Provisional Materials

Question 1

What are the three most common provisional methods

Answer 1

direct
PVS impression or clear stent
integrity or tempbond

Question 2

What are the three categories of failure of a provisional

Answer 2

re-cemented
re-contoured
remade

Question 3

What is the failure rate of provisionals in dental school (UNC)

Answer 3

18.75%

Question 4

What was the median time for failure of provisionals

Answer 4

12 days

Question 5

What are five risk factors that could increase the risk of a molar provisional failing

Answer 5

isolation
clinical crown height
occlusal forces
lateral interferences
reuse of existing provisional at the time of the finalized prep

Question 6

What are eight properties of an ideal interim material

Answer 6

convenient handling; adequate working time, easy molding, rapid setting time
biocompatible
dimensionally stable
ease of contouring/polishing
adequate strength/abrasion resistance 
good appearance
patient acceptability
ease of adding/repairing
chemical compatibility with luting agents

Question 7

What type of material are the acrylics

Answer 7

plastics

Question 8

What type of material are the BisAcryls

Answer 8

composites

Question 9

Which material are the dimethacrylates

Answer 9

bisAcryls

Question 10

Which material are the monomethacrylates

Answer 10

acrylics

Question 11

What are the two types of acrylics

Answer 11

polymethyl methacrylate

polyethyl methacrylate

Question 12

What are the two types of BisAcryls

Answer 12

BisGMA based (most common)
Urethane dimethacrylate base

Question 13

Which one, Jet or Trim, is a polymethyl methacrylate

Answer 13

Jet

Trim is a polyethyl methacrylate

Question 14

Which material is tough, but soft, and melt

Answer 14

monomethacrylates

Question 15

Which material is brittle, hard, and will burn

Answer 15

dimethacrylate; composites

Question 16

What are the four stages of free radical polymerization

Answer 16

activation (light, mixing, etc.)
initiation
propagation
termination

Question 17

What is the change in density from a liquid monomer to a solid polymer

Answer 17

the density increases

low density → high density

Question 18

The change in density is realized through what

Answer 18

shrinkage

Question 19

Once the polymerization reaction starts, it can be what

Answer 19

be very fast and generate lots of heat

Question 20

How can you reduce shrinkage

Answer 20

add fillers; PMMA, PEMA beads

Question 21

What are the three components of monomer liquids

Answer 21

monomer
inhibitors
1/2 chemical initiators

Question 22

What are the three components of the powder

Answer 22

polymer beads
colorants
1/2 chemical initiators

Question 23

What is the purpose of the separate chemical initiators in the liquid and solid

Answer 23

This is why you cannot mix liquids from one system into powders of another

Question 24

These are based on “composite” technology; higher molecular weight monomers “oligomers”

Answer 24

BisAcryl materials

Question 25

Bis Acryl materials have reduced what

Answer 25

shrinkage

Question 26

This filler is used to control fillers

Answer 26

silicate glasses

Question 27

What are two properties of silicate glasses making it a good filer

Answer 27

strengthen

optical properties

Question 28

What are four disadvantages of BisAcryls

Answer 28

limited shades
expensive
brittle
alteration and repair difficult