Brainscape's Knowledge GenomeTM

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


See full index

BDS3 > Dental Materials > Flashcards

Dental Materials Flashcards

1
Q

What is the difference between an adherent and an adherend? Give an example for each.

A

adherend = the surface/substrate being bonded to
e.g. enamel, dentine, alloy, ceramic

adherent = the substrate doing the bonding
e.g. CR, GIC, acrylic, ceramic

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

How do we usually bond ceramic to metal? What type of bond is this?

A
  • Metal is heated (~1000degC) forming an oxide layer (black surface) which is ready to bond with ceramic
  • Very strong chemical adhesion (oxide layer and ceramic)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How do we usually bond a ceramic crown to a tooth?

A
  1. Adhesive/primer on enamel/dentine
  2. Resin cement layer
  3. Silane layer (replaces metal primer)
  4. Ceramic crown
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the most distinctive chemical in silane?

What type of bonding does silane use?

A
  • Silicon

- Ester bond (silane esters)

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

How do we usually bond metal (e.g. gold) to resin cement?

A

Metal primer

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

What makes up the ‘glass’ component in GIC and what does it do?

A

Calcium and aluminium (derived from glass) act as the base in the GIC acid/base reaction

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

What is the MoA of metal primer?

A

Bifunctional (like an amphipathic molecule)

C= group bonds to resin and -O- containing groups bond to metal.

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

What is one way to improve the retention when using metal primer?

A

Sandblasting (NOTE: we don’t sandblast ceramic, but use hydrofluoric acid)

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

What is the difference between adhesive and cohesive failure?

A

Cohesive failure is within the material or adhesive layer. (e.g. within resin cement layer or CR layer)

Adhesive failure is failure between dissimilar materials.
(e.g. between CR and adhesive, or ceramic and cement.

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

How does dentine differ from superficial vs. closer to the pulp

A

Tubules are larger in diameter and in greater density/numbers

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

True or false: Tertiary dentine is spongier than primary/secondary dentine.

A

False, tertiary dentine is stiffer.

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

What toothwear pattern might someone with Class II Div 2 occlusion have?

A

Thin incisal edges that are difficult to restore.

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

What are TWO ways in which xerostomia may impact on restoration longevity?

A
  • Increased caries risk

- Too dry/dessicated for GIC -> brittle

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

What are FOUR factors associated with cavity prep that may influence adhesion to tooth structure?

A
  • “Wetness”, particularly on dentine
  • Cavity size (resistance/retention)
  • Smear layer, pellicle
  • Foundation of bonding substrate (e.g. infected dentine)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the percentage (by weight) compositions of enamel?

A
  • 97% HA
  • 2% water
  • 1% organic material (amelogenins)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the percentage (by weight) compositions of dentine?

A
  • 70% HA
  • 20% organic material (90% collagen)
  • 10% water
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the percentage mineral (HA) content of cementum?

A

45-50% HA

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

What is problematic about aprismatic enamel?

A

Etching aprismatic enamel leaves a relatively flat surface with little retentive features (ie. no keyhole structure) resulting in weak micromechanical adhesion.

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

Air from the triplex is a major source of moisture. How long do we have to spray it to purge the water?

A

10-15secs of air spray.

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

What are TWO examples of a hybrid zone/layer?

A
  • GIC on dentine

- Adhesive resin and primer on dentine

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

Where specifically in the dentine do resin tags most commonly form, intertubular or intratubular dentine?

A

Intertubular dentine. This is the portion that gets demineralised by the etch.

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

Where would you find intratubular dentine?

A

Lining the dentinal tubule.

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

What does etch remove in dentine?

A
  • Mineral (HA)
  • non-collagenous proteins
    (It leaves the collagen framework)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

True or false: dessicating dentine after etching will cause the collagen framework to irreversibly collapse.

A

False, although collapsed collagen matrix forms hydrogen bonds with each other, these bonds are broken when primer is applied.

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

Why are we taught to dry but not dessicate dentine after using conditioner?

A

So it’s not too dry nor wet for the RMGIC/GIC.

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

What is the main component of primer?

