ceramics I- porcelain QUESTIONS ONLY

lecture given 4/30/2026

Decreasing crystal size and increasing crystal content of ceramic?:

A. Increases fracture resistance.

B. Decreases fracture resistance.

C. Increases micro-cracks.

A. Increases fracture resistance.

Generally as the particle size of ceramic and porcelain materials decrease:

A. Mechanical properties increase.

B. Mechanical properties decrease.

C. Mechanical properties do not change.

A. Mechanical properties increase.

Polishing may produce a surface finish just as smooth as glazing:

A. True.

B. False.

A. True.

Surface damage and increased roughness of the porcelain that may occur after occlusal adjustment causes:

A. Increased wear of the opposing dentition.

B. Decreased stress resistance.

C. A and B.

C. A and B.

External Colorants or Stains last:

A. The lifetime of a restoration.

B. About 2 - 4 years.

C. Must be re-applied at every recall visit.

B. About 2 - 4 years.

Wear of the opposing dentition by a ceramic restoration is mostly dependent on:

A. Surface finish and crystal/particle size .

B. Hardness value only.

C. Chemical composition .

A. Surface finish and crystal/particle size .

Glazing of the porcelain can improve flexural strength by:

A. Creating compressive stresses on the surface.

B. Creating tensile stresses on the surface.

C. Creating shear stresses on the surface.

A. Creating compressive stresses on the surface.

When polishing materials you should:

A. Use maximum speed and force.

B. Use maximum speed and a low force.

C. Use low speed and a low force.

C. Use low speed and a low force.

Restorations should always be polished before any other procedure such as glazing or glazing and staining:

A. True.

B. False.

A. True.

A lab changes the type of metal they use with their original porcelain. After you cement the crowns for your last 5 patients the porcelain cracks. This is most likely due to:

A. All the patients chew on bones.

B. The thermal expansion coefficients are mismatched.

C. You polished the porcelain too much.

B. The thermal expansion coefficients are mismatched.