Week 8 Flashcards

1
Q

What are 4 biomedical applications of metals outside of dentistry?

A
  1. orthopedic implants
  2. fracture management devices
  3. stents
  4. spinal cage
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are 5 biomedical applications of metals in dentistry?

A
  1. brackets
  2. dental implants
  3. tools
  4. RPD
  5. restorations - amalgam
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Where are metals found in the periodic table?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Any of several solid mineral elements that are malleable under heat or pressure and can conduct heat/electricity

A

metal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are 4 examples of metals?

A
  1. iron
  2. gold
  3. silver
  4. copper
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Why don’t pure metals have practical use in the industry?

A

low properties and expensive fabrication

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

the mix of two or more substances where at least one of them is a metal

A

alloy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What two things make up steel?

A
  1. iron
  2. carbon
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What two things make up amalgam?

A
  1. mercury
  2. silver
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the differences between metals and alloys?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What type of structure do metals have?

A

crystalline

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

True or false: metals are arranged in very compact and orderly patterns

A

true

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the three main arrangement of atoms in metals?

A
  1. cubic body centered
  2. cubic face centered
  3. hexagonal
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the five main methods of metal product manufacture?

A
  1. machining
  2. metal casting
  3. forging
  4. pressing
  5. 3D printing
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What influences final properties of metals?

A

fabrication processes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the 6 post-processing (heat treatment) fabrication methods?

A
  1. annealing
  2. quenching
  3. agin
  4. stress
  5. relieving
  6. tempering
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How are metal parts fabricated?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What 5 characteristics make up the ideal metallic biomaterial?

A
  1. high corrosion resistance
  2. biocompatibility
  3. osseo-integration
  4. high wear resistance
  5. suitable mechanical properties
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is wolf’s law of bone remodelling?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

a result of removal of stress from the bone due to an implant

A

osteopenia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Ostepenia is an example of resorption or remodelling?

A

resorption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Who usually is affected by osteopenia?

A

astronauts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

a biomechanical phenomenon causing adaptive changes in bone strength and stiffness around metallic implants, which potentially lead to implant loosening

A

stress shielding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Describe bone loss in Gruen zones

A

composite = too weak and could break (remove/resorb bone due to low stress)

titanium = just enough stress to both resorb and make bone (ideal substance for implants)

co-cr-mo = too much stress, bone continually added and too stiff

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What are 6 common metallic biomaterials?
26
What is the gold standard in implant materials?
titanium (Ti) and Ti-alloys
27
What are the two characteristics of Ti and Ti-Alloys?
1. light weight (2x lower than stainless steel and Co-Cr alloy) 2. suitable mechanical properties for load-bearing
28
What is commercially pure Ti or cp-Ti?
29
Describe the mechanical properties of cp-Ti and how they change with grades
30
What are the Ti phases?
31
Ti is manufactured via controlled machining which comprises what 3 things?
1. lathing 2. threading 3. milling
32
Why is casting Ti alloys difficult?
1. high melting points (1700 C) 2. Ni absorption
33
Describe the classification of Ti-alloys according to ASTM
34
What three things do Ti alloys (Ti6Al4V) consist of?
35
What are the Ti6AL4V properties?
36
When is an implant osseointegrated?
when virtually no mobility in the bone is clinically detectable
37
How should the interface be between the alloy and the bone of an implant?
direct with no intervening fibrous tissue
38
Bony tissue grows to within _____ A of the implant surface
100
39
Why is Ti alloy one of the most biocompatible materials?
it has excellent corrosion resistance
40
What is the corrosion resistance of a Ti alloy due to?
formation of inert oxide layer
41
In a Ti-alloy implant, where does bone grow?
adjacent to oxide surface
42
What is the main reason for excellent biocompatibility of Ti?
low level of charge transfer
43
The oxide layer is self-healing, what does this mean?
if the surface is scratched it repassivates instantaneously
44
How does the oxide layer form?
titanium spontaneously forms a oxide surface on exposure to air or physiologic saline environment
45
What makes up stainless steel?
46
What is corrosion resistance attributed to?
formation of chromium oxide layer (Cr2O3) **more quantity of Cr, better corrosion resistance
47
The (less/more) quantity of Cr, the better the corrosion resistance
more
48
What is the classification of stainless steel?
49
What are the 4 characteristics of martensitic SS?
50
What are the two characteristics of ferritic SS?
1. manufacturing medical devices 2. handles for instruments and medical guide pins
51
What are 4 characteristics of austenitic SS?
1. excellent cryogenic properties 2. high temperature strength 3. oxidation resistance 4. formability
52
What 4 things does SS 316L consist of?
1. Iron 60-65% 2. Chromium (17-20%) 3. Nickel (12-14%) 4. Small amounts of Mo, Ni, C, P, Si, F
53
What does the L in 316L stand for?
low carbon content (<0.030%)
54
Why is it important to have low carbon content?
for excellent corrosion resistance (prevent carbide accumulation)
55
What 3 things is SS 316L primarily used for?
1. coronary stents 2. orthopedic implants 3. fracture fixation devices
56
What is the drawback of SS 316L?
release of certain metal ions that may lead to some serious disease (Fe, Ni, Cr)
57
What are the four common variations of cobalt based alloys (co-cr alloys)?
58
What has higher corrosion resistance? stainless steel or cobalt-based alloys?
cobalt based alloys b/c they form a Cr2O3 oxide layer
59
Describe the roles of alloying elements
60
What are two issues associated with cobalt-based alloys?
1. stress shielding 2. metal toxicity
61
Co alloys are generally superior to stainless steels in terms of what 3 things?
1. corrosion 2. fatigue 3. wear
62
What remains the most popular metallic implant for joint bearing systems?
Wrought Co-Cr-Mo alloys
63
What is an outstanding property of nitinol?
64
What does nitinol consist of?
65
What are two examples of smart applications?
1. self expanding stents 2. smart brackets
66
True or false: Biocompatibility remains controversial for Ni-Ti
True