AGD Dental Materials and Biomaterials 3

Question 1

Which optical property of ceramics is most critical for matching the appearance of natural tooth enamel?

Accepted Answer

Translucency

Answer

Natural enamel is semi-translucent, so ceramic translucency is essential for an esthetic match, allowing light to pass through similarly.

Question 2

The coefficient of thermal expansion (CTE) mismatch between a ceramic and its underlying metal substructure can cause:

Accepted Answer

Ceramic fracture or delamination

Answer

CTE mismatch creates thermal stress during firing and intraoral temperature changes, leading to ceramic fracture or delamination from the metal.

Question 3

Which mechanism primarily accounts for the superior strength of zirconia compared to other dental ceramics?

Accepted Answer

Transformation toughening

Answer

Zirconia undergoes stress-induced tetragonal-to-monoclinic phase transformation, absorbing crack energy and dramatically increasing fracture toughness.

Question 4

Galvanic corrosion in the oral cavity is most likely to occur when:

Accepted Answer

Dissimilar metals are in contact with saliva

Answer

Galvanic corrosion occurs when dissimilar metals with different electrode potentials are in electrical contact through an electrolyte like saliva.

Question 5

Which component of dental porcelain gives it its characteristic glass-like quality?

Accepted Answer

Silica-based glass matrix

Answer

The silica-based glass matrix provides translucency and the glass-like optical and physical properties characteristic of dental porcelain.

(AGD) Academy of General Dentistry Certification Practice Test

(AGD) Academy of General Dentistry Certification Practice Test

AGD Dental Materials and Biomaterials 3