Brainscape's Knowledge GenomeTM

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


See full index

2nd Year > Dental Materials > Flashcards

Dental Materials Flashcards

1
Q

what are the types of amalgam?

A

conventional

high copper

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

what is the composition of conventional amalgam?

A 
65% silver
29% tin
6% copper
2% zinc
3% magnesium
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is the composition of high copper amalgam?

A 
40% silver
32% tin
30% copper
2% zinc
3% magnesium
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what are the types of alloy morphology that amalgam can come in?

A

lathe cut

spherical

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

what is the action of the silver tin compound in the amalgam?

A

undergoes setting reaction

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

what is the action of the copper in the amalgam?

A

strengthens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is the action of the zinc in the amalgam?

A

scavenger for oxygen

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

when does amalgam reach its final strength?

A

24 hours

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

what is creep?

A

amalgam flows manifesting as protrusions at the restoration margins
= produces fractures and ditching

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

what causes creep?

A

gamma 2 phase

corrosion of the alloy causes mercury to escape into the crevice = causing expansion

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

what benefits do corrosion products give?

A

marginal seal

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

what removes mercury from the amalgam?

A

packing and condensation

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

what are the benefits of bonded amalgam?

A

reduced prep needed
reduced marginal leakage and post op sensitivity
reinforced tooth structure

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

what is the composition of the resin matrix in composite?

A

methacrylate/dimethacrylate monomers - BISGMA

comonomers - TEGMA

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

what is the action of the TEGMA?

A

controls viscosity

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

what is the action of the C to C double bond in composite?

A

allows free radical polymerisation

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

what are siloranes?

A

contain oxiranes = ring opening polymerisation

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

what is cationic curing?

A

camphorquinone causes ring opening polymerisation

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

what is the filler in composite?

A

quartz, silica, glasses - aluminasilicate, boro silicate, barium oxide

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

what is the coupling agent in composite?

A

gamma silane

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

in what ways can composite be activated?

A

chemical

light - camphorquinone

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

what does camphorquinone do?

A

yields necessary free radicals to start polymerisation

generated by quartz halogen lights `

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

what is the job of the coupling agent?

A

transfers stess generated under occlusal loading from rigid brittle filler to ductile polymer matrix

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

what is the job of the filler?

A

shock absorber

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

what are the 4 types of composite?

A

conventional
microfilled
hybrid
nanocomposites

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

what is the difference in flowable composite compared to conventional?

A

less filler

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

what is GI?

A

ion leachable glass and polycarboxylic acid

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

what is the composition of the powder to liquid GI?

A

p - sodium aluminasilicate glass + 20% CaF

l - aqueous solution of acrylic acid copolymer and tartaric acid to control the set

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

what is the set reaction of powder and liquid GI?

A

acid base reaction

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

what is the set reaction of powder and water GI?

A

p - sodium aluminasilicate glass + 20% CaF, vacuum dried polyacid

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

what does hand spatulation when mixing GI cause?

A

increased air incorporation

increased porosity

32
Q

how does GI bond to tooth surface?

A

by calcium ions

33
Q

how does GI bond to collagen?

A

H bonding - metallic ion bridging

34
Q

how can you boost the tooth to GI bond?

A

citric acid - removes smear layer

polyacrylic acid - increases bond strength

35
Q

what are the properties of GI?

A 
F release and uptake
brittle
poor abrasion resistance
acid eroded
non radiopaque
36
Q

what is a cermet?

A

silver pelletized mix of glass and metal particles
radiopaque
f release
increased strength

37
Q

what is RMGIC?

A

modified composite
giomers
RMGIC

38
Q

what is modified composite?

A

filler of aluminasilicate glass = encourages F release

light cured free radical polymerisation

39
Q

what is a giomer?

A

filler = aluminasilicate glass pre reacted with polyacid is pre reacted with glass polyalkenaote complex

40
Q

what is the composition of RMGIC?

A

p - ion leachable glass
l - methacrylate resin - polymerisation set, polyacid - acid/base reaction, HEMA - allows acid and resin to coexist, water - ionisation for acid/base reaction, polymerisation activators and stabilisers

41
Q

when you start to mix P and L of RMGIC what happens?

A

acid base reaction starts
light activation sets off polymerisation
chemical activators - moves more rapidly

42
Q

what can happen to RMGIC’s?

A

shrinkage

expansion in water

43
Q

why is adhesion of RMGIC’s limited?

A

lack of free acid
lack of sufficient ionic character
lack of mobility of active species

44
Q

what is the make up of a phosphoric acid cement?

A

p - ZnO and other metallic oxides

l - aqeous solution of phosphoric acids and buffers of aluminasilicate phosphate and zinc phosphate

45
Q

how to phosphoric acid cements set?

