Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

CSA SR > tooth coloured resto materials 1: resin and bonding materials > Flashcards

tooth coloured resto materials 1: resin and bonding materials Flashcards

1
Q

what are the properties were looking for in a material for a chipped tooth

A 
strong
durable 
aesthetic 
non toxic-safe
needs to resist forces( for posterior) depending on the location in the mouth
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is a composite

A

a product with at least two distinct phases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is the purpose of composite

A

to combine two or more materials to produce one with superior properties

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what does composite contain

A

dental filler, resin matrix and an organic binder

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

can composites bind by themselves

A

no they need a binding agent which helps them bind to the tooth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what are advantages of composite

A 
aesthetics 
conservation of tooth structure 
adhesion to tooth-by binding system
low thermal conductivity
alt to amalgam
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is the MINAMATA convention

A

the UK has signed up to get rid of mercury worldwide- not only in dentistry mostly about environmental conditions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

when did the UK sign the MINAMATA convention

A

2016

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

disadvantages of composite

A

technique sensitivity
polymerisation shrinkage
decreased wear resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is the disadvantage of polymerisation shrinkage

A

this can lead to gaps forming in the composite filling
bacteria can fill this
produce acid
and lead to the carious process all over again

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what acid is used to etch the tooth

A

phosphoric acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what % of phosphoric acid is in the etch

A

37%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

how much % of bacteria spreading reduces with rubber dam isolation

A

98.5%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what are the two types of polymerisation

A

addition

condensation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

how do composite fillings set

A

by free radical addition polymerisation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what are the stages of free radical addition polymerisation

A

activation
initiation
propagation
termination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what is the activation stage

A

chemical activation which requires organic amine and organic peroxide
or light activation camphorquinone and blue light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what is the wavelength of the blue light

A

450-490nm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

how do we measure composite polymerisation

A

FTIR spectroscopy and see the different carbon carbon double bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

how much do dental composites polymerise

A

50-60%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what does poor bonding to teeth lead to

A

poor retention
staining
sensitivity
secondary caries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what are the three materials which bind the filler particles together

A

bis-GMA
UDMA
TEGMA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what is the importance of binding the filler particles together

A

provides workablilty

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

characteristics of bis-GMA

A

extremely viscous

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

why is bis-gma viscous

A

due to large benzene rings

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

how is the viscosity in bis-GMA lowered

A

by adding TEGMA w

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

what happens when TEGMA is added to bis-GMA

A

FREELY MOVABLE
increases polymer conversion
increases crosslinkage
increases shrinkage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what happens when we light cure

A

stress set up at bonding interface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

how do we reduce the shrinkage and stress

A

by adding filler- this doesn’t reduce the volume

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

most common filler materials

A

fine glass fibres of barium or strontium as they add radiopacity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

how much shrinkage are most materials

A

2% linear shrinkage

32
Q

how are fillers classified

A

type of material
size
shape

33
Q

what shape are fillers

A

irregular or spherical

34
Q

why are spherical particles easier

A

easier to incorporate into resin mix leaving less resin mix

35
Q

why do we add different size spherical fillers

A

to fill in all the gaps possible therefore reduce polymer shrinkage

36
Q

what are the typical percentages of resin and filler

A

20% resin

80% filler

37
Q

why do we use fillers

A

we want to reduce
shrinkage
water sorption
thermal expansion

38
Q

what do we want to increase when using fillers

A

tensile strength
modulus of elasticity
abrasion resistance

39
Q

what do you need to add to bind the filler to the polymer

A

coupling agent

40
Q

what are the adv of the coupling agent

A

transfers stresses

41
Q

what do we use as the coupling agent

A

organosilane

42
Q

what end does the siloxane bind to

A

hydroxyl groups on filler

43
Q

what end binds to the resin

A

methacrylate

44
Q

what does the OH groups on the filler bind to

A

siloxane on organosilane

45
Q

what are the disadvantages of organosilane

A

age quickly in the bottle

sensitive to water so breaks down in contact with water

46
Q

what are common silane agents

A

vinyl triethoxysilane

methacryloxypropyltrimethyloxysilane

47
Q

what is the strength of composite

A

170-260 MPA

48
Q

what is the tensile strength

A

30-55mpa

49
Q

what are the three types of composite

A

universal
packable
flowable

50
Q

what is the difference in the three types of composite

A

change is viscosity or filler type

51
Q

what are flowables

A

slightly less filler- lower viscosity

52
Q

disadvantages with flowables

A

less filler therefore more shrinkage and reduced wear

53
Q

what is the ph of phosphoric acid

A

0.2

54
Q

what does etching do to enamel

A

decalcifies part of the enamel rods

55
Q

how long does it take for decalcification to occur

A

5-8 seconds

56
Q

what type of bonding is etching
What strength

A

mechanical with only a strength of 20mpa

57
Q

what is the point of etching

A

removing surface debris
produce 10-20 infold of SA
increase wetting

58
Q

Why is dentine hard to bond to

A

hard to keep dry-23% water

moist living tissue

59
Q

what is the smear layer

A

created by the mechanical cutting of dentine- essentially dentine debris of variable thickness
in addition smear plugs block dentinal tubules

60
Q

what are the benefits of the smear layer

A

can protect dentine and pulp from bacteria

eliminated diffusion of dentinal fluid

61
Q

how do we achieve optimum bonding in regard to the smear layer

A

leave the smear layer
remove the smear layer
the smear layer is modified
the smear layer is partially removed or partially replaced

62
Q

how does composite bond to dentine

A

it is essentially an exchange process involving replacement of minerals (removed by hard dental tissues) by resin monomers which when they set micro mechanically into the porosities

63
Q

what is hybridisation

A

the infiltration of resin monomers into the collagen matrix of demineralised dentine followed by polymerisation

64
Q

what are the steps for bonding to dentine

A

acid etching
primer
bonding adhesive

65
Q

why do we acid etch

A

improves the retention of the restoration
increases the SA
removes smear layer from prep
allows penetration of bonding agent into dentine

66
Q

what do we need to be careful of with acid etch

A

protecting the pulp

67
Q

why do we use a primer
How is it applied

A

improves the wettability of the prep
penetrates etched dentine tubules
applied in a thin layer and air dry but don’t dry too much

68
Q

What is the bonding agent
why is the bonding agent important
How is it applied

A

unfilled or lightly filled resin
adhesive bonds to collagen fibrils in dentine mechanically locks in- hybrid layer
applied in a thin layer

69
Q

how long do we light cure the bond

A

40 seconds- 2x 20 second timing

70
Q

what are the 2 characteristics of primer

A

it is amphiphilic and low viscosity

71
Q

what is added to primer

A

solvents to improve viscosity

72
Q

what are the three types of etch and rinse primers

A

acetone based
ethanol based
water based

73
Q

example of acetone based primer

A

all bond 2

one step

74
Q

example of ethanol based primer

A

optibond

75
Q

example of water based primer

A

scotch bond MP

scotchbond 1

76
Q

what are the advantages of 2 step process of bonding

A

application time is lower

technique sensitivity is lower

CSA SR (52 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions