Brainscape's Knowledge GenomeTM

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


See full index

Dental Materials > Cements 3 > Flashcards

Cements 3 Flashcards

1
Q

Uses of glass ionomer cements

A
  • cavity base/lining
  • luting
  • filling
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

GIC is a development of what?

A
  • polycarboxylates
  • change zinc oxide to glass particles
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How is GIC a lining/base?

A
  • under amalgam or composite
  • sandwich technique for composite
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Luting with GIC is used in which departments?

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

How is GIC used for fillings?

A
  • use product specifically designed for restorative purposes
  • ISO standards type I and II
  • class V, III and I and I in deciduous teeth
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

GIC are also called what?

A

polyalkenoates

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

Composition of GIC

A
  • hand mix or encapsulated
  • powder is aluminosilicate glass made from aluminium oxide, silicon oxide and calcium fluoride
  • liquid is aqueous solution of polyacid, originally acrylic acid but also maleic, itaconic or copolymers
  • more recently polyvinyl phosphoric acid (much stronger)
  • or anhydrous cements (powder containing freeze dried acid) and water
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

GIC setting reaction

A

acid +base _> salt and water
- MO.SiO2 + H2A -> MA + SiO2 + H2O

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

GIC setting is complex. Gove the 3 overlapping steps

A
  • dissolution (acid and glass particles react)
  • gelation (crosslinking due to calcium ions reacting with polyacid)
  • hardening (crosslinking due to aluminium ions reacting with polyacid)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Initial setting and maturation of GIC

A
  • water exposure can effect setting - dilutes acid
  • can lead to weak cement (chalky appearance)
  • need to protect - varnishes sold by manufacturers
  • dentine bonding agents often used - may leave a ledge (need to deal with it to prevent biofilm formation)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What acid is often added to GICs?
Why?

A
  • tartaric acid
  • helps break down glass particle surface
  • reacts with aluminium ions
  • extends WT - only calcium ions reacting with glass
  • once tartaric acid used up, aluminium ions reacts with glass
  • GICs have better WTs and STs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Structure of GIC

A
  • final cement has a cored structure
  • glass particles surrounded by polyacid matrix
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What properties are effected by porosity?

A
  • method of mixing
  • cement viscosity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How does method of mixing influence porosity?

A
  • hand mixing is difficult to accurately proportion components
  • mechanical means it’s already proportioned by manufacturers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Cement viscosity - how does that affect porosity?

A
  • luting cements have lower viscosity
  • restorative cements have higher
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Ketac-Cem is a … cement whereas Ketac-Molar is a … cement

A
  • luting
  • restorative
17
Q

For lower viscosity GICs, like … and …, which mixing process is used? Why?

A
  • liners and bases
  • hand mixing - mechanical mixing causes bubbles to form like froth
18
Q

For higher viscosity GICs like for …, what mixing is used? Why?

A
  • restorations
  • mechanical mixing
  • not significant difference ijn porosity and less technique sensitive
19
Q

GICs are strong/brittle
Explain

A
  • brittle
  • low tensile and compressive strength (stronger in compression)
  • weak in thin sections
  • porosity significantly effects properties
  • limit of applications
20
Q

GICs are radiolucent/opaque.
Explain

A
  • originally low to no radio-opacity
  • radio-opacifiers added but until recently compromised appearance
  • glasses containing Sr, Zr not common so radio-opacity improved
21
Q

Are GICs moisture sensitive?

A
  • requires protection during setting
  • and if other procedures require a dry field
  • dessication can cause fracture of the GIC
22
Q

Are GICs biocompatible?

A
  • acids used tend to be weak acids with large molecular weight
  • some concerns with release of aluminium ions - possible link to neurological conditions
23
Q

Thermal properties of GICss

A
  • thermal insulator
  • similar coefficient of thermal expansion to dentine
  • low instance of marginal staining (compared to composite)
  • doesn’t shrink of setting, adheres to enamel and dentine
24
Q

Adhesion of GIC to enamel and dentine

A
  • chemically bonds to enamel and dentine
  • similar to polycarboxylates - COO- group bonds to calcium ions
  • bond strength is low but sufficient for erosion cavities
  • limit of bond strength primarily due to low GIC tensile strength
25
Q

How to improve bond strength of GIC?

A
  • acid etching
  • citric acid is too strong and demineralises dentine
  • polyacrylic acid removes debris without demineralising
26
Q

GIC can bond strongly to what?

A
  • metals and alloys
  • makes it a good luting agent
27
Q

Aesthetics of GICs

A
  • range of shades available - not as wide as composite
  • difficult to colour match - GIC will change shade as it sets
  • ratio of aluminium to calcium important - more aluminium, means less tooth-like
28
Q

Solubility of GIC

A
  • care needed in setting or if dry field needed in another procedure
  • once set GICs have good stability in aqueous environment
  • are susceptible to erosion in low pits
29
Q

Fluoride release from GICs

A
  • initial burst release
  • decreases over time
30
Q

Fluoride recharge in GICs

A
  • fluoride can be reloaded into the material
  • fluoride released similar to initial performance
  • many potential sources (tap water, toothpaste, gels)
31
Q

Is fluoride release from GIC beneficial?

A
  • no clear evidence it is
  • possible benefits for high caries risk and poor dexterity patients
32
Q

Uses of GIC

A
  • filling (specific restorative ones, for Class I and II in deciduous, III and V)
  • sandwich technique
  • liner/base
  • luting
  • orthodontics (bands, brackets)
33
Q

Differences in GICs for luting than those for restoration

A
  • similar
  • smaller glass particles for a thin film
  • thinner mix for this thin film
  • vary Al/Ca for rapid setting
  • add BaO for radio-opacity
  • stronger
  • adhesion is tooth and stainless steel
  • fluoride release
  • moisture sensitive
34
Q

Explain ART

A
  • atraumatic restorative therapy/treatment
  • GIC formulations altered to allow treatment in economically developing world
  • don’t need complex equipment to place
  • compositions prioritise strength over appearance
35
Q

Explain metal additions to GICs

A
  • called cermets
  • additions to increase strength
  • compromised appearance
  • clinical performance was poor so discontinued
36
Q

GICs have been developed for cores - what is the compromise?

A
  • mechanical properties over appearance
37
Q

Explain resin additions to GICs

A
  • add monomers to improve matrix phase
  • add photo-initiators to improve setting time
  • reduce moisture sensitivity in setting
  • improve mechanical properties

Dental Materials (17 decks)

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