INBDE Restorative Dentistry and Dental Materials

Question 1

Which property of dental composite resins is most responsible for post-operative sensitivity?

Accepted Answer

Polymerization shrinkage creating gap formation

Answer

Polymerization shrinkage (1–5% volumetric) creates contraction stress at the bonded margins, leading to gap formation and post-operative sensitivity.

Question 2

Amalgam's strength is primarily derived from which phase?

Accepted Answer

Gamma-1 phase (silver-mercury)

Answer

The gamma-1 phase (Ag2Hg3) is the matrix phase that gives amalgam its strength, while gamma-2 (Sn7-8Hg) is the weakest and most corrosion-prone phase.

Question 3

Dental porcelain is classified as a ceramic primarily because it contains:

Accepted Answer

Inorganic non-metallic crystalline or glass materials

Answer

Ceramics are inorganic, non-metallic materials; dental porcelain is primarily composed of silica, feldspar, and alumina in a glass matrix.

Question 4

The retention of a full-crown preparation is most influenced by:

Accepted Answer

Taper of the axial walls (convergence angle)

Answer

Axial wall taper (convergence angle) is the most critical retention factor; ideally 6–10° total occlusal convergence maximizes both retention and withdrawal path.

Question 5

Glass ionomer cement bonds to tooth structure primarily through:

Accepted Answer

Ionic bonding to calcium in hydroxyapatite

Answer

Glass ionomer cement bonds chemically to tooth structure via ionic interactions between its polyacrylic acid component and calcium and phosphate in hydroxyapatite.

INBDE - Integrated National Board Dental Exam Practice Test

INBDE - Integrated National Board Dental Exam Practice Test

INBDE Restorative Dentistry and Dental Materials