NDEB - National Dental Examining Board Restorative Dentistry and Materials Questions and Answers

Question 1

A dentist is restoring a deep Class I occlusal preparation in a mandibular molar using a bulk-fill composite resin.
Which factor associated with the cavity's geometry creates the highest polymerization shrinkage stress?

Accepted Answer

The high ratio of bonded to unbonded surfaces

Answer

Proximity of the preparation to the dental pulp

Answer

The use of a high-intensity LED curing light

Answer

The thickness of the adhesive layer applied

Question 2

When cementing a lithium disilicate crown, which of the following is the mandatory surface treatment for the intaglio surface of the restoration to achieve a strong adhesive bond with a resin cement?

Accepted Answer

Etching with 5% hydrofluoric acid

Answer

Sandblasting with 50-micron aluminum oxide

Answer

Etching with 37% phosphoric acid

Answer

Applying a metal/zirconia primer

Question 3

Which of the following components was significantly increased in modern high-copper dental amalgams with the primary goal of eliminating the corrosion-prone Gamma-2 (γ2) phase?

Accepted Answer

Copper (Cu)

Answer

Zinc (Zn)

Answer

Silver (Ag)

Answer

Tin (Sn)

Question 4

A clinician is using a total-etch (etch-and-rinse) adhesive system for a Class II composite restoration. What is the primary function of the phosphoric acid etching step on dentin?

Accepted Answer

To remove the smear layer and demineralize the intertubular dentin.

Answer

To modify and incorporate the smear layer into the hybrid layer.

Answer

To chemically bond with the calcium in hydroxyapatite.

Answer

To disinfect the dentin surface before bonding.

Question 5

An 8-year-old patient with high caries risk requires a restoration on the facial surface of a partially erupted maxillary first molar where moisture control is challenging. Which material offers the most significant therapeutic and practical advantages in this scenario?

Accepted Answer

Conventional glass ionomer cement

Answer

Packable composite resin

Answer

Dental amalgam

Answer

Flowable composite resin

Question 6

Which of the following restorative materials exhibits a coefficient of thermal expansion (CTE) that is most dissimilar to that of natural tooth structure, posing the greatest risk of percolation and marginal gap formation?

Accepted Answer

Unfilled acrylic resin

Answer

Dental amalgam

Answer

Microhybrid composite resin

Answer

Feldspathic porcelain

A dentist is restoring a deep Class I occlusal preparation in a mandibular molar using a bulk-fill composite resin.Which factor associated with the cavity's geometry creates the highest polymerization shrinkage stress?

A dentist is restoring a deep Class I occlusal preparation in a mandibular molar using a bulk-fill composite resin.
Which factor associated with the cavity's geometry creates the highest polymerization shrinkage stress?