Composites And Glass Ionomers

Question 1

What are the main two components of composites?

Answer 1

Organic resin

Inorganic filler

Question 2

What is the function of the resin?

Answer 2

Helps processing and handling. Allows for direct processing

Question 3

What is the function of the filler?

Answer 3

Gives modulus and wear resistance

Question 4

What are the pros and cons of the resin?

Answer 4

Pros: tough and good for processing

Cons: Poor wear resistance

Question 5

What are the pros and cons of the filler?

Answer 5

Pros: Wear resistant and strong

Cons: Brittle and poor processing

Question 6

How does cross-linking make polymer stronger?

Answer 6

Connects multiple polymer chains creating a stronger one unit matrix rather than several individual chains.

Question 7

What are the pros and cons of more and more cross-linking?

Answer 7

Pros: becomes stronger

Cons: shrinkage

Question 8

_________ leads to polymerization, while _________ leads to the cross-linking of polymers.

Answer 8

Methylmethacrylate;

Dimethacrylate

Question 9

T/F: Smaller filler size leads to better wear properties, better polishing, and better mechanical properties.

Answer 9

TRUE

Question 10

_______ _______ bind the filler to the resin matrix.

Answer 10

Coupling agents

Question 11

What causes shrinkage?

Answer 11

Density change during curing. Can lead to stress on tooth.

Question 12

What is a glass-ionomer cement and how is it cured?

Answer 12

Contains acidic polymer and basic glass.

Cured by acid-base reaction

Question 13

What is one of the major benefits of glass-ionomer adhesive?

Answer 13

Releases fluoride

Question 14

Glass-ionomers are _______ based restoratives.

Answer 14

water

Question 15

Do you need a coupling agent with glass-ionomers?

Answer 15

No

Question 16

What is the major difference between sealant and composite resin?

Answer 16

No filler in sealant

Question 17

What can interfere with polymerization on the thin top layer of resins?

Answer 17

Oxygen

Question 18

How are sealants bonded?

Answer 18

Mechanical retention through microtags and macrotags

Question 19

What is the most important aspect of adhesives?

Answer 19

Contain both hydrophilic and hydrophobic qualities.

Question 20

Are adhesives filled?

Answer 20

They are unfilled or lightly filled

Question 21

T/F: Etch is used to remove smear layer from dentin before restoring.

Answer 21

True

Question 22

________ are used to bind restorations of appliances to tooth structure.

Answer 22

Cements

Question 23

Cements have low ________ but good _________ properties.

Answer 23

Viscosity; mechanical

Question 24

For cement mixtures, more powder equals more _______, which leads to a higher _______.

Answer 24

Filler; viscosity

Question 25

What types of cements are used in orthodontics?

Answer 25

Resin based cements.

Question 26

________ are used to protect dentin from the restoration. Often used in deep restorations.

Answer 26

Liners

Question 27

What liner is used in pulp capping?

Answer 27

Calcium hydroxide

Question 28

What is the function of ZOE liners?

Answer 28

Reduce pain. Cannot use under composite

Question 29

_______ are used to provide thermal protection for the pulp and mechanical support for the restoration.

Answer 29

Bases

Question 30

______ ________ is an example of a base.

Answer 30

Glass ionomer

Question 31

What governs the properties of different waxes?

Answer 31

Molecular weight

Question 32

What are the two major classes of impression materials?

Answer 32

Hydrocolloid - water based (alginates & agar-agar) Elastomers - hydrophobic (polysolfides)

Question 33

What are the ideal properties of impression material?

Answer 33

1. Low cost 2. Long shelf life 3. Biocompatible 4. Pleasant to patient 5. Dimensionally stable 6. Good handling properties

Question 34

T/F: Alginates are used for crown and bridge impressions?

Answer 34

False. Not accurate enough.

Question 35

What happens during alginate setting up reaction?

Answer 35

Calcium cross links are made after the retarder allows for enough working time.

Question 36

Advantages and disadvantages of water based alginate?

Answer 36

Pros: easy to work with in mouth Cons: shrinking and expanding

Question 37

Polysiloxanes are _________ impression materials.

Answer 37

Hydrophobic

Question 38

T/F: Polysiloxanes have a much higher dimensional stability than alginate.

Answer 38

True

Question 39

What role do surfactants play in polysiloxanes?

Answer 39

They give them more hydrophilic properties

Question 40

Gypsum is cured with what?

Answer 40

water

Question 41

Explain the dehydration and rehydration of gypsum.

Answer 41

Dehydrated to become powder -> mix with water -> rehydrated to become workable

Question 42

What gives gypsum its strength?

Answer 42

Interlocking of gypsum crystals.

Question 43

T/F: Dental plaster is used for models.

Answer 43

FALSE. Dental STONE

Question 44

T/F: Denture base is normally visible light cured.

Answer 44

True

Question 45

T/F: Provisionals are usually chemically cured.

Answer 45

True

Question 46

What is a major difference between TRIAD and trim/jet?

Answer 46

TRIAD = polymethyl methacrylate Trim/jet = polyethyl methacrylate

Question 47

T/F: Mouthguards use a thermoset polymer.

Answer 47

FALSE. Thermoplastic

Question 48

Properties of mouth guard materials are controlled by a __________.

Answer 48

copolymer