Biomechanics and Biomaterials

Question 1

A good wetting material will have what contact angle?

Answer 1

Low contact angle; approaching 0

Question 2

A poor wetting material will have what contact angle?

Answer 2

High contact angle; approaching 180

Question 3

Are good wetting agents typically hydrophilic or hydrophobic?

Answer 3

Hydrophilic

Question 4

Hydrophilic chemicals will wet what kind of surfaces?

Answer 4

Hydrophilic

Question 5

What are four important aspects of surface wetting?

Answer 5

Important anytime two different materials come into contact; important in impression materials; important in adhesives; and important in bacterial adhesion

Question 6

What is primary bonding affected by?

Answer 6

Generally affected by chemical and electro chemical reactions

Question 7

What is secondary bonding affected by?

Answer 7

Generally affected by processes such as adsorption (onto) and absorption (into)

Question 8

Chemical properties of a material are those that involve changes in what?

Answer 8

The primary and secondary bonding of the material

Question 9

What is corrosion?

Answer 9

The spontaneous destructive oxidation of metals

Question 10

What metals do not corrode?

Answer 10

Gold, platinum, and palladium

Question 11

What does active metal corrosion lead to?

Answer 11

Destruction (Gamma 2)

Question 12

What does passive metal corrosion lead to?

Answer 12

Produces a film that prevents further corrosion (Titanium implants)

Question 13

In active electrochemical corrosion what is the anode?

Answer 13

The corroding metal

Question 14

In active electrochemical corrosion what is the cathode?

Answer 14

A different metal (passive-supplied electrons to solution)

Question 15

What are the four types of corrosion?

Answer 15

Galvanic, structure selective, crevice, stress

Question 16

How does the chemical dissolution of ceramics happen?

Answer 16

Normally occurs through dissolution of oxides created by hydrogen bonding effects of water in local areas of high acidity

Question 17

What are the two ways that polymers are affected?

Answer 17

Absorption of water into polymers (secondary bonds), and hydrolytic degradation and release of components (primary bonds)

Question 18

When polymers absorb water what is the physical affect?

Answer 18

Dimensional change

Question 19

What are the four major material properties?

Answer 19

Physical, chemical, biological, and mechanical

Question 20

Biologic properties are interrelated with what two things?

Answer 20

Degradation properties, and polymerization process or processing

Question 21

What do the mechanical properties of a material describe?

Answer 21

How a material responds to loads (forces)

Question 22

What are the three single dimension forces?

Answer 22

Compression, tension, and shear

Question 23

What are the three combination forces?

Answer 23

Torsion, flexion, and diametral compression

Question 24

What is resilience?

Answer 24

The amount of force that can be applied before deformation occurs

Question 25

What is toughness?

Answer 25

The amount of force that can be applied before failure or fracture occurs

Question 26

Hardness is a relative measure of what?

Answer 26

Plastic deformation

Question 27

Fracture toughness measures what?

Answer 27

A materials resistance to crack propagation

Question 28

What is creep?

Answer 28

(Strain relaxation); deformation over time in response to low constant stress

Question 29

What is stress relaxation?

Answer 29

Deformation over time in response to low constant strain

Question 30

What are the normal biting forces?

Answer 30

150-550N (35-125lbs)

Question 31

What are max biting forces?

Answer 31

200-2440N (45-550lbs)

Question 32

What is the molar biting force?

Answer 32

500N