Compomers

Question 1

What material have been termed hybrid materials?

Answer 1

compomers and resin modified glass ionomers

Question 2

Why are compomers and resin modified glass ionomers termed hybrid materials?

Answer 2

they have both resin and glass ionomer constituents

Question 3

What is the sequence of compomer, glass ionomer, resin modified glass ionomer and resin composite?

Answer 3

Question 4

Why has compomers been developed?

Answer 4

in an attempt to combine the potential advantages of fluoride release as seen with glass ionomer cements with the advantages of resin composites

Question 5

What is the main system of compomers?

Answer 5

primarily resin system

Question 6

What are compomers manufactured without?

Answer 6

without the addition of water

Question 7

Instead of water, what is incorporated into compomers?

Answer 7

resin

(difunctional)

Question 8

Are resin composites hydrophillic or phobic?

Answer 8

hydrophobic, no water in the material at all

Question 9

How do compomers differ from resin composites?

Answer 9

put an additional difunctional resin in there

become more hydrophilic, allow the uptake of water and promote the release of fluoride ions during its lifetime

Question 10

What is the generic name of compomers?

Answer 10

polyacid-modified resin composite

Question 11

What are the 2 resin components of the compomer?

Answer 11

contains 2 monomeric components:

1) dimethacrylate

2) difunctional resin monomer containing both carboxyl and methacrylate groups

can bind to hydrophobic and hydrophilic

Question 12

What is the difunctional monomer?

Answer 12

TCB resin

Question 13

What is TCB resin?

Answer 13

cross-linking reaction

reaction product of butane tetrecarboxylic acid and (HEMA) hydroxyethylmethacrylate

Question 14

What is the most hydrophilic resin being used?

Answer 14

HEMA

Question 15

What are the hydrophilic monomers? (examples)

Answer 15

glycerol dimethacrylate

Question 16

What does the difunctional resin monomer do?

Answer 16

enhances water diffusion within resin matrix

Question 17

What is the filler/ glass ionomer?

Answer 17

fluoro-alumino-silicate glass

Question 18

What is the filler loading volume of the filler component?

Answer 18

43% and 67%

Question 19

What are the photo-activators and initiators?

Answer 19

camphorquinone

tertiary amine

Question 20

How many stages are in the setting reaction?

Answer 20

2 stage process

Question 21

How is the resin part and glass ionomer part cured?

Answer 21

resin = LC

glass ionomer = chemical

Question 22

What is the primary reaction?

Answer 22

LC

free radical polymerisation reaction

Question 23

What is the secondary reaction in compomer setting?

Answer 23

occurs between the glass and the carboxylate groups of the difunctional resin

Question 24

In the secondary reaction, what is formed?

Answer 24

polysalt matrix is formed around the glass (as conventional gic)

Question 25

What aids the acid/base reaction in the stage 2?

Answer 25

by additions of small parentages of hydrophilic resin

Question 26

What does addition of hydrophilic resin allow?

Answer 26

encourage diffusion of water within the resin and fluoride out

Question 27

What is the secondary reaction?

Answer 27

acid/base

Question 28

What is the polymerisation shrinkage as a percent by volume?

Answer 28

2-3.5%

Question 29

What is needed for compomers to bind to tooth tissue?

Answer 29

an intermediate bonding system

Question 30

Why cant you get the properties of the glass ionomer which bind to tooth surface well?

Answer 30

the components are bunged up in the resin matrix formed in the first reaction it is more similar to resin composite

Question 31

What is fluoride release dependent on?

Answer 31

secondary setting reaction

Question 32

Is fluoride release slow or fast?

Answer 32

slow and steady

Question 33

Is there an initial fluoride burst initially?

Answer 33

no

Question 34

What is the concentration of fluoride within the restoration determined by?

Answer 34

determined by the secondary reaction of glass with the pendent carboxyl groups this in turn is determined by their proximity to the reactive glass surface

Question 35

Why is there limited ability for the reaction between the glass and carboxyl groups?

Answer 35

the resin phase of the system has already set

Question 36

What reaction allows the fluoride o be released?

Answer 36

water uptaken, hydrogen ion reacts with the glass and fluoride is released

Question 37

What permits the uptake of water?

Answer 37

addition of hydrophilic resin systems

Question 38

When has the compomer fully set?

Answer 38

when the water sorption has occurred and the secondary glass filler/carboxyl reaction has completed

Question 39

How long until saturation has occurred?

Answer 39

1 week of placement in the mouth

Question 40

What is the concern of water sorption?

Answer 40

uncontrolled reaction, may lead to excessive expansion - damage to the tooth hydroscopic expansion

Question 41

Why is hydroscopic expansion actually a good thing?

Answer 41

primary reaction there is shrinkage, reduce the effect of polymerisation shrinkage

Question 42

What is the effect of compomers uptaking oral fluids?

Answer 42

leads to discolouration of the entire restoration

Question 43

What is the wear resistance like of compomers?

Answer 43

less wear-resistance compared to resin composites

Question 44

When would you use compomers?

Answer 44

class III cavities class V cavities fissure sealants (flowable form) luting of metal-based indirect restorations and orthodontic brackets (luting form for crowns) restoration of deciduous teeth

Question 45

Would you use compomers for cermaic crowns?

Answer 45

no, the expansion could break cermain crown

Question 46

What cavities would you not use compomers?

Answer 46

class I, II, IV not strong enough

Question 47

Why would you not use compomers for inter-visit restoration of endodontic access cavities?

Answer 47

poor ability to seal as demonstrated with microleakage

Question 48

How is the material presented?

Answer 48

compules, light tight, moisture tight