Dental Materials and Application Flashcards
7 cards from real AGD 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 and Application flashcards as text
The modulus of elasticity of a restorative material is clinically important because it describes:
Answer: The stiffness of the material under load
The modulus of elasticity (Young's modulus) quantifies stiffness — a high modulus means the material resists elastic deformation, which is critical for load-bearing restorations.
When using a total-etch adhesive technique, what is the critical risk of over-drying the dentin after acid etching?
Answer: Collagen fiber collapse prevents adhesive infiltration and reduces bond strength
Over-drying demineralized dentin causes collagen network collapse, blocking adhesive monomer infiltration and dramatically reducing dentin bond strength.
Which type of zirconia is used in monolithic posterior crowns and valued for its high strength?
Answer: Yttria-stabilized tetragonal zirconia polycrystal (Y-TZP)
Y-TZP zirconia has flexural strength of 900–1200 MPa due to transformation toughening, making it the strongest ceramic for monolithic posterior crowns.
What is the purpose of the oxygen inhibition layer that forms on the surface of light-cured composites?
Answer: It allows chemical bonding to the next increment of composite
The oxygen-inhibited layer contains unreacted monomers that allow subsequent increments or surface sealers to chemically bond, ensuring interlaminar adhesion.
A gold alloy classified as Type IV (extra hard) would most appropriately be used for:
Answer: Thin-gauge clasps for removable partial dentures and long-span bridges
Type IV gold alloys have the highest hardness and yield strength, making them suitable for thin sections under high stress such as clasps and long-span bridge frameworks.
Which factor most significantly affects the depth of cure of a composite resin?
Answer: The shade and translucency of the composite
Darker and more opaque composite shades scatter and absorb light more readily, limiting depth of cure compared to lighter, more translucent shades.
Which surface treatment is recommended before bonding a feldspathic porcelain veneer to improve resin bond strength?
Answer: Hydrofluoric acid etching followed by silane application
Hydrofluoric acid (9.5% for 20 seconds) creates microretentive surface irregularities in feldspathic porcelain, and silane coupling agent then promotes chemical bonding to resin.