Brainscape's Knowledge GenomeTM

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


See full index

operative > composite > Flashcards

composite Flashcards

1
Q

What is the definition of an aesthetic restoration?

A

one that simulates the natural teeth in color, translucency, shape, size, form and contour; achieving what is known as invisible restoration that can’t be distinguished from the tooth itself.

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

What are the types of aesthetic tooth-coloured restorations?

A
  • direct: resin composite, glass ionomer and hybrid materials
    combine the benefits of both as resin modified glass ionomer
  • indirect: resin composite or ceramic inlays, onlays & veneers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What does the term composite refer to?

A
  • a material that is composed of two or more constituents that are insoluble in each other
  • this combination produces a
    material with superior or intermediate properties to those of the individual constituents
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are dental resin composites?

A

resulted from mixing the silicate glass particles with an acrylic resin monomer

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

What is the composition of composites?

A
  • orgaic resin matrix
  • inorganic filler particles
  • organic coupling agent
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What does organic resin matrix comprises of?

A
  • high molecular weight monomers
  • low molecular weight monomers
  • activator/initiator system
  • inhibitors
  • pigments
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are high molecular weight monomers?

A
  • most systems are based on bisphenol glycidylmethacrylate (BisGMA) monomer, some are based on urethane dimethacrylate (UDMA) monomer and others incorporate a mixture of both BisGMA and UDMA
  • both resins are extremely viscous.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are low molecular weight monomers?

A

A low-viscosity monomer e.g., triethylene glycol dimethacrylate (TEGDMA) is thus added as a diluent

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

What are activator/initiator systems?

A

direct resin composite systems could be polymerized either through chemical curing (auto- or self-cure), photo-chemical through light activation or dual-cured through both mechanisms

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

What are inhibitors?

A

the inhibitor hydroquinone prevents spontaneous polymerization –>
increase shelf-life and the working time

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

What are pigments?

A

metal oxides pigments to provide different shades and opacities

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

Why are inorganic fillers added?

A

improve the strength, wear resistance and optical
characteristics of the material

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

What are the properties of inorganic fillers?

A
  • decrease polymerisation shrinkage
  • decrease coefficient of thermal expansion
  • decrease water sorption
  • increase viscosity –> decrease wetting
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the filler particle size and loading of ideal composite?

A
  • highly filled
  • very small particles
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

WWhat happens if we decrease filler particle size?

A

increased polishability and wear resistance

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

What happens if filler loading is increased?

A

increase the mechanical
properties

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

What is a coupling agent?

A

used to bind the filler particles to the organic resin matrix

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

What are the advantages of resin composite?

A
  • superior esthetic quality: their refractive index is close to that of tooth structure
  • they are available in different shades to simulate all tooth colors
  • satisfactory physical and mechanical properties (strength, toughness and surface hardness)
  • combined with adhesives they conserve and reinforce tooth structure
  • have low thermal conductivity, don’t transmit thermal shocks to pulp
  • easy to repair
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are the disadvantages of resin composites?

A
  • questionable adaptation to tooth structure
  • high occlusal wear in areas of high occlusal stress
  • hydrolytic Instability in the oral fluids in terms of water sorption and hydrolysis by acids
  • high technique sensitivity as composite insertion is difficult and time-consuming (It needs proper isolation and attention to technique details)
  • lack of anti-cariogenic potential by fluoride releas
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the questionable adaptation found in the composite?

A
  • high polymerization shrinkage which causes the material to pull away from the underlying enamel and dentin
  • poor wettability to tooth structure because of its high viscosity and high surface tension
  • high coefficient of thermal expansion than that of the tooth structure which causes marginal gap formation at the tooth restoration interface
  • these shortcomings in composite cause microleakage around restoration
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are the classifications of resin composite?

A
  • according to size of fillers
  • according to curing mode (technique of polymerisatiion)
  • according to packing technique
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the types of composite according to size of fillers

A
  • macrofilled composite (early composite)
  • microfilled composite
  • hybrid composite
  • nano-hybrid composite
  • nano composites (true nano composite)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are macrofilled composites?

A
  • average particle size 8-10/um and filler loading of 75-80 %wt
  • non-polishable, because during polishing, the weaker organic matrix will abrade more producing a
    rough surface
  • this type of composite is out-dated and not used anymore
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are microfilled composites?

A
  • particle size of 0.02-0.04/um & filler loading is 35-50 %wt
  • polishable, have smooth and lustrous surface, with good wear resistance due to small filler size
    – low mechanical properties due to high resin content
    – used in non-stress bearing areas where esthetics and smoothness of restoration is important as veneers
    – their low modulus of elasticity (flexible material) makes them
    suitable for cervical lesions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What are hybrid composites?

A
  • have combination of colloidal silica microfillers and glass macrofillers
  • this combination allows filler loading up to 80%wt
    – they have good mechanical properties & adequate
    esthetics and good surface characteristics
26
Q

What are nano-hybrid composites?

A
  • newest addition of composite filling materials
    – have nanaofillers range in size from 0.005-0.01/um
    – have superior esthetic and wear characteristics, high polishability,
    and superior handling characteristics.
    – marketed as universal composites
27
Q

What are nano composites?

A
  • its mission was to provide esthetic of microfilled resin composite and
    mechanical properties of hybrid resin composite
  • filler loading was increased using nanoparticle and nanoclusters
28
Q

What are composites classified into according to curing mode?