A

HEMA

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

What is the MoA of wet bonding and why might this not work in real practice?

A

MoA: dentine partially dried, then acetone-based primer used to ‘chase’ the rest of the water out

Issue: Acetone evaporates before it can get to the water, leaving water behind to form water blisters in the hybrid layer that can block formation of resin tags, resulting in weaker bond.

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

True or false: HEMA primer is hydrophilic.

A

True, this is why the hybrid layer is susceptible to breakdown via dentinal fluid, causing HEMA to leach out.

29
Q

What is the difference between microleakage and nanoleakage?

A
  • Nanoleakage is smaller and occurs with any bonding technique (including GIC)
  • Nanoleakage is too small for bacteria to enter through
  • Clinical significance of nanoleakage unclear (may develop into microleakage)
30
Q

What functional group of HEMA primer binds with dentine?

A

hydroxyl (-OH) group

31
Q

What are the THREE main types of adhesive systems and their corresponding generations?

A
  • Etch and rinse (4th and 5th)
  • Self-etch (6th and 7th)
  • Universal (8th)
32
Q

How do 4th generation adhesives differ from 5th?

A

Primer and adhesive combined in 5th

NOTE: 4th gen is 3-step gold standard.

33
Q

How do 6th generation adhesives differ from 7th?

A
  • 6th has self-etch and primer combined

- 7th is one-step

34
Q

Why does HEMA primer evaporate?

A

It contains an organic solvent (e.g. ethanol/acetone)

35
Q

What are TWO weaknesses of self-etch systems vs. total etch?

A
  • Weaker acid (shallower resin tags)

- Components unstable (phase separation if too much water)

36
Q

Why might primer/adhesive combinations undergo phase separation?

A

The hydrophilic (HEMA - primer) and hydrophobic (Bis-GMA, TEGDMA) components are unstable.

37
Q

What is the main bonding component/s of G-BOND?

A
  • 4-MET (no HEMA)

- Phosphate esters

38
Q

What functional group does 4-MET use to bond to tooth structure?

A

Carboxyl (-COO) group bonds to Ca2+ on tooth structure

39
Q

What generation adhesive is G-BOND?

A

7th generation (1-step)

40
Q

What type of bonding does G-BOND use?

A

Chemical/ionic bonding (-ve group -COO or PO4-3, +ve group Ca2+)

41
Q

What generation adhesive is G-Premio?

A 
8th generation (compatible with total etch or you can just use the self-etch in G-Premio itself)
G-Premio uses 4-MET as primer, not HEMA.
42
Q

What are the FIVE clinical steps for applying G-premio?

A
  1. Etch with 37% orthophosphoric acid for 15secs (or no etch)
  2. Apply G-Premio to all surfaces and leave for 10secs
  3. Dry for 5 secs at MAX air pressure
  4. Light cure for 10 secs
  5. Add CR increments
43
Q

What is ONE way G-Premio might achieve greater bonding vs. 3-step adhesive gold standard with HEMA primer?

A

The primer/adhesive component in G-Premio might have greater wettability vs. HEMA primer
= longer resin tags

44
Q

True or false: Dentinal hypersensitivity can present with persistent dull, throbbing ache.

A

True, therefore it is important not to assume that lingering pain is due to irreversible pulpitis.

45
Q

Why does dentinal hypersensitivity most commonly affect 20-40yo and not younger or older?

A
  • Younger = enamel usually doesn’t have much time to wear

- Older = more secondary dentine with age (this is also why teeth appear more yellow)

46
Q

How might vital bleaching (used to whiten teeth) cause dentinal hypersensitivity?

A 
The bleach (H2O2) travels to the dentine through the enamel and down the dentinal tubules to trigger the nerves in the pulp.
NOTE: Bleach does not cause tooth erosion (they are alkaline, not acidic!)
47
Q

What might be more effective (and still conservative approach) to a once-off duraphat application for dentinal hypersensitivity?

A

Frequent at-home toothpaste application

48
Q

What concentration is Duraphat and how does it work to treat dentinal hypersensitviity?

