Prosthetics & Dentures Flashcards

What is the most important design consideration to prevent a lower RPD from rotating around its axis?

Answer: Adequate rests anterior and posterior to the saddle (including indirect retainers)

Indirect retainers placed on the opposite side of the fulcrum line (anterior to posterior saddles) resist rotational movement, preventing the distal saddle from lifting during function.

What is the most common material used for the denture base in a standard NHS complete denture?

Answer: Heat-cured polymethyl methacrylate (PMMA) acrylic

Heat-cured PMMA is the standard denture base material in NHS prosthodontics due to its processing accuracy, strength, repairability, and compatibility with mucosal tissues.

What clinical finding would lead you to suspect a mid-palatal torus is causing problems with upper denture construction?

Answer: Prominent bony mass in the mid-palate causing poor retention due to rocking

A mid-palatal torus creates a bony fulcrum under the denture, causing rocking instability and poor retention; it may require surgical removal or careful relief in the denture base.

When assessing a patient's existing dentures prior to replacement, which feature is most important to preserve in the new dentures?

Answer: The adapted neutral zone (polished surface form)

The polished surface form that the patient has adapted to represents the neutral zone; preserving this in the new denture reduces the adaptation time and improves comfort and stability.

What is the difference between a tooth-supported and a tooth-mucosa-supported RPD?

Answer: Tooth-supported has rests on both sides of each saddle; tooth-mucosa-supported has free-end saddles with mucosa bearing load distally

In tooth-supported RPDs, all saddles are bounded by rests; tooth-mucosa-supported dentures have free-end saddles where the distal load is borne by the ridge mucosa, requiring different design considerations.

What is the purpose of a facebow record in complete denture prosthodontics?

Answer: Transfer the spatial relationship of the maxillary arch to the hinge axis of the temporomandibular joint to the articulator

A facebow records the relationship between the upper arch and the transverse hinge axis of the TMJ, allowing the articulator to replicate the arc of closure and condylar movements accurately.