Ceramics and Glass

Question 1

Classification of ceramics by tissue attachment

Answer 1

How they react to the surrounding tissue

Question 2

Type 1 Bioceramics

Answer 2

Inert: do not chemically bond with surrounding tissues
Nonporous:
Fibrous capsule: a layer of protein thickening of a capsule causes failure dependent on material and movement
Movement increases the thickness of the capsule, increasing failure

Question 3

Type II Bioceramics

Answer 3

Bioinert
Porous
Surrounding tissue can grow into the pores of the implant
biological fixation
increased resistance to movement improving the stability of the implant
can withstand higher compressive stress

Question 4

Limitations of Type II

Answer 4

Vascularization
Pore size
movement and snipping of bloodvessels
Necrosis

Question 5

How are type II more stable

Answer 5

Pores hold type II in place, making it more stable mechanically, which makes it move less, reducing fibrous capsule formation

Question 6

Type III

Answer 6

Bioactive response: Bond formation between material and tissue and elicit a specific response
Concerns:
Small changes in composition have dramatic effects on bioactivity

Question 7

Type IV Bioceramics

Answer 7

Resorbable

Question 8

Forming Process of Bioceramics

Answer 8

Ceramics: Powder
Mix with water and an organic binder
Mold shaping (“forming”)
Product: greenware
Raise Temp: Evaporate water and burn binder
Increase temp more: Densify particles (Sintering)
Cool and polish

Question 9

what a phase diagram shows

Answer 9

How solids liquids and gases exist in equilibrium

Question 10

1nuclezation
2.
Grain step

Question 11

Glass

Answer 11

1. heat/melt to Tm
2. Maintain temp to homogenize the liquid
3. quench to room temp
   glass formation easier at higher concentrations of Si02 (slow cooling possible)
   The viscosity of melt increases upon cooling

Question 12

What is quenching

Answer 12

reducing temperature fast enough to prevent crystal formation

Question 13

Liquid Phase sintered cersmic

Answer 13

1. Forming or casting
2. Grains in material (10-40 porosity)
3. heat to T3: Liqud
4. at T2: liquid fills pores
5. Capillary action
   more efficient

Question 14

Solid State sintered ceramic

Answer 14

Heating to the point where porosity but no liquid forms (T4)
atoms move due to the surface energy gradient
pores fill
channels open
crystals become tightly bonded together
pure oxides
slower
high purity
uniform fine-grained

Question 15

Reasons to use solid state over liquid state