Principles of Tooth Preparation and Margin Design Quiz

What is the primary goal of tooth preparation?

Which of the following is NOT an aim of tooth preparation?

What is the optimum angle of convergence for molars?

What is the correlation between the height and the arc of displacement?

What is the recommended minimal height for molars?

What is the ideal angle of convergence for margin preparation?

What type of margin design is NOT easily visible on the prepared tooth, impression, and die?

What is the consequence of placing the finish line subgingivally on fillings or post and cores?

What is the recommended bevel angle for margin preparation?

What can be a consequence of overtipping the bur when preparing the margin?

What is the recommended height/width ratio for resistance to displacement?

What is the main advantage of supragingival margins for the patient?

What may be misleading on radiographs due to overlapping of filling material and caries lesion?

Tooth Preparation Goals

Primary goal is to create a stable and retentive foundation for restorations, ensuring long-term success.
Not aimed at merely removing decay or damaged tooth structure; holistic tooth preservation is essential.

Angles and Height

Optimum angle of convergence for molars is typically between 5 to 10 degrees.
Height and arc of displacement correlate; greater height results in increased resistance to displacement.
Recommended minimal height for molars is 4-5 mm to maintain structural integrity.

Margin Preparation

Ideal angle of convergence for margin preparation ensures proper seating of restorations and minimizes stress.
Margin designs that are not easily visible include shoulder margins, making assessment during procedures challenging.

Consequences of Margin Placement

Placing the finish line subgingivally can lead to complications in fillings and post-and-core placement, potentially causing plaque accumulation and periodontal issues.
Recommended bevel angle for margin preparation is typically 30 degrees to enhance esthetics and facilitate smooth transitions.

Bur Preparation Techniques

Overtipping the bur while preparing margins can result in uncontrolled removal of tooth structure, impacting the effectiveness of the restoration.

Resistance Ratios

Recommended height/width ratio for resistance to displacement should ideally be at least 1:2 to enhance stability and retention.

Benefits of Supragingival Margins

Main advantage for the patient includes easier cleaning and maintenance, reducing the risk of periodontal disease and enhancing oral hygiene.

Radiographic Considerations

Overlapping of filling material and caries lesions on radiographs can be misleading, complicating diagnosis and treatment planning.

Test your knowledge of tooth preparation principles and margin design concepts in prosthodontics with this quiz. Topics covered include retention and resistance form, angle of convergence, margin types, and more.