LO 3

Question 1

What are the three basic forms of physical structures?

Answer 1

Solid, liquid, gas

Question 2

What are the favourable aspects of solids in dental materials?

Answer 2

Shape/volume (build it up), strength and stability

Question 3

What do you need to understand about liquids?

Answer 3

1. Volume but no definite shape
2. Viscosity for different uses

Question 4

Define thixotropic

Answer 4

A characteristic of some gels and liquids that they will flow more readily under mechanical force (mixing, stirring, or shaking)

Question 5

What do you need to know about gasses?

Answer 5

No volume or shape, e.g nitrous oxide, oxygen, etc.

Question 6

Name 2 examples of dental materials that exist in multiple states

Answer 6

1. Plaster or stone- mixed in a liquid and hardens
2. Fluoride foam - liquid and a gas

Question 7

What are the physical properties of dental materials?

Answer 7

Melting/boiling points, density, viscosity, thermal conductivity, thermal expansion

Question 8

Define density

Answer 8

A measure of the weight of a material compared to its volume (brick vs. sponge)

Question 9

What are the mechanical properties of dental materials?

Answer 9

Hardness, stress, resilience, toughness, fatigue, durability

Question 10

What are the chemical considerations of dental materials

Answer 10

Chemical reactions that change one material into something else (corrosion, galvanism)

Question 11

How are dental materials classified?

Answer 11

Preventative, therapeutic, restorative

Question 12

Describe preventative materials with an example

Answer 12

Used to prevent diseases - fluoride pit and fissure sealants

Question 13

Describe therapeutic materials including an example

Answer 13

Used to treat disease (medical bases, topical treatments for periodontal disease

Question 14

How long are temporary restorative materials meant to last?

Answer 14

Days to weeks

Question 15

How long should permanent restorative materials last?

Answer 15

Years - very long lasting

Question 16

How long should intermediate restorative materials last?

Answer 16

Several weeks to months

Question 17

What 4 things do you need to consider when mixing compounds?

Answer 17

1. Mixing time -time to blend to homogeneous
2. Working time - time to work in mouth before initial set
3. Initial set - material can no longer be manipulated
4. Final set - material has reached ultimate state

Question 18

Name the 3 chemical reaction types used to set restoration materials

Answer 18

1. Chemical setting - reaction when catalyst and base are combined
2. Light activated - blue light used to indicate setting process
3. Dual set - slow chemical reaction (increased with blue light)

Question 19

What will affect the outcome of a compound?

Answer 19

1. Correct ratios
2. Temperature
3. Moisture
4. Shelf life

Question 20

What is a shelf life and what impacts it?

Answer 20

Time a material can be stored before becoming unusable

1. Temperature
2. Humidity
3. Packaging
4. Storage
5. Experation dates