clinical aspects of composite

Question 1

what is the chemistry of composite

Answer 1

matrix
fillers
coupling agents
initiators and accelerators
pigments

Question 2

what is the composite called if it is just resin matrix

Answer 2

unfilled resin

Question 3

what are the two viscous monomers

Answer 3

BIS-GMA

UDMA

Question 4

what are the two diluents

Answer 4

TEGDMA

HEMA

Question 5

what is step 1

Answer 5

resin matrix

Question 6

what is a matrix

Answer 6

Phase that polymerizes to form a solid mass

Question 7

what are the properties of matrix

Answer 7

absorbs water stains and discolours

least wear resistance

Question 8

what does step 2 include

Answer 8

Silica particles
Quartz
Glass (Ba, Sr, Zr)

Question 9

what is it called when composite is made of resin matrix and filler particles

Answer 9

filled resin

Question 10

what are composites classified by

Answer 10

by filler size( micro filled and nano filled)

Question 11

what determines the surface smoothness

Answer 11

filler size

Question 12

what does the change in particle size lead to

Answer 12

the rougher the surface

Question 13

what does an increase in filler content lead to

Answer 13

increase hardness/strength
increase abrasion resistance
handling
aesthetics

Question 14

what happens as the filler content decreases

Answer 14

the resin content decreases

Question 15

what is step 3

Answer 15

the coupling agent

Question 16

what happens in step 3

Answer 16

the filler particle which is the inorganic matrix binds to the the resin matrix which in organic

Question 17

what is organosilane known as

Answer 17

a bifunctional molecule

Question 18

what does the silane end bond to

Answer 18

OH group of the filler particle

Question 19

what does the methacrylate end polymerise to

Answer 19

polymerises to resin

Question 20

what is step 4

Answer 20

Optical modifiers/Pigments

Question 21

what do Optical modifiers/Pigments do

Answer 21

provide translucency and opacity

Question 22

what do the Optical modifiers/Pigments tend to be

Answer 22

metal oxides of titanium dioxide and aluminium oxide

Question 23

what is the colour shading chart we use for teeth

Answer 23

vita classical

Question 24

what materials are radiopaque

Answer 24

boron or zinc

Question 25

what do we need for a light activated composite- free radical activation

Answer 25

1.For light activated materials: ◦ Photo initiator - camphorquinone ◦ Amine accelerator (diethy-amino-ethyl-methacrylate) ◦ Polymerization inhibitor – hydroquinone (prevents setting during storage)

Question 26

what are examples that give the right wavelength of light

Answer 26

blue light emitting diode plasma arch light argon laser halogen light

Question 27

what is the filler size of macro filled particles

Answer 27

8-12 micrometres

Question 28

what is the filler size of small particle

Answer 28

1-8 micrometres

Question 29

what is the filler size of hybrid

Answer 29

0.4-1 micrometres

Question 30

what is the filler size of micro filled

Answer 30

0.04-0.4 micrometres

Question 31

what is the filler size of nano hybrid

Answer 31

0.02-2.5 micrometres

Question 32

what is the filler size of nano filled

Answer 32

culsters 0.06-1.4 micrometres

Question 33

what is the disadvantages of composite

Answer 33

polymerisation shrinkage technique sensitive- water control doesn't bond to a tooth- need a bonding agent

Question 34

what is shrinkage

Answer 34

the development of gaps

Question 35

what does shrinkage lead to

Answer 35

leads to sensitivity secondary caries staining

Question 36

what do we need for moisture control

Answer 36

good gingival health cotton wool rolls rubber dam

Question 37

Contra - Indications of composite

Answer 37

Where moisture control cannot be achieved • Subgingival restorations • Composite polymerization is reduced in the presence of Eugenol (don’t use with ZoE) Very deep restorations...pulpal irritation due to un set monomers.... (new materials/techiques/ place a linner).

Question 38

what are the stages in the bonding phase

Answer 38

Total etch – etch enamel and dentine for 15 seconds. Wash off all acid for at least 15 seconds dry- slightly for 5-10 seconds

Question 39

what substance do we use to etch

Answer 39

37% phosphoric acid

Question 40

what changes in enamel occur when etching has taken place

Answer 40

creates micro porous layer increases SA increases wettability increases surface energy

Question 41

what changes in dentine occur when etching has taken place

Answer 41

removes smear layer unblocks and widens dentinal tubules orifices exposes network of collagen fibres

Question 42

what do we need to use when bonding

Answer 42

apply primer thin by drying slowly light cure for 20-30 seconds

Question 43

what are bonding agents

Answer 43

chemicals that allow the composite to bond to teeth | the common used technique is 2 step-total etch followed by prime and bond

Question 44

what is the hybrid layer

Answer 44

is the ’zone’ of resin interlocking with demineralised dentine surface. responsible for micromechanical bonding between tooth and resin

Question 45

what wavelength of light is present in the light curing

Answer 45

450-490nM

Question 46

benefits of composite

Answer 46

sets material when you want

Question 47

disadvantages of composite

Answer 47

limited depth for curing only 2mm

Question 48

what is the oxygen inhibition layer

Answer 48

glossy film of uncured resin

Question 49

what can we use for tooth separation

Answer 49

Matrix strip and wedge

Question 50

what can matrix bands and wedges stop

Answer 50

to prevent bonding two adjacent teeth together and to help shape proximal surfaces

Question 51

what do we use to separate teeth on posterior surfaces

Answer 51

matrix bands

Question 52

what do we do after the restoration and and polishing

Answer 52

finishing and polishing

Question 53

what do we consider when finishing a tooth

Answer 53

removal of XS material and get the correct shape

Question 54

what can we use to finish a tooth

Answer 54

finishing burs | abrasive discs

Question 55

why do we polish a tooth

Answer 55

to get a high polish

Question 56

what do we use to polish a tooth

Answer 56

soflex discs | abrasives such as polishing points

Question 57

what are the different type of discs

Answer 57

course medium fine superfine

Question 58

what are interproximal strips

Answer 58

used for removing overhangs | Insert and use below contact area to maintain proximal contact