DCP- FPD- Impression

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Questions and Answers

What are the key properties of ideal impression materials used in Fixed Prosthodontics?

High cost, easy availability, and quick setting time

Dimensional stability, tear resistance, and ability to reproduce fine details (correct)

Color variety, tastelessness, and high viscosity

Low cost, flexibility, and easy disinfection

Why is it important to add perforations to custom trays for dentate patients?

To increase the rigidity of the tray

To reduce the weight of the tray

To help in mechanical retention of impression material (correct)

To improve the aesthetics of the tray

What are the learning objectives related to impression materials in Fixed Prosthodontics?

Classify impression materials, identify the features of ideal and unacceptable impressions, compare different types of impression trays, list disinfection methods, identify impression techniques, and explain properties of ideal impression materials. (correct)

Discuss the cost of impression materials, compare impression materials with orthodontic materials, and list the side effects of impression materials.

List the names of impression materials, explain the history of impression materials, and discuss the future of impression materials.

Compare impression materials with restorative materials, identify the color of impression materials, and explain the manufacturing process of impression materials.

What are the key terms related to impression materials in Fixed Prosthodontics?

Impression material, impression tray, and dental impression Signup and view all the answers

What are the specifications of a custom tray for dentate patients?

Thickness of tray 2-3 mm (acrylic material) and addition of 2mm diameter perforations Signup and view all the answers

What are the advantages of elastomeric impression materials?

Good dimensional stability, high accuracy, and excellent tear strength Signup and view all the answers

Which characteristic of ideal impression material is related to the material's ability to flow without slumping?

Wettability Signup and view all the answers

What is the primary purpose of using two different materials with different viscosities in full coverage restorations?

To capture fine details and bulk Signup and view all the answers

Which characteristic is NOT considered an ideal impression material characteristic?

High filler content Signup and view all the answers

What is the primary purpose of measuring wettability in impression materials?

To test wetting properties Signup and view all the answers

Which characteristic is critical for addressing troubleshooting in impression making?

Dimensional stability Signup and view all the answers

What is the purpose of using hydrophilic impression materials despite their requirement for good moisture control?

To ensure accurate impressions Signup and view all the answers

What is the purpose of a stopper and wax spacer in dental impression techniques?

To prevent impression material from making intimate contact with teeth and to temporarily fill space during custom tray construction Signup and view all the answers

Why are custom trays preferred over stock trays for multiple teeth restoration?

They are rigid and minimize distortion Signup and view all the answers

What is the advantage of using custom metal trays for dental impressions?

Rigidity and ability to accommodate material Signup and view all the answers

Why is tray adhesive added to the impression tray?

To chemically retain and prevent distortion of the impression material Signup and view all the answers

What is the purpose of capturing preparation stress with a spacer in the impression material?

To minimize distortion of the impression material Signup and view all the answers

What is the significance of pouring elastomeric impression materials within 30 minutes of setting?

To ensure accurate reproduction of oral tissues Signup and view all the answers

Which impression material undergoes cationic polymerization with no by-product formation?

Polyether Signup and view all the answers

What is the main disadvantage of using latex gloves when mixing PVS putties?

They inhibit polymerization of PVS materials Signup and view all the answers

What is the main advantage of polyether over addition silicone?

Hydrophilicity Signup and view all the answers

What is the main reason for difficulties in removal from undercut areas when using addition silicones?

Stiffness Signup and view all the answers

What type of gloves should be used to avoid contamination when handling condensation silicones?

Vinyl gloves Signup and view all the answers

What is the shelf life of condensation silicones?

Limited Signup and view all the answers

What is the working time for addition silicone (PVS) impression materials?

5 minutes Signup and view all the answers

What is the setting time for polysulfide impression materials?

8-14 minutes Signup and view all the answers

What is the required detail reproduction level for putty impression materials?

75 microns Signup and view all the answers

What is the nature of surfactants added to hydrophobic silicones in dental impression materials?

Combat their nature and improve wettability Signup and view all the answers

What is the nature of die stones in reproducing detail in dental impressions?

Required to reproduce detail down to 50 microns Signup and view all the answers

What is the shelf-life limitation of condensation silicone impression materials?

Limited due to its sensitivity to heat and moisture Signup and view all the answers

Study Notes

Dental Impression Materials Overview

Dental impression materials capture details with low viscosity and must be removed from the patient's mouth without distortion
Surfactants are added to hydrophobic silicones to combat their nature and improve wettability
Elastomeric impression materials are required to record detail down to 20 microns
Die stones are required to reproduce detail down to 50 microns
Putty captures details down to 75 microns
Working time for elastomeric impression materials is approximately 2 minutes, and setting time is 2-6 minutes
Elastomeric impression materials have three types of viscosity: low, medium, and heavy
Polysulfide materials have a thixotropic property and are supplied as two pastes: base and catalyst
Polysulfide materials have a working time of 5-7 minutes and a setting time of 8-14 minutes
Condensation silicone undergoes a condensation reaction that produces ethyl alcohol as a by-product, causing high shrinkage
Addition silicone, also known as polyvinylsiloxanes (PVS), have a working time of 5 minutes and a setting time of 10-12 minutes
Shelf-life of condensation silicone is limited due to its sensitivity to heat and moisture

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Description

Test your knowledge of dental impression materials with this overview quiz. Explore topics such as elastomeric materials, die stones, putty, polysulfide materials, condensation silicone, and addition silicone. Gain insight into working time, setting time, viscosity, and other essential characteristics of these materials.