Prosthetic Dentistry II Quiz: Impression Trays

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Questions and Answers

What is the main difference between stock trays and custom trays?

Stock trays are ready-made and come in specific sizes, while custom trays are fabricated based on a particular patient's cast. (correct)

Stock trays are disposable, while custom trays are reusable after sterilization.

Stock trays are only used for upper dental impressions, while custom trays are for lower dental impressions.

Stock trays are always metallic, while custom trays are always non-metallic.

What factors affect the selection of stock trays?

Color of the impression material, patient's age, type of dental floss used, and arch curvature.

Type of mouth, type of impression material, size of the arch, and form of the arch. (correct)

Patient's occupation, type of toothpaste used, arch curvature, and type of dental mirror used.

Brand of the impression material, type of toothbrush used, size of the tongue, and arch color.

What is the purpose of stock trays?

To make a final impression for dental prosthetics.

To provide extra space for impression material with higher viscosity.

To directly adapt to the cast for maximum accuracy.

To carry impression material to the mouth and support it during polymerization. (correct)

What are custom trays made from?

Metallic or non-metallic materials such as cold cure acrylic resin, hot cure acrylic resin, or light cure acrylic resin. Signup and view all the answers

What is the purpose of spacer and stop trays?

To use a wax spacer to provide extra space for impression material with higher viscosity. Signup and view all the answers

What are the criteria for special tray construction?

Not impinging on movable structures, extending borders beyond the vestibular sulcus, and ensuring sufficient rigidity and thickness. 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 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 the handle of the tray not interfere with lip movements?

To avoid discomfort for the patient Signup and view all the answers

What is the recommended distance from the sulcus to the handle in fabricating a custom tray?

2 cm Signup and view all the answers

Why are disposable trays recommended?

To prevent cross-contamination Signup and view all the answers

What is the function of tray handles in making impressions?

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

What is a function of finger rest?

All of above Signup and view all the answers

What should be done after fabricating a custom tray with spacer and stop?

Clean and disinfect trays before use on patients Signup and view all the answers

What is the purpose of an impression tray in dentistry?

To carry, confine & control the impression material in the patient's mouth Signup and view all the answers

Why should the border extension of an impression tray be 2mm short of the vestibular depth?

To avoid interference with muscle or frenal attachment Signup and view all the answers

What is an important requirement for an impression tray's handle?

It should be angulated to exclude the lips Signup and view all the answers

What is the purpose of classifying impression trays into metallic and non-metallic types?

Based on the material used to fabricate the trays Signup and view all the answers

Why should an impression tray retain its shape throughout the impression procedure?

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

What is a key requirement for the entire border of an impression tray?

It should be smooth and rounded Signup and view all the answers

Study Notes

According to the method of fabrication, there are stock trays and custom trays or special trays for making dental impressions.
Stock trays are ready-made and come in specific sizes, while custom trays are fabricated based on a particular patient's cast.
Stock trays are reusable after sterilization, while custom trays are unique to the patient and discarded.
Stock trays serve to carry impression material to the mouth and support it during polymerization. They are available in different materials and sizes.
Factors affecting selection of stock trays include the type of mouth, type of impression material, size of the arch, and the form of the arch.
Custom trays are made from a cast recovered from primary impression and used to make a final impression. They are more accurate and comfortable for the patient.
Custom trays can be made of metallic or non-metallic materials, such as cold cure acrylic resin, hot cure acrylic resin, or light cure acrylic resin.
The material choice for custom trays depends on various factors such as fabrication time, material properties, and hazardous effects.
Close-fit trays are directly adapted to the cast, while spacer and stop trays use a wax spacer to provide extra space for impression material with higher viscosity.
Criteria for special tray construction include not impinging on movable structures, extending borders beyond the vestibular sulcus, and ensuring sufficient rigidity and thickness.

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Description

Test your knowledge of impression trays in prosthetic dentistry with this quiz. Topics include the definition of dental impressions, the function of impression trays, and the materials used in making impressions.