A

sets at surface of powder

rapid and exothermic

46
Q

what are the properties of phosphoric cement?

A 
low pH/MW = highly irritant
thermal and electrical insulator
strong
radiopaque
good compatibility
not obtundant 
non adhesive - no coronal seal
47
Q

what is a variant of phosphoric cement?

A

silicophosphate cements
p - aqueous phosphoric acid and buffers
l - zinc oxide and aluminasilicate glass
stronger, less soluble, leaches F

48
Q

what is the composition of copper cement?

A

p - zinc oxide, black copper oxide

l - zinc oxide, aluminosilicate glass

49
Q

what is the composition of zinc oxide eugenol?

A

p - ZnO and hydrogenated resin, accelerator - zinc oxide and aluminosilicate glass
l - eugenol and olive oil to control viscosity

50
Q

how does zinc oxide eugenol set?

A

chelation

51
Q

what are the properties of zinc eugenol?

A 
beneficial irritancy
bacteriocidal due to zinc
radiopaque zinc
incompatible with resin composites
non adhesive - no coronal seal
insulator
obtundant
52
Q

what is orthoethoxybenzoic acid?

A

stronger than zinc oxide eugenol
p - quartz
l - orthoethoxybenzoic acid/eugenol

53
Q

what is the composition of chemically activated calcium hydroxide?

A

glycol salicylate

zinc oxide calcium hydroxide

54
Q

what is the composition light activated calcium hydroxide?
how is it activated?
what increases its rate of set?

A

methacrylate monomer - BISGMA mixed with HEMA
polymerisation activation
moisture increases rate of set

55
Q

what are the properties of calcium hydroxide?

A 
high pH - beneficial irritancy
high pH - bacteriocidal
insulates
radiopaque
compatible
not strong and no seal
56
Q

what is the composition of polycarboxylates?

A 
p = zinc oxide
l = aqueous solution of polyacrylic acid
57
Q

how do polycarboxylates set?

A

acid base reaction

58
Q

what are the properties of polycarboxylates?

A 
acidic - high MW = reduced penetration and mildly irritant
F = bacteriostatic
stong, insulative, compatible
adhesive
no seal, not obtundant
59
Q

what are the properties of GI?

A

high mw = mild irritant
bacteriostatic due to F release
insulates
strong, adhesive, compatible

60
Q

what 3 ways can adhesion be achieved by?

A
  • micromechanical attachment - etch/resins
  • chem adhesion to enamel and dentine - coupling agents/cements
  • complex - wetting, penetration - modern bonding agents
61
Q

what is acid etch?

A

acid gel
selective decalcification of enamel prisms
micromechanical tags into which bonding resin can flow

62
Q

what are the effects of acid etch?

A

increased surface roughness
increased enamel surface energy - removes surface contaminants, increases wetting, facilitates micromechanical attachment

63
Q

what happens if you etch for too long?

A

calcium phosphate re precipitate

64
Q

why do you wash away etch?

A

remove debris

65
Q

why do you dry after washing etch away?

A

enable hydrophobic resin to penetrate and attach

66
Q

what is a primer?

A 
dentine conditioner 
acid
maleic acid, oxalic acid, phosphoric acid, nitric acid
acid/base reaction with hydroxyapatite 
opens tubules
67
Q

what is a coupling agent?

A

primer
sticks
bonds hyrophobic material to hydrophillic dentine
HEMA

68
Q

what is a sealer?

A

sealant flows into tubules and seals dentine with methacrylates, ensures bond
BISGMA
TEGMA

69
Q

what are the benefits of ormocers as opposed to composites?

A

less shrinkage

no residual monomers

70
Q

what are the types of impression materials?

A

non elastic - impression compound/plaster, zinc oxide and eugenol pastes
elastic - hydrocolloids - reversible//irriversible
synthetic elastomers - polysulphides, silicone rubbers, polyethers

71
Q

what are hydrocolloids?

A

colloidal suspension of polysulphides in waterb

soluble or gel

72
Q

what is agar?

A

complex polysaccharide from seaweed gel
borax - gives body
potassium sulphate - counteracts retardent effects of gypsum

73
Q

what are the advantages of agar?

disadvantages?

A

A- reversible, takes up moisture

D - complicated equipment, cost, cross infection

74
Q

what are alginates made up of?

A

Na/K salt of alginic acid
CaSO42H2O - source of Ca for cross linking
sodium phosphate - controls working time
inert filler - body for manipulation

75
Q

how does sodium phosphate control the working time?

A

limits the availability of calcium ions

2nd Year (4 decks)

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