NDAEB Dental Materials and Equipment 3

Question 1

Which luting cement can cause pulpal irritation due to its highly acidic pH during the initial setting reaction?

Accepted Answer

Zinc phosphate cement

Answer

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.

Question 2

What is the PRIMARY advantage of using resin cement over zinc phosphate cement for cementing all-ceramic crowns?

Accepted Answer

It provides superior bond strength and tooth-matched esthetics

Answer

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.

Question 3

Calcium hydroxide is most commonly indicated for use as a:

Accepted Answer

Direct or indirect pulp capping material

Answer

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.

Question 4

Why is zinc phosphate cement mixed using a broad figure-eight motion on a cool glass slab?

Accepted Answer

To dissipate the exothermic heat and lengthen working time

Answer

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.

Question 5

What is the primary function of a dentin bonding agent applied before placing a composite resin restoration?

Accepted Answer

To seal dentin tubules and create a hybrid layer bonding composite to dentin

Answer

Dentin bonding agents infiltrate demineralized dentin to form a hybrid layer, sealing tubules and providing a strong micromechanical bond between dentin and composite resin.

(NDAEB) National Dental Assisting Examination Board Practice Test

(NDAEB) National Dental Assisting Examination Board Practice Test

NDAEB Dental Materials and Equipment 3