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Questions and Answers
What is an impression tray used for?
What is an impression tray used for?
The impression tray is a device used to carry the impression material into the mouth, maintaining it in position during setting, and supporting it during removal from the mouth and when casting the impression.
What are the two main parts of an impression tray?
What are the two main parts of an impression tray?
An impression tray is typically made up of a body and a handle.
What parts make up the body of an impression tray?
What parts make up the body of an impression tray?
The body of an impression tray consists of a floor and flanges.
The upper impression tray has lingual flanges and the lower impression tray has palatal flanges.
The upper impression tray has lingual flanges and the lower impression tray has palatal flanges.
What is one of the most important requirements for an impression tray?
What is one of the most important requirements for an impression tray?
Impression trays should always be disposable.
Impression trays should always be disposable.
What is the purpose of an impression tray in terms of impression material?
What is the purpose of an impression tray in terms of impression material?
Explain the importance of the flanges of the tray in relation to the functional position of the sulci and frena.
Explain the importance of the flanges of the tray in relation to the functional position of the sulci and frena.
Impression trays should never be modified.
Impression trays should never be modified.
What are the two main categories of impression trays?
What are the two main categories of impression trays?
Describe stock impression trays and their availability.
Describe stock impression trays and their availability.
How does the shape of a stock impression tray vary?
How does the shape of a stock impression tray vary?
Describe the features of the stock impression tray designed for dentulous patients.
Describe the features of the stock impression tray designed for dentulous patients.
Which type of impression tray is considered more suitable for dentulous patients and why?
Which type of impression tray is considered more suitable for dentulous patients and why?
Describe the features of the stock impression tray specifically designed for edentulous patients.
Describe the features of the stock impression tray specifically designed for edentulous patients.
Describe the impression tray required for partially-edentulous patients and its key features.
Describe the impression tray required for partially-edentulous patients and its key features.
What are the different materials used in stock impression trays?
What are the different materials used in stock impression trays?
Stock trays made from plastic are generally reusable.
Stock trays made from plastic are generally reusable.
What is the primary purpose of stock impression trays in the dental procedure?
What is the primary purpose of stock impression trays in the dental procedure?
What is the crucial requirement when selecting the correct stock tray for a patient?
What is the crucial requirement when selecting the correct stock tray for a patient?
What can happen if the wrong impression tray is selected?
What can happen if the wrong impression tray is selected?
What is the potential outcome of using a tray with long flanges during an impression?
What is the potential outcome of using a tray with long flanges during an impression?
Explain what happens when a short impression tray is used.
Explain what happens when a short impression tray is used.
Why do some dentists prefer to modify stock trays?
Why do some dentists prefer to modify stock trays?
What are the common modifications dentists make to stock impression trays?
What are the common modifications dentists make to stock impression trays?
What is the significance of a study cast in dentistry?
What is the significance of a study cast in dentistry?
What is the difference between a study cast and a working cast?
What is the difference between a study cast and a working cast?
How is a study cast made?
How is a study cast made?
Explain the process of making a study cast.
Explain the process of making a study cast.
Flashcards
Impression Tray
Impression Tray
A device used to hold and position impression material in the mouth during setting and removal.
Impression Tray Parts
Impression Tray Parts
Consists of a body (floor and flanges) and a handle. Upper trays have a palatal portion, lower trays have lingual flanges.
Impression Tray Requirements
Impression Tray Requirements
Strong and rigid for accurate impressions, smooth for hygiene; confine material, equal thickness and reach sulci/frena without displacing; mechanical lock or adhesives for material retention, available in various sizes/shapes, and inexpensive.
Stock Trays
Stock Trays
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Stock Tray Materials
Stock Tray Materials
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Study Cast
Study Cast
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Creation of a Study Cast
Creation of a Study Cast
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Study Notes
Impression Trays
- Impression trays are devices used to hold impression material in the mouth.
- They maintain the material's position while it sets and during removal, as well as during the casting process.
- Trays consist of a body and a handle.
- The body comprises a floor and flanges.
- Upper trays have a palatal portion, while lower trays have lingual flanges.
- Impression trays must be strong and rigid to prevent distortion during removal.
Requirements of Impression Trays
- Trays need to be smooth and clean, and sterilizable if not disposable.
- They must confine the impression material and hold it in the right position to cover the whole jaw area.
- The trays must allow for equal thickness of impression material.
- Flanges must reach the sulci and frena without causing displacement.
- Mechanical locking (rim-lock undercuts or perforations) or adhesives are used to secure elastic impression materials.
Stock Trays
- Stock trays are pre-made trays available in various sizes and shapes.
- They are inexpensive and meant for preliminary impressions.
- Sizes and shapes are adjusted to accommodate different arch sizes and types of patients (dentulous, edentulous, or partially edentulous cases).
- Stock trays are available in various materials including nickel silver, stainless steel, aluminum tin, and plastics.
- Plastic stock trays are disposable.
- Incorrect tray selection results in distorted impressions.
Dentulous Patients (teeth present)
- Trays designed for patients with teeth have flat floors, high flanges, and the handle aligns with the floor.
- Perforated or Rim-lock trays are often chosen for these patients.
Edentulous Patients (no teeth)
- Trays for toothless patients have rounded floors and short flanges that accommodate the ridge shape.
- Handles are often L-shaped, enabling border moulding in the labial areas of the impression.
Partially Edentulous Patients (some teeth)
- Trays for these patients have a flat floor and high flanges in the area with remaining teeth, with a rounded floor and short flanges in the toothless areas.
Construction of Primary or Study Cast
- A cast is a positive reproduction of the upper or lower arch tissue captured in an impression.
- The study cast is made from a preliminary impression.
- The working cast is created from the final impression.
- Denture bases or other dental restorations are fabricated using the working cast.
- Plaster of Paris mixes need to be poured in stages to avoid air trapping.
- The casting and finishing processes are often required to complete the cast.
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