Prosthodontic & Orthodontic Appliance Fabrication Flashcards

A patient presents with a severely resorbed mandibular ridge. Which denture base design modification can improve retention by extending into the pterygomandibular space?

Answer: Retromylohyoid extension

Extending the denture base into the retromylohyoid space (distolingual extension) takes advantage of the anatomical undercut in this region to improve retention on resorbed ridges.

In the lost-wax casting process for a PFM coping, which step immediately follows investing the wax pattern and allows the investment to set?

Answer: Burnout in the oven

After the investment sets (bench sets), the ring is placed in a burnout oven to eliminate the wax pattern and preheat the mold cavity prior to casting.

What is the primary function of an indirect retainer in a removable partial denture design?

Answer: To prevent the distal extension base from rotating away from the tissue

Indirect retainers are placed anterior to the fulcrum line to counteract rotational displacement (lifting) of the distal extension base away from the supporting tissues.

During complete denture fabrication, which occlusal scheme is most commonly recommended for edentulous patients to maximize stability during function?

Answer: Bilateral balanced occlusion

Bilateral balanced occlusion provides simultaneous posterior contact on both sides in all excursive movements, minimizing tipping forces and maximizing denture stability.

A Herbst appliance used in orthodontics is classified as which type of functional appliance?

Answer: Fixed functional appliance

The Herbst appliance is a fixed functional appliance cemented or banded to the teeth that continuously positions the mandible forward to stimulate condylar growth and correct Class II malocclusions.

When fabricating an implant-supported prosthesis, what is the purpose of a verification jig (fit checker)?

Answer: To confirm passive fit of the framework across multiple implants before processing

A verification jig confirms that the metal framework seats passively on all implants simultaneously without introducing stress at the implant-bone interface.

Which type of pontic design is most hygienic and easiest to clean, making it ideal for long-span bridges in posterior regions?

Answer: Sanitary (hygienic) pontic

The sanitary (hygienic) pontic has a convex tissue surface that does not contact the ridge, allowing easy cleaning underneath and reducing plaque accumulation.