Dental Materials Flashcards
7 cards from real Dental 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 flashcards as text
Zirconia restorations are preferred for posterior crowns primarily because of their:
Answer: Excellent fracture toughness and high strength
Zirconia's transformation toughening mechanism gives it exceptional fracture toughness, making it ideal for posterior load-bearing restorations.
What is the chief disadvantage of using amalgam as a restorative material?
Answer: Lack of adhesion to tooth structure and poor aesthetics
Dental amalgam does not chemically bond to tooth structure and has a silver-grey color that is not aesthetic, requiring retentive cavity preparation.
Which cement is indicated as a luting agent for all-ceramic restorations to maximize aesthetics and bond strength?
Answer: Resin-based luting cement
Resin cements provide the highest bond strength via micromechanical and chemical adhesion and are available in tooth-matched shades that enhance the esthetics of translucent ceramics.
What is the function of a coupling agent (silane) applied to ceramic surfaces before bonding?
Answer: To chemically bond the ceramic to the resin cement
Silane is a bifunctional molecule that bonds to both the silica in the ceramic and the resin cement, creating a chemical link that greatly increases bond strength.
Which type of resin composite is best indicated for Class V cervical restorations due to its flexibility?
Answer: Flowable composite
Flowable composites have lower filler content and higher resin content, giving them a lower modulus of elasticity that allows flexion at the stress-bearing cervical margin.
What is the primary reason dental varnish is applied over a zinc phosphate cement base?
Answer: To prevent the acid from irritating the pulp during initial setting
Zinc phosphate cement is initially acidic during setting, so varnish is applied over the base to protect the pulp from phosphoric acid irritation until the cement fully sets.
Creep in dental amalgam refers to:
Answer: The slow deformation under a sustained load
Creep is the time-dependent plastic deformation of a material under constant stress, which can cause amalgam to flow beyond cavity margins (marginal ditching) over time.