DDS Prosthodontics and Restorative Dentistry 2

Question 1

Porcelain-fused-to-metal (PFM) crowns most commonly fracture at which location?

Accepted Answer

Within the occlusal porcelain over functional contacts

Answer

Porcelain fractures most frequently in the occlusal porcelain in areas bearing functional load, as ceramic is brittle and has low tensile strength under repeated occlusal stress.

Question 2

A ferrule effect in crown preparation refers to:

Accepted Answer

Encirclement of sound tooth structure above the cement margin by the crown walls

Answer

The ferrule is a band of sound coronal tooth structure between the preparation finish line and the core, encircled by the crown, which provides anti-fracture resistance to root stress.

Question 3

In dental implant terminology, osseointegration is defined as:

Accepted Answer

Direct structural and functional contact between living bone and the implant surface at the light microscopic level

Answer

Osseointegration (Brånemark's definition) is a direct bone-to-implant contact at the light microscopic level without any intervening fibrous tissue layer.

Question 4

The occlusal scheme most commonly recommended for complete dentures is:

Accepted Answer

Lingualized occlusion or bilateral balanced occlusion

Answer

Bilateral balanced occlusion (contacts on both sides in all excursive movements) or lingualized occlusion is recommended for complete dentures to stabilize the denture base and prevent tipping.

Question 5

The smear layer created during cavity preparation:

Accepted Answer

Can be modified or removed depending on the bonding system (total-etch vs. self-etch)

Answer

Total-etch systems remove the smear layer with phosphoric acid before priming, while self-etch systems incorporate and modify (but don't remove) the smear layer during bonding.

DDS - Doctor of Dental Surgery Practice Test

DDS - Doctor of Dental Surgery Practice Test

DDS Prosthodontics and Restorative Dentistry 2