Dental Materials and Equipment Flashcards
7 cards from real NDAEB 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 Equipment flashcards as text
Which luting cement can cause pulpal irritation due to its highly acidic pH during the initial setting reaction?
Answer: Zinc phosphate cement
Zinc phosphate cement has a very low initial pH near 3.5 during mixing, which can irritate the pulp in deep preparations; a liner or base is recommended before placement.
What is the PRIMARY advantage of using resin cement over zinc phosphate cement for cementing all-ceramic crowns?
Answer: It provides superior bond strength and tooth-matched esthetics
Resin cement bonds to both the tooth and the ceramic through adhesive techniques, offering high retention and being tooth-colored so it does not show through translucent all-ceramic restorations.
Calcium hydroxide is most commonly indicated for use as a:
Answer: Direct or indirect pulp capping material
Calcium hydroxide's high pH (around 12) stimulates the formation of reparative dentin, making it the classic material for direct and indirect pulp capping procedures.
Why is zinc phosphate cement mixed using a broad figure-eight motion on a cool glass slab?
Answer: To dissipate the exothermic heat and lengthen working time
The figure-eight motion spreads the mix over a large area of the cooled slab, dissipating the heat produced by the exothermic reaction and prolonging working time.
What is the primary function of a dentin bonding agent applied before placing a composite resin restoration?
Answer: To seal dentin tubules and create a hybrid layer bonding composite to dentin
Dentin bonding agents infiltrate demineralized dentin to form a hybrid layer, sealing tubules and providing a strong micromechanical bond between dentin and composite resin.
Eugenol-containing temporary cements should be AVOIDED when the planned final restoration is:
Answer: A composite resin restoration
Eugenol inhibits the free-radical polymerization of composite resin, preventing it from fully setting; non-eugenol temporary cement must be used when composite is the planned final material.
Which mechanical property describes a dental material's ability to withstand REPEATED cyclic stress without fracturing over time?
Answer: Fatigue resistance
Fatigue resistance is the ability to endure repeated loading and unloading cycles without failure, which is critical for restorations subjected to thousands of chewing cycles daily.