Substructure for Ceramics Flashcards
7 cards from real CCE practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Substructure for Ceramics flashcards as text
Which metal alloy type offers the highest bond strength with ceramic veneers due to its oxide layer formation?
Answer: Base metal alloy
Base metal alloys form a robust oxide layer that chemically bonds to dental porcelain, providing superior ceramic adhesion.
When designing a metal substructure, the recommended minimum metal thickness for strength without excess bulk is:
Answer: 0.3–0.5 mm
A metal coping thickness of 0.3–0.5 mm provides adequate rigidity to support the overlying ceramic without adding unnecessary bulk.
What purpose does the oxidation (degassing) firing serve in preparing a metal substructure for porcelain?
Answer: It removes surface contaminants and forms an oxide layer
Oxidation firing burns off organic contaminants and creates a controlled oxide layer that promotes chemical bonding with the opaque porcelain.
A connector on a fixed partial denture (FPD) substructure must have a minimum cross-sectional area of approximately:
Answer: 4 mm²
A minimum 4 mm² cross-sectional area for connectors is recommended to resist fracture under functional occlusal loading.
Which design feature of a porcelain-fused-to-metal (PFM) coping helps prevent porcelain fracture at the facial margin?
Answer: Metal collar or labial shoulder chamfer
A metal collar or deep chamfer at the facial margin supports the porcelain edge and prevents chipping by eliminating unsupported ceramic.
Which property is most critical when matching a metal alloy to a specific dental ceramic for a PFM restoration?
Answer: Coefficient of thermal expansion (CTE)
The CTE of the metal and ceramic must be closely matched (metal slightly higher) to prevent residual stress and ceramic fracture during cooling.
What is the primary advantage of a zirconia substructure over a metal substructure for all-ceramic restorations?
Answer: Elimination of a metal-ceramic interface and improved esthetics
Zirconia substructures eliminate the opaque metal coping, allowing superior light transmission and a more natural tooth appearance.