Brainscape's Knowledge GenomeTM

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


See full index

CSA > Tooth coloured filling materials 2 - GICs > Flashcards

Tooth coloured filling materials 2 - GICs Flashcards

1
Q

Name different types of cements

A
  1. Glass polyalkenoate cement
  2. Resin modified glass polyalkenoate
  3. Polyacid modified resin cement
  4. composite
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
1
Q

How do we measure wetting of cements

A

measure contact angle between droplet and surface

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

how are glass polyakenoates formed

A
  • result of acid-base reaction between fluoride containing glass and a poly acid
  • adhesive, cariostatic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is the composition of glass polyakenoates

A

fluroro- alumina- phosphor- silicate glass
- poly acid eg.
poly acrylic acid
polymaleic acid

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

what is the setting reaction of GIC involve?

A

Poly acid + base > poly salt +water
- decomposition
- migration
- gelation
- post set hardening
- maturation

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

what are the disadvantages of GICs

A
  • technique sensitive
  • moisture senstivity
  • cannot be placed in stress bearing areas
  • low tensile and fracture toughness
  • poor wear resistance
  • only average aesthetics
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

describe the process of setting reactions

A

Hydrogen comes off carboxylic acid and attacks glass particles
the glass particles then releases ions and then releases fluorine
- Ions come out into matrix and cross lining polyacrylate chains
- final material consists of matrix and glass particles sitting in matrix have ion efficient depleted layer

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

what happens In maturation of GICs

A
  • precipitation of aluminium salts continues for 24 hours
  • the setting process continues thereafter but at a very slow pace for up to 1 year
  • continued formation of polysalts
  • hydration of poly salts
  • expanded gel structure
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what about fluoride in the setting reactions?

A

Fluoride is not an integral part of the matrix and can be released without upsetting the structure of the cement

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

What role does water play?

A
  • slowly hydrates the mature cross linked matrix
  • increased strength
  • improved translucency
  • increased resistance to desiccation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is sensitive tot the setting reaction

A
  • moisture sensitve
  • excess water increases risk of contamination
  • more opacity and strength/hardness decreases
  • loss of water can lead to desiccation which can increase grazing and cracking
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How does the GIC bond to the tooth

A
  • bonds directly to the tooth
  • bonds better to enamel but can bond to collagen
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How are the fluoride ions released?

A
  • Fluoride ions are released from the glass by the acid attack
  • the ions lie free within the matrix and can be released from the restoration into the surrounding tooth structure
  • this contributes to the biocompatibility of the material and also the capacity to inhibit recurrent caries

they are released:
- a rapid initial process responsible for the early burst of fluoride release
- second slower and much sustained process responsible for the long term release of fluoride

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

what does fluoride help in caries

A
  • prevents secondary caires as it promotes remineralisation in adjacent area
  • main reason for replacement of GIC restoration is secondary caries
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How is GICs biocompatible

A
  • plaque does not thrive on glass ionomer surfaces
  • Streptococcus mutant growth is inhibited by GIC restorations due to fluoride present
  • the soft tissue response to GIC is favourable as shown by gingival tissue response to class V restorations
  • plural response is favourable
  • freshly mixed cement pH of 0.9 to 1.6 but very mild inflammatory response
  • direct capping material as it promotes dentine bridge formation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

describe the applications for glass ionomer cement?

A
  • cementation of rigid restorations
  • restorations of primary teeth
  • Class III and V carious lesions
  • Crown margin repair
  • temporary dressing -c various cavity
  • temporary dressing - fractured tooth
  • base under amalgam and composite
15
Q

what are CERMETS

A
  • silver particles fused tot eh glass. Mixture is then re ground
  • limited clinical use due to poor aesthetics
  • mechanical properties no better than normal GPC
16
Q

what are indications for cermets

A
  • core build up
  • low coefficient of thermal expansion
  • good adhesion
  • brittle
  • F- releasing temporary restorations
17
Q

what are some alternative cements?

A
  • diamond carve and diamond 90
  • glass polyalkenoates
  • based on glass and co-polymer of
    polyvinylphosphonic acid
    poly acrylic acid
18
Q

what are some viscous glass polyalkeonates?

A

e.g fuji IX, Ketch molar, Hi dese
higher powder: liquid ratio
- Low water content
- smaller glass particles
-= packable? greater strength
- used in ART technique

19
Q

what are posterior survival times of amalgam and GIC?

A

amalgam - 11 years median
GIC- 6 years median

20
Q

what are RMGICs and what amount of resin is found in set cement?

A
  • RMGICS are glass ionomer cements with the addition of a small quantity of resin components
  • the resin in set cement = 4.5 -6%
20
Q

Name soem advantages of RMGICs

A
  • tooth coloured
  • improved aesthetics
  • medium fluoride release
  • ’ recharges’
  • short setting/ longer working
  • decreased moisture sensitvity
  • improved tensile strength
  • sets on command
  • better wear characteristics
  • easier to use
  • higher bond strength to composite
  • fewer steps than composite
  • can finish immediately
21
Q

what are 2 modifications to conventional GICs

A
  • less water - replaced by a water/ HEMA mixture (vITREMER)
  • modification of the poly acid with side chains that can polymerise by light curing mechanism
22
Q

what else does the polymer contain aswell as acid base reaction

A
  • polymerisable functional groups
23
Q

what is HEMA?

A

Hydroxyl Ethyl Methacrylate
- severely irritating to the eye and is known contact allergen. A small percentage of the population is known to have an allergic response to acrylate resins.
- to reduce the risk of allergic response , minimise exposure to these materials. In particular exposure to uncured resin should be avoided
- Use of protective gloves and no touch technique is recommended

24
Q

why are indications for RMGIC and advantages?

A

Indications
- cervical and root caries
- base
- abfraction lesions
Advantages
- resistant to desiccation
- can be contoured immediately

25
Q

what is the composition of composites

A

bis -GMA or UDMA
- EGDMA
inorganic filler
silage coupling agent
U. v stabilisers
inhibitors

26
Q

what is the composition of dytract

A
  • UDMA resin
    TCB resin
    strontium fluorosilicate glass
    ignitors
    stabilisers
27
Q

how are compomers formed?

A
  • formed from new monomers which contain acidic and acrylate groups
28
Q

what is the 1st stage of the setting mechnism

A
  • light curing induces polymerisation of the resins
29
Q

what is 2nd stage of setting mechanisms

A

after water uptake, the acid- base reaction takes place, resulting in further corsslinking of matrix

30
Q

what are the pros and cons of composite

A
  • excellent handling
  • command set
  • good strength
  • poor adhesion
  • low fluoride release
  • needs a bonding agent
31
Q
A
31
Q
A

CSA (32 decks)

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