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BDS2 CLINICAL Dental Materials > Composite > Flashcards

Flashcards in Composite Deck (53)
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1

What is the ideal properties of composite

mechanical (strength, rigidity, hardness)
bonding to tooth/compatible with bonding systems
thermal properties
aesthetics
radiopaque
handling/viscosity
anticariogenic
smooth surface finish/polishable
low setting shrinkage
biocompatible

2

what are the 2 key components of composite resin

glass filler particles
resin material

3

what is the key feature of the filler particles and resin

they are the opposite of each other
resin is soft while the filler is hard

4

what are the 5 components of composite

filler particles
resin
camphorquinone
low weight dimethacrylates
silane coupling agent

5

what are the filler particles

they are made of glass - they are what allow the composite resin to be hard

6

what are examples of glass filler particles

• Microfine silica
• Quartz
• Borosilicate glass
• Lithium aluminum silicate
• Barium aluminum silicate

7

what is hybrid composite

most common
has a little bit of the larger particles and a little bit of the microfine particles
The small particles fill the spaces between the large ones

8

what does more filler mean for the material

it is harder

9

what is the monomers used for resin

BIS-GMA
urethane methacrylate

10

what is BIS-GMA

reaction product of bisphenol-A and glycidyl methacrylate

11

what are the key characteristics of the resin monomer

it is a difunctional molecule and it is essential for the crosslinking required for the polymerization as it has C=C and it undergoes free radical addition polymerization

12

what is camphorquinone

activated by blue light to produce free radical molecules
imitates free radical addition polymerization of BIS-GMA
changes the resin properties to make it stronger

13

is all the monomer reacted?

no the degree of conversion of resin is only 35-80%

14

what is the function of the low weight dimethacrylates

they are added to adjust viscosity and reactivity
It improves the material to adjust its properties as if you cure without it then it sets too quickly and does not give us enough working time.

15

what is an example of a low weight dimethacrylates

TEGDMA

16

what is a silane coupling agent

it allows a bond between the filler particle and resin

17

why do the filler particle and resin not bond without the silane coupling agent

Normally water will adhere to glass filler particles preventing resin from bonding to the glass surface.

18

what is an example of a silane

methacryloxypropyltrimemethoxysilane

19

how does methacryloxypropyltrimethoxysilane work (silane coupling agent)

the methoxy groups hydrolyse to hydroxy group by reacting with the absorbed water or -OH groups on the filler

20

what are the different uses of composite

• It is often used where aesthetics is important
• Class III, IV, & V permanent restorations
• Class II – limited occlusal wear
• Labial veneers
• Inlays, onlays – indirect techniques
• Cores
• Modified forms as luting cements (some dual cured)

21

how is composite classified

filler type
curing method
area of use
handling

22

what type of composite is used for anterior teeth

microfilled or sub micron hybrid

23

what type of composite is used for posterior teeth

heavy filled

24

what type of composite is universal

sub micron hybrid

25

how can composite be classified based on its handling

can be condensable
syringable
flowable

26

what is condensable composite

‘amalgam feeling’ – it is more viscous and is used for packing the cavity in a similar way to amalgam. Has a greater porosity.

27

what is syringable composite

good adaption, less porosities, easy to apply

28

what is flowable composite

lower filler content, more shrinkage, difficult to apply, place for them with fibre ribbons.

29

how can composite be classed on curing method

light cured
self cured

30

what would happen if we stuck to only one size of filer particle

if we only used a large filler particle we would run out of space and we would not be able to fill up the volume but if we put more of the smaller ones then we can get more filler particles per unit volume than if we restricted ourselves to the larger one