Dental Materials Polymers

Front 1

What is a oligomer?

Back 1

A short polymer that is composed of 2, 3, or 4 -mer units.

Front 2

What is a copolymer?

Back 2

The joining of two or more monomer units.

Front 3

What is the polymerization process? (Summary)

Back 3

The conversion of low-molecular weight monomers to high-molecular weight compounds called polymers.

Front 4

In the polymerization process, what is the initiator?

Back 4

An organic peroxide. (benzoyl peroxide)

Front 5

How does the polymerization process work?

Back 5

The initiator is decomposed into active free radicals by heat or by an organic accelerator.

Front 6

Is a monomer considered stable or volatile?
What is the boiling point?

Back 6

Volatile

100 degrees C

Front 7

What should you know about the odor of a monomer?

Back 7

Sweet odor that is toxic over a prolonged period.

Front 8

What does the polymerization process do to a monomer?

Back 8

Converts it to a solid with essentially no vapor pressure.

Front 9

In the polymerization rxn. is heat liberated?

Back 9

Yes.

Front 10

In the polymerization reaction, what can excessive heat cause?

Back 10

Vaporization of monomer (porosity)

Can cause tissue damage.

Front 11

In the polymerization reaction will we see expansion or contraction?

Back 11

Volumetric contraction.

Front 12

Denture-based polymers have _____ thermal conductivity and experience heat distortion at ___ degrees C. They can experience .3-2% linear ________.

Back 12

Low

95

shinkage

Front 13

Denture-based polymers have _______ water sorption. This could cause _________.

Back 13

high, about 2%

expansion

Front 14

Properties of denture-based polymers:
Color?
Taste?
Odor?
Biocompatibility?

Back 14

Good color stability
No taste
No odor
Good biocompatibility

Front 15

The polymerization reaction begins with ____________ and ends with _____________ (chemical).

Back 15

Methyl methacrylate

Polymethyl methacrylate

Front 16

Products that use heat for decomposition of the initiator in the polymerization reaction are called...

Back 16

...heat curing acrylics.

Front 17

Products that use amines for decomposition of the initiator in the polymerization reaction are called...

Back 17

...chemically curing or self curing acrylics.

Front 18

What can be added to a polymer to plasticize it?

Back 18

Oils such as dibutyl phthalate.

Front 19

What are the advantage of heat-cured acrylic base.

Back 19

1. Most popular
2. Lower cost of processing
3. Adequate strength
4. Fairly flexible
5. High resistance fatigue fracture
6. *Less unreacted methyl methacrylate monomer*

Front 20

How are light-cured dimethacrylates supplied?

Back 20

Fully compounded in light-tight packages to avoid premature polymerization.

Front 21

With light cured dimethacrylates, how long must you wait before using it
for an impression?

Back 21

24 hrs. Because there is some shrinkage during that first 24 hours.

Front 22

With light cured dimethacrylates, what is more accurate, dough molding or injection molding?

Back 22

Injection molding.

Front 23

What is the mixing ratio for dough-molding?

Back 23

3:1 (three parts powder to one part liquid).

Front 24

Soft liner polymers
For long-term?
For short-term?

Back 24

Long-term: Acrylic
Short-term: Silicone

Front 25

Prosthetic teeth polymers:
What are the indications?

Back 25

1. Low-stress bearing areas
2. Poor ridges
3. Opposing natural teeth
4. Limited inerarch distance

Front 26

What are the purposes for provisional restorations?

Back 26

1. Maintain abutment relationships
2. Function
3. Esthetics
4. Periodontal Health

Front 27

What is integrity?

Back 27

A microfilled composite (integrity)--automixing delivery system