Dental Materials Science Flashcards
7 cards from real CDT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Dental Materials Science flashcards as text
Which sintering process converts partially stabilized zirconia (pre-sintered blanks) into fully dense ceramic for dental restorations?
Answer: High-temperature sintering at approximately 1450–1530°C in a dedicated oven
Zirconia blanks require sintering at approximately 1450–1530°C to achieve full density, strength, and the tetragonal crystal phase transformation.
The addition of palladium to gold alloys in dental use primarily improves:
Answer: Tarnish and corrosion resistance while raising the melting point
Palladium acts as a whitening agent, raises the melting range, and significantly improves tarnish and corrosion resistance in gold alloys.
In the context of complete denture construction, the term 'processing shrinkage' refers to:
Answer: Dimensional reduction of acrylic resin as it polymerizes in the flask
Acrylic resin undergoes volumetric contraction during polymerization (processing shrinkage), which can distort the denture base if not accounted for.
Which test best evaluates the resistance of a ceramic material to crack propagation under stress?
Answer: Fracture toughness (KIC) measurement
Fracture toughness (KIC) quantifies a material's resistance to crack propagation, critical for predicting clinical longevity of ceramic restorations.
Galvanic corrosion in the oral cavity most commonly occurs when:
Answer: Two dissimilar metals in contact are present in an electrolytic environment
Galvanic corrosion arises from the electrochemical potential difference between two dissimilar metals in the electrically conductive saliva electrolyte.
The primary function of a coupling agent (silane) applied to ceramic surfaces before bonding is to:
Answer: Create a chemical bond between the inorganic ceramic surface and organic resin cement
Silane coupling agents contain both ceramic-reactive and resin-reactive groups, creating a chemical bridge between the inorganic ceramic and organic resin cement.
The clinical relevance of the glass transition temperature (Tg) in denture base resins is that below Tg the material:
Answer: Becomes brittle and more susceptible to fracture from impact
Below the glass transition temperature, polymer chains are immobile, making the resin rigid but brittle and prone to fracture under impact loads.