Deck 14: Dental Ceramics

Question 1

Porcelain refers specifically to ceramics composed mainly of:

A) feldspar.
B) quartz.
C) kaolin.
D) A, B, and C.
E) A and C.

Answer 1

A, B, and C.

Question 2

In ceramic-alloy restorations,the alloy substructure is generally less than _____ mm thick in areas that will be covered by the ceramic.

A) 5
B) 2.5
C) 2
D) 0.5
E) 0.1

Answer 2

0.5

Question 3

Dental porcelain is manufactured primarily from:

A) feldspar.
B) silica.
C) alumina.
D) A, B, and C.
E) A and C.

Answer 3

A, B, and C.

Question 4

The failure of a ceramic-alloy bond is commonly due to:

A) an inadequate oxide layer.
B) formation of an oxide layer that is too thick.
C) failure within the ceramic layer itself.
D) failure within the alloy casting.

Question 5

During firing,the particles of ceramic melt together at their edges in a process called:

A) condensation.
B) sintering.
C) abfraction.
D) rheology.

Question 6

The principal advantage of any all-ceramic crown in contrast to a ceramic-alloy crown is:

A) simpler manufacturing process.
B) lower cost.
C) superior fracture resistance.
D) excellent esthetics.

Question 7

The ceramic should have a coefficient of thermal expansion _____ than that of the alloy in most cases.

A) significantly greater
B) slightly greater
C) slightly less
D) significantly less

Question 8

Which of the following statements is(are)true of fluxes used in the fabrication of dental ceramics?

A) Examples of fluxes include sodium carbonate or potassium carbonate.
B) Fluxes disrupt the crystal lattice.
C) Fluxes promote formation of an amorphous glass.
D) A, B, and C are true statements.
E) A and C are true statements.

Question 9

High-fusing types of dental ceramics are used to:

A) fabricate porcelain-jacket crowns.
B) fabricate some all-ceramic restorations.
C) make ceramic-alloy restorations.
D) make some all-ceramic restorations.
E) make denture teeth.

Question 10

Which of the following statements is(are)true of all-ceramic restorations that use a high-strength core ceramic beneath traditional porcelains?

A) The high-strength core replaces the alloy substructure.
B) The core ceramic is used for the entire restoration.
C) CAD-CAM techniques may be used to design and cut the core material out of a block of high-strength starting material.
D) A, B, and C are true statements.
E) A and C are true statements.

Question 11

Which type of ceramic is applied to the ceramic-alloy restoration in order to hide the color of the alloy?

A) Opaque
B) Gingival
C) Incisal
D) Body
E) Glaze

Question 12

The decision to use an all-ceramic restoration is most controversial for:

A) anterior crowns.
B) anterior bridges.
C) posterior crowns.
D) posterior bridges.

Question 13

The fusing temperature of a medium-fusing dental ceramic is _____° C to _____°

A) 1400; 1731
B) 1288; 1371
C) 1093; 1260
D) 871; 1066

Question 14

Which of the following is the most common application of ceramics in dentistry today?

A) Denture teeth
B) Porcelain-jacket restorations
C) Ceramic-alloy restorations
D) All-ceramic restorations

Question 15

Which of the following are limitations of all-ceramic restorations when contrasted with ceramic-alloy restorations?

A) They will fracture in service more often than ceramic-alloy restorations.
B) All-ceramic restorations require the removal of more tooth structure than ceramic-alloy restorations.
C) The fit of many all-ceramic restorations is not as precise as their ceramic-alloy counterparts.
D) A, B, and C are all limitations.
E) A and C and both limitations.

Question 16

Which of the following statements is true regarding the color of ceramics?

A) Hue is the intensity of the color.
B) Value is the basic shade of the color.
C) Chroma is the amount of lightness or darkness.
D) A low chroma indicates grayness.

Question 17

Leucite is a(n):

A) crystalline phase that forms under certain conditions within the glassy phase of dental ceramics.
B) amorphous non-crystalline phase in dental ceramics.
C) by-product that forms on the surface of dental porcelain.
D) oxide layer that forms on the surface of the alloy substructure.

