Ceramics

Question 1

What is added to the frit to produce various shades of ceramic?

Answer 1

Pigments

Question 2

What are pigments for producing various shades for ceramics?

Answer 2

Metallic oxides:
Titanium oxide = yellow-brown
Manganese oxide = lavender
Iron oxide = brown
Cobalt oxide = blue
Copper/chromium oxide = green
Nickel oxide = brown
Lanthanide oxides = fluorescence

Question 3

What 2 phases does feldspathic dental porcelain consist of after manufacture?

Answer 3

Vitreous (glass) phase

Crystalline (mineral/leucite) phase

Question 4

T/F Crystalline (mineral/leucite) has high thermal expansion?

Answer 4

True

Question 5

What controls the CTE of procelain and contributes to its strength?

Answer 5

Crystalline (mineral/leucine) 10-20% content

Question 6

What is sintering?

Answer 6

When heated under vacuum, the porcelain particles join together by flow on contact as a result of surface energy

Question 7

What is the first firing of porcelain called?

Answer 7

Biscuit bake

Question 8

Why would a fracture thru the oxide layer occur?

Answer 8

Base metals commonly fracture here if layer is too thick

Question 9

Why would there be a failure dependent on proper bonding of PFM?

Answer 9

Highest strength ceramic-metal specimens fracture in the porcelain

Question 10

Where are the three areas of fracture possible with PFMs?

Answer 10

At the metal-metal oxide layer. Within the oxide layer, and within the porcelain itself

Question 11

What is the compatible CTE of ceramic and metal?

Answer 11

Metal CTE should be slightly higher than ceramic to put ceramic in compression where it is stronger