A

22600

- CaF2 globules on tooth surface at neutral pH -> HA formation at acidic pH

49
Q

Why might frequent toothpaste application be unsuitable for management of erosion in a wine taster?
What is a suitable alternative?

A

Toothpaste alters taste = bad for wine taster!

Better to use tooth mousse.

50
Q

How does potassium nitrate help with dentinal sensitivity?

A

It increases the extracellular potassium levels so the neurons have a hard time repolarising (K+ cant move outward), therefore nerve stops firing.

51
Q

When treating dentinal hypersensitivity with protective adhesive layer, why might it be better to use self-etch rather than total etch?

A

Total etch requires thorough drying, which may be quite uncomfortable for the patient.

52
Q

What are the components of bioglass?

How does it work?

A

SiO2, CaO, Na2O, P2O5, MgO

  1. Bioglass + saliva = Ca2+, PO4(3-), Si4+ dissolve at glass interface
  2. Precipitation of hydrated Si-gel
  3. Si-gel acts as template for CaPO4 -> crystallises into HA
53
Q

How does arginine + CaCO3 in Pro-Argin technology work?

A

Tooth surface has a overall negative charge, arginine is positively charged and binds to dentine with CaCO3 to block tubules.

54
Q

What is the activating reaction for silane? How does it bond with ceramic?

A
  1. Z-(CH2)n-Si-(OR)3 + H2O (acidic)
  2. (OR)3 -> (OH)3
  3. OH on silane and ceramic -> ester bonds (Si-O-O-Si)
55
Q

How does silane help bond ceramic to resin?

A
  • OH on silane forms ester bond with OH on ceramic (also has H-bonding between non-reacted OH groups)
  • Organic functional group (C=C) bonds with resin
56
Q

What is the advantage of having smaller particle size as fillers in CR?

A

Better aesthetics (easier to polish)

57
Q

What is ONE main feature that is improved with newer generation resins?

A

Lower shrinkage

58
Q

What are three different resins and their strengths?

A
  • BisGMA (highly viscous)
  • TEGDMA (dilutant)
  • PEGDMA (low shrinkage)
59
Q

Give ONE example for a nanofill CR and nanohybrid CR.

A
  • Nanofill: Filtek supreme

- Nanohybrid: GrandioSO (contains micro and nanoparticles)

60
Q

What is the average filler percentage for CRs?

A

60-70%

61
Q

How does filler differ in packable composites?

A
  • Greater filler % (~80%)

- Larger filler particles

62
Q

What does an initiator in CR produce? How does this help CR polymerisation?

A
  • Initiators produce free radicals
  • Free radicals bond to C=C bonds, forming a free radical out of the organic monomer that can then polymerise with more monomers
63
Q

Give ONE example of an initiator in chemical cured CR and for light cured CR.

A
  • Chemical: Benzoyl Peroxide

- LC: Camphorquinone

64
Q

What are silorane based CRs?

A

Silorane is a ring shaped organic monomer that opens when polymerising, resulting in very little space change during polymerisation (shrinkage = 1%)

NOTE: currently restricted to posterior CRs.

65
Q

What are Bulk Fill CRs? What are TWO advantages? Give ONE example.

A
  • Bulk fill CRs = monomers quite large, so overall number of monomers is less = less shrinkage
  • Can be cured in 5mm increments!
  • e.g. Filtek Bulk Fil
66
Q

What are SEVEN physical properties of CR that are tested?

A
  • Stress (F/A) and strain (change in length)
  • Polymerisation shrinkage
  • Compressive strength
  • Tensile strength
  • Flexural strength
  • Wear (2-body, 3-body)
  • Surface roughness
67
Q

What are TWO different ways CR can shrink?

A
  • Towards the light source

- Towards the walls of the cavity if adapted well

68
Q

What is a diametral tensile strength test?

A

Object is squeezed and lateral stretch is measured (used on brittle materials due to gripping problems with normal tensile testing)

69
Q

What is ONE problem with the oxygen inhibition layer of CR?

A

It remains not fully cured and can pick up stains.

BDS3 (22 decks)

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