Question 18

The light source is critical for proper matching because it has a major influence on how color appears to an observer,a principle called:

A) reflectance.
B) transmittance.
C) metamerism.
D) translucence.

Question 19

Ceramics:

A) are opaque.
B) are translucent.
C) have low corrosion and wear.
D) A and C.
E) B and C.

Question 20

During fabrication of a ceramic-alloy restoration,the alloy substructure is degassed in a ceramic oven to:

A) remove organic impurities from the alloy surface.
B) remove hydrogen cyanide gas formed during the metal casting process.
C) promote the formation of an oxide layer on the alloy.
D) do A, B, and C.
E) do both A and C.

Question 21

Leucite makes the porcelain:

A) more translucent.
B) stronger.
C) lower-fusing.
D) lower-expanding.

Question 22

The terms ceramic and porcelain are often used interchangeably.Porcelain is a type of ceramic that results when feldspar,silica,and alumina are fired together with fluxes.

A) Statement 1 is correct; statement 2 is correct.
B) Statement 1 is correct; statement 2 is incorrect.
C) Statement 1 is incorrect; statement 2 is correct.
D) Statement 1 is incorrect; statement 2 is incorrect.

Question 23

Glassy porcelains are classified according to their:

A) fusing temperature.
B) sintering temperature.
C) coefficient of thermal expansion.
D) all of the above.
E) only A and B.

Question 24

A common metallic element(s)that occurs in ceramics in combination with oxygen is(are):

A) silicon.
B) zirconium.
C) aluminum.
D) A, B, and C.
E) A and B.

Question 25

At the atomic level,ceramics are composed of metal-_____ ionic bonds.

A) hydrogen
B) oxygen
C) glycerol
D) silica

Question 26

When contrasting ceramic inlays and composite to esthetically restore small posterior lesions:

A) ceramic inlays use a less aggressive tooth preparation.
B) ceramic inlays require more manipulation of materials by the practitioner.
C) composites require more chair time.
D) composites are less customizable in terms of shade, shape, and restoration design.

Question 27

Which material is used intraorally to repair fractured ceramic restorations?

A) Ceramic
B) Resin composite
C) Hybrid ionomer
D) Methyl methacrylate

Question 28

The amount of lightness or darkness of a ceramic restoration is the:

A) color.
B) hue.
C) chroma.
D) value.

Question 29

Ceramics are fired using a technique called:

A) quenching.
B) casting.
C) sintering.
D) pickling.

Question 30

The coefficient of thermal expansion is important when a ceramic is bonded to an alloy because:

A) ceramic offers thermal insulation.
B) it improves restoration hardness.
C) the expansion and contraction must be matched.
D) all of the above.
E) only A and C.

Question 31

Ceramics exhibit extremely _____ compressive strengths and moduli,but relatively _____ tensile strengths and elongation.

A) low; low
B) low; high
C) high; low
D) high; high

Question 32

Veneers are bonded to the tooth using _____ cements and acid-etching techniques.

A) resin-based.
B) shade-controlled.
C) light-activated.
D) A, B, and C.
E) A and C.

Question 33

Techniques used to form the final dental restoration include:

A) stacking.
B) machining.
C) condensing.
D) all of the above.
E) only A and B.

Question 34

Ceramic veneers are used most often on _____ teeth.

A) maxillary anterior
B) maxillary posterior
C) mandibular anterior
D) mandibular posterior

Question 35

A high flexural strength suggests that a ceramic will:

A) better resist fracture.
B) be susceptible to fracture.
C) have a low clinical survival rate.
D) only A and C.
E) only B and C.

Question 36

Ceramic inlays are generally cemented using _____ cements.

A) zinc polycarboxylate
B) zinc phosphate
C) zinc oxide-eugenol
D) resin-based

Question 37

_____ ceramics are the oldest of the dental ceramics and very esthetic,but they are relatively weak.

A) Leucite
B) Amorphous
C) Feldspathic
D) Crystalline

Question 38

Which is an advantage of milling a ceramic crown?

A) Green state is maximized.
B) It is a one-step process.
C) It requires an elastomeric impression.
D) Laboratory turnaround is minimized.