Deck 14: Dental Ceramics

Question 1

Which properties listed is(are) correct regarding ceramics?

A) Are opaque
B) Are translucent
C) Have low corrosion and wear
D) A and C
E) B and C

Answer 1

B and C

Question 2

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

Answer 2

A, B, and C are all limitations.

Question 3

During firing, what is the process called when the particles of ceramic melt together at their edges?

A) Rheology
B) Sintering
C) Abfraction
D) Condensation

Answer 3

Sintering

Question 4

What is the common cause of failure of a ceramic-alloy bond?

A) Formation of an oxide layer that is too thick
B) Failure within the ceramic layer itself
C) Failure within the alloy casting
D) An inadequate oxide layer

Question 5

The light source is critical for proper color matching because it has a major influence on how color appears to an observer. What is this principle?

A) Reflectance
B) Translucence
C) Metamerism
D) Transmittance

Question 6

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

A) The core ceramic is used for the entire restoration.
B) The high-strength core replaces the alloy substructure.
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 and C are correct.
E) B and C are correct.

Question 7

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

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

Question 8

What 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 9

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

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

Question 10

What is leucite?

A) Crystalline phase that forms under certain conditions within the glassy phase of dental ceramics
B) Oxide layer that forms on the surface of the alloy substructure
C) By-product that forms on the surface of dental porcelain
D) Amorphous non-crystalline phase in dental ceramics

Question 11

Why is the alloy substructure degassed in a ceramic oven during fabrication of a ceramic-alloy restoration?

A) Remove organic impurities from the alloy surface.
B) Promote the formation of an oxide layer on the alloy.
C) Remove hydrogen cyanide gas formed during the metal casting process.
D) A, B, and C are all correct.
E) Only A and B are correct.

Question 12

What is(are) the primary ingredient(s) of dental porcelain?

A) Silica
B) Quartz
C) Feldspar
D) A and B are correct.
E) A and C are correct.

Question 13

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

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

Question 14

The decision to use an all-ceramic restoration is most controversial for which restoration listed below?

A) Anterior crowns
B) Anterior bridges
C) Posterior crowns
D) Posterior bridges

Question 15

What is porcelain composed of?

A) Feldspar
B) Quartz
C) Silica
D) A and B are correct.
E) B and C are correct.

Question 16

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

Question 17

When would a high-fusing type of dental ceramics be used?

A) Fabricate some all-ceramic restorations
B) Make some all-ceramic restorations
C) Fabricate porcelain-jacket crowns
D) Make ceramic-alloy restorations
E) Make denture teeth

Question 18

What is the principal advantage of any all-ceramic crown in contrast to a ceramic-alloy crown?

A) Simpler manufacturing process
B) Superior fracture resistance
C) Excellent esthetics
D) Lower cost

Question 19

Which of the following statement(s) is(are) true of fluxes formed during the fabrication of dental ceramics?

A) Fluxes cause the ceramic to be more opaque.
B) Fluxes require a higher fusing temperature.
C) Fluxes disrupt the crystal lattice.
D) A, B, and C are true statements.
E) A and C are true statements.

Question 20

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

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

Question 21

Which common metallic element(s) occurs in ceramics in combination with oxygen?

A) Silica
B) Zirconium
C) Aluminum
D) A and C are correct.
E) B and C are correct.

Question 22

Which is an advantage of milling a ceramic crown?

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

Question 23

Which material is used intraorally to repair fractured ceramic restorations?

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

Question 24

Ceramic inlays are generally cemented using ____________ cements.

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

Question 25

Which of the following is not true about ceramic restorations?

A) Esthetically superior
B) Easily fixed if broken
C) Few biocompatibility issues
D) Significant wear of the antagonist

Question 26

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 27

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

A) resin-based
B) chemical-cured
C) shade-controlled
D) A, B, and C are all correct.
E) Only A and C are correct.

Question 28

What does leucite do to porcelain?

A) Makes it stronger
B) Makes it lower fusing
C) Makes it more translucent
D) Makes it lower expanding

Question 29

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

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

Question 30

Which statement is true when contrasting ceramic inlays and composite to esthetically restore small posterior lesions?

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

Question 31

Amorphous ceramic phases are stronger and less soluble than crystalline phases. A pure amorphous phase is transparent, like window glass.

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 32

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

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

Question 33

What will a high-flexural-strength ceramic suggest?

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 34

How are glassy porcelains classified?

A) Fusing temperature
B) Sintering temperature
C) Coefficient of thermal expansion
D) A, B, and C are all factors.
E) Only A and B are correct.

Question 35

Which of the following are other techniques used to form ceramic restorations?

A) Casting
B) Stacking
C) Pickling
D) Sintering

Question 36

Which technique(s) is(are) used to form one-step dental restoration?

A) Stacking
B) Machining
C) Condensing
D) Only A and B
E) Only B and C

Question 37

An all-ceramic crown is often composed of a low-strength opaque ceramic core with a bonded veneer of a stronger but translucent glassy or glass-dominated ceramic. Newer designs have only high-strength crystalline or crystalline-dominated ceramics.

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 38

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 39

What is the amount of lightness or darkness of a ceramic restoration called?

A) Hue
B) Color
C) Value
D) Chroma

Question 40

Ceramic veneers are used most often on ______________ teeth.

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

Question 41

Compare and contrast traditional ceramic restorations with machine-milled ceramic restorations. Give advantages and disadvantages of each.

Question 42

Identify the three color factors assessed in teeth, and explain why each is important to esthetics.

Question 43

What is one of the newest applications for dental ceramics?

A) Implant abutments
B) Multi-unit bridges
C) Denture teeth
D) A, B, and C are all new applications for dental ceramics.