
