Dental Cast and Die Preparation Quiz

Master Cast and Die Requirements

• A Master Cast should accurately reproduce the prepared teeth and surrounding tissues.
• The unprepared teeth on the Master Cast should be free of wax, debris, and other obstructions.
• The Master Die must have a rounded, smooth, and continuous cervical area to help establish the correct cervical contour of the restoration.

Master Die Requirements

• The Master Die should provide adequate access to the margin for finishing and inspection.
• The Master Die is important for accurate Marginal adaptation and fit of the final restoration.

Definitive Cast Requirements

• The Definitive Cast should accurately reproduce the unprepared teeth and surrounding tissues in high detail.
• The Definitive Cast must allow for precise registration of the occlusal surfaces of the unprepared teeth.

Stone and Plaster Properties

• Stone is stronger than plaster because of its lower water-to-powder ratio and higher compressive strength.
• Type III stone (dental stone) is best for polyether or polyvinyl impression materials.
• The main difference between Type IV and Type V stone is their compressive strength, with Type V having a higher compressive strength.

Mixing and Applications

• Vacuum mixing is required for Type IV and Type V stone to minimize air bubbles and maximize strength.
• Type I plaster is used for mounting casts in the laboratory.
• The main reason for the weakness of plaster compared to stone is its higher water-to-powder ratio and lower compressive strength.
• Type IV High-strength, Low-expansion stone is primarily used for fabricating dentures and other restorations that require high accuracy and detail.
• The main advantage of stone over plaster is its more consistent and predictable mixing properties.