Dental Materials: Impression Materials Overview

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Questions and Answers

What is the primary purpose of impression materials in dentistry?

To treat gum disease

To make an accurate replica of teeth and oral tissues (correct)

To improve oral hygiene

To whiten the teeth

What type of reproduction do impression materials create?

Written reproduction

Positive reproduction

Digital reproduction

Negative reproduction (correct)

Which of the following types of trays is custom-made for a patient?

Custom tray (correct)

Disposable tray

Bite registration tray

Stock tray

What form do some impression materials take before being used?

Powders mixed with water or pastes Signup and view all the answers

What is one of the main functions of impression trays?

To carry and support the impression material Signup and view all the answers

What type of impression tray is typically prefabricated?

Stock tray Signup and view all the answers

What happens after the impression material has set?

It is removed from the mouth with the tray Signup and view all the answers

What are custom trays made from?

Acrylic or other resin based on a patient model Signup and view all the answers

What is the primary use of 3-bite registration trays?

To record the occlusal surfaces of both arches Signup and view all the answers

Which of the following is NOT an ideal requirement for an impression material?

Rapid curing Signup and view all the answers

What type of impression materials are characterized by being rigid with little or no elasticity?

Non-Elastic Impression Materials Signup and view all the answers

What is a common disadvantage of impression plaster?

Unpleasant taste Signup and view all the answers

Which of the following is an advantage of impression waxes?

Clean and easy to use Signup and view all the answers

Impression compounds are primarily used for which group of patients?

Edentulous patients Signup and view all the answers

What is a key property of impression materials that allows easy removal from the mouth?

Elastic properties Signup and view all the answers

What kind of impression materials soften on heating and harden upon cooling?

Thermoplastic materials Signup and view all the answers

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.