Dental Impression Trays Quiz

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Questions and Answers

What is the purpose of an impression tray in dentistry?

To provide support for dental implants

To carry, confine & control the impression material in the patient's mouth (correct)

To simulate the finished denture outside the mouth

To shape the teeth and soft tissues in the mouth

What are the requirements of an impression tray?

It should retain its shape throughout the impression procedure and while pouring stone on the impression (correct)

It should extend 2mm beyond the vestibular depth with interference with muscle or frenal attachment

It should be flexible and thin to easily adapt to the patient's mouth

It should be made of a material that dissolves after taking the impression

How should the border extension of an impression tray be positioned?

At the same level as the vestibular depth to ensure maximum coverage

2mm short of the vestibular depth with no interference with muscle or frenal attachment (correct)

1mm short of the vestibular depth to avoid overextension

1cm beyond the vestibular depth for extra support

Which material can be used to fabricate metallic trays?

Stainless steel Signup and view all the answers

What type of trays can be classified as non-metallic?

Plastic trays and acrylic resin trays Signup and view all the answers

What is the function of the spacer in the custom tray?

To properly position the tray during border molding Signup and view all the answers

What is the function of the handle in the custom tray?

Supports the lip while making impression Signup and view all the answers

What is the purpose of applying a separating medium on the cast?

To prevent acrylic resin from sticking to the cast Signup and view all the answers

Why should disposable trays be recommended?

To prevent cross-contamination Signup and view all the answers

What is the purpose of fabricating two posterior handles for mandibular trays?

As finger rests to stabilize tray in mouth Signup and view all the answers

What type of impression material is suitable for close-fit trays?

Impression materials of low viscosity Signup and view all the answers

What is the primary purpose of stock trays?

To make primary impressions Signup and view all the answers

What type of custom tray uses wax spacer to provide space for impression material?

Tray with spacer and stops Signup and view all the answers

Which factor affects the selection of stock trays?

Size of the arch Signup and view all the answers

What are the materials used for fabricating custom trays?

Shellac base plate, impression compound, and cold, hot or light cure acrylic resin Signup and view all the answers

Study Notes

Method of fabrication of trays: Stock trays (full arch, sectional, quadrant), Custom trays or Special trays
According to the presence or absence of teeth: Edentulous trays (rounded cross-section), Dentulous trays (square cross-section)
Stock trays: Reusable, comes in specific sizes, used to make primary impression, materials include Al, Tin, Brass or Plastic
Factors affecting selection of stock tray: Type of impression material, size of the arch, form of the arch, and coverage of anatomical landmarks
Custom trays: Fabricated on a patient's cast, unique to the patient, used for making final impression, materials include shellac base plate, impression compound, and cold, hot or light cure acrylic resin
Factors affecting selection of custom tray: Materials used, compatibility with impression material, and accuracy of fit
Types of custom trays: Close-fit tray, tray with spacer and stops
Close-fit tray: Adapted directly onto the cast without wax spacer, used with impression materials of low viscosity
Tray with spacer and stops: Uses wax spacer to provide space for impression material, used with impression materials of high viscosity
Advantages of special trays: More accurate impression, even thickness of impression material, easier fabrication, better retention, and less bulky.

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Description

Test your knowledge about dental impression trays and their usage in prosthetic dentistry. Learn about the definition of dental impressions and the purpose of impression trays.