Questions and Answers
What is a Class III cavity?
Which approach is preferred for a Class III cavity for aesthetic reasons?
What is the depth of a Class III cavity outline form mesially and distally?
2.0 mm
What is the depth of a Class III cavity outline form incisal gingivally?
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Where are Class III cavities located?
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Radiographic Class III cavities can only be incipient.
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Which of the following are types of approaches for Class III cavities?
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What are the types of preparation designs for Class III cavities?
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What type of acid is used in acid etching?
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What does retention form in cavity preparation prevent?
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What is removed when toilet the cavity?
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What is the angle of the bur used for cavity preparation?
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The preferred approach for Class III cavities is the ______ approach.
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Which type of preparation is conservative in nature?
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Study Notes
Class III Cavity Preparations Overview
- Class III cavities affect the anterior interproximal areas, often leading to smooth surface lesions.
- Radiographically, Class III cavities can be classified as either incipient or cavitated.
Preparation Techniques
- Facial Approach: Suitable when the cavity is primarily facial or if replacing an existing facial restoration. Less preferred due to potential damage to facial enamel.
- Lingual Approach: Preferred for aesthetic reasons, helps in preserving facial enamel and minimizes visibility of stains.
Outline Form Specifications
- Depth: 2.0 mm mesiodistally; up to 3 mm incisal-gingivally.
- Shape: Moon-shaped outline with rounded internal and external angles.
- Beveling: Long bevel at the cavosurface angle using a diamond bur is essential.
Cavity Preparation Designs
- Conventional Preparation: Similar to amalgam; characterized by 90-degree cavosurface margins, less outline extensions.
- Beveled Conventional Preparation: Features angled enamel margins, ideal for larger restorations and replacing existing conventional restorations.
- Modified Conservative Preparation: More conservative; relies on micro-mechanical bonding for retention, suitable for smaller lesions.
Retention and Resistance Forms
- Retention Form: Achieved through acid etching, which increases bonding surface area, with angled bevels only needed in large preparations.
- Resistance Form: Ensures the preparatory design prevents dislodgment during restoration.
Convenience and Finishing
- Convenience Form: The smallest composite instrument should easily fit without binding to allow proper placement of matrix strips.
- Finishing Walls: Involves smoothing all cavity walls, removing loose enamel. Utilizes a low-speed handpiece along with hand instruments.
Additional Techniques
- Matrix Strip: A plastic strip used to shape and hold restorative materials, essential for mesial or distal restorations.
- Toilet the Cavity: Involves cleaning debris, drying the cavity, and conducting a final inspection prior to restorative material placement.
Decay Removal
- Use a slow-speed handpiece to gently remove remaining decay, employing light suction motion for precision. Pulp protection may be necessary based on dentin preservation.
Technique Considerations
- Preparation measurements focus primarily on ensuring adequate depth without overly encroaching on the incisal angle.
- The angle of the bur is maintained at 45 degrees to the enamel surface for optimal cutting efficiency.
Summary of Best Practices
- Preference for the lingual approach balances aesthetics and tooth structure preservation.
- Proper techniques in cavity preparation, such as ensuring rounded angles, appropriate depth, and finishing techniques, are crucial in successful Class III restorations.
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Description
This quiz focuses on the essential terminology and definitions related to Class III cavity preparation. Students will learn about interproximal cavities, facial approaches, and the specific outline forms required for effective restorative practices. Perfect for dental students looking to enhance their understanding of cavity preparations.
