Prosthodontics and Occlusion Flashcards

The vertical dimension of rest (VDR) is typically how much greater than the vertical dimension of occlusion (VDO)?

Answer: 2–4 mm

The interocclusal distance (freeway space) between VDR and VDO is typically 2–4 mm, representing the resting position of the mandible where the elevator muscles are in tonic equilibrium.

Pier abutments in fixed prosthodontics are a problem because they:

Answer: Create a Class I lever when the terminal abutments flex differentially

A pier (middle) abutment creates a Class I lever arm; when one terminal abutment is depressed, the pier acts as a fulcrum, placing destructive tipping forces on the other terminal abutment.

A semi-adjustable articulator can replicate:

Answer: Average condylar settings with some adjustability for protrusive and lateral movements

Semi-adjustable articulators accept protrusive records and facebow transfers to approximate condylar guidance, balancing side angles, and incisal guidance for most clinical procedures.

Deflective occlusal contacts (prematurities) in centric relation that shift the mandible to maximum intercuspation are called:

Answer: Centric relation-centric occlusion (CR-CO) discrepancies

CR-CO discrepancy occurs when premature contacts in centric relation force the mandible to shift anteriorly and laterally to reach maximum intercuspation (centric occlusion).

The most common cause of complete denture instability in the mandible is:

Answer: Severe mandibular ridge resorption

Severe mandibular ridge resorption reduces the supporting base area and alveolar height, making it difficult to achieve a stable, retentive mandibular denture.

Which finish line design provides the best marginal seal and esthetics for an all-ceramic crown?

Answer: Deep chamfer or shoulder with rounded internal line angle

A deep chamfer or shoulder (0.8–1.5 mm) with a rounded internal line angle provides adequate ceramic bulk for strength and good marginal fit for all-ceramic restorations.