A
  • chemically polymerised systems
  • light-polymerised system
  • dual polymerised systems
  • heat polymerised systems
29
Q

What do chemically polymerised systems consist of?

A

two-paste system: one paste
contains the activator (aromatic tertiary amine) the other paste contains an initiator (benzoyl peroxide)

30
Q

What do light-polymerised systems consist of?

A

comprise one paste only: the paste
contains photo-sensitive chemical (camphorquinone) which absorbs
visible light to activate the benzoyl peroxide initiator

31
Q

What do dual-polymerised systems consist of?

A
  • combine both versions
  • they start by photochemical reaction and continue by a chemical process
  • mainly used in resin cements
32
Q

What are heat-polymerised systems used for?

A

indirect composite

33
Q

What are the advantages of visible light-cured composite?

A
  • command setting (unlimited working time)
  • no air bubbles as it is one paste (no mixing)
  • improved color stability
  • better control of polymerization shrinkage
34
Q

What are the disadvantages of visble light-cured composite?

A
  • direct prolonged eye exposure to light source can cause retinal damage
  • heat generation from the light source could cause pulpal irritation
35
Q

What is composite classified into according to packing technique?

A
  • incremental packing
  • bulk packing
36
Q

What are the properties of incremental packing?

A
  • used with light-cured composites only.
  • restorations are placed in successive small increments (not more than 2mm)
  • decrease polymerisation shrinkage
37
Q

What are the properties of bulk packing?

A
  • used only with chemical cured composite (historical) as it was applied as one increment
  • it could be used with bulk fill composite that could be packed in 4 mm increment
  • used with light cured composite, in small non deep cavities (not exceed
    2mm)
38
Q

What is composite classified into according to presentation?

A
  • packable composite
  • flowable composite
  • bulk fill resin composite
39
Q

What are the properties of packable composites?

A
  • also named high density or condensable composites
  • they are composites with high filler loading and large particle size that are used for large posterior restorations
  • their packability and lack of stickiness –> tight proximal contacts
  • they also have good fracture resistance
40
Q

What are the disadvantages of packable composites?

A
  • poor adaptation to cavity walls
  • poor wear resistance due to large filler particles
  • opaque and unesthetic for anterior restorations
41
Q

What is flowable composite?

A

low-filled composite with low viscosity

42
Q

What are the advantages of flowable composites?

A
  • increased adaptability
  • increased elasticity
43
Q

What are the disadvantages of flowable composite?

A
  • low mechanical properties as strength & wear
  • high polymerization shrinkage
44
Q

What are the indications of flowable composite?

A

in cervical lesions, in small restorations in non-stress bearing
areas, and as a liner/base under composites to absorb stresses,
also as pit & fissure sealants

45
Q

What are the contraindications of flowable composite?

A

large restorations & in stress-bearing areas

46
Q

What are the properties of bulk fill resin composite?

A
  • it is advanced composite technology allows for directly placed posterior restorations with bulk-fill composite in a single increment (4mm)
  • it may be presented as smooth and creamy consistency that can achieve high marginal adaptation to the floor and walls of the cavity
  • the shrinkage stresses were decreased with decreased postoperative sensitivity, microleakage, and secondary caries.
  • the light-sensitivity technology provides fast curing of 4mm in 10 seconds
47
Q

What are the characteristics of resin composite used for layering technique?

A
  • it is impossible to reproduce the lost tooth structures (enamel & dentin) with single shade of resin composite
  • different shades were introduced to facilitate perfect restoration of tooth shades & all optical properties
  • most of these composites are microfilled or true nano composite
48
Q

What are the types of shades available?

A
  • translucent shades
  • enamel shades
  • dentin shades
  • body shades
  • opaque shades
49
Q

What is translucent hade?

A
  • almost clear
  • for creating an incisal edge and proximal line angles
50
Q

What is enamel shade?

A

similar to enamel in translucency and modify the underlying dentin to obtain the final tooth shade

51
Q

What is dentin shade?

A
  • modify underlying tooth color
  • reduce the transmission of light through the restoration
  • not as opaque as masking agents
52
Q

What is body shade?

A
  • translucency is closer to the enamel shades than to the dentin shades
  • used for single shade restorations (without layering)
53
Q

What are opaque shades (extra white shades)?

A
  • used to mask the dark discolorations before resin composite application
  • if used improperly, it will lighten the shade of the final restoration
54
Q

What are the indications of resin composite?

A
  • can be used in all Classes of cavity preparations whether
    originating from carious or non-carious lesions
  • used in esthetic enhancement procedures: correction of tooth form and contour (peg shape laterals), diastema closure, partial or complete veneer for discolored or defective teeth
  • used as pit and fissure sealant and in preventive resin restorations (PRR)
  • used as foundation or core build-up material under crowns and bridges.
  • used for cementation of indirect esthetic restorations (resin cement)
  • used in repair of restorations
  • periodontal splinting (fixation of teeth)
  • bonding of orthodontic brackets
  • liner/base (flowable commposite)
55
Q

What are the contraindications of resin composite?

A
  • patients with bad oral hygiene and high caries index
  • if the cavity cannot be properly isolated from oral fluids (deep subgingival areas)
  • patients with heavy occlusal stresses (unfavorable occlusion or bruxism)
56
Q

What are the advantages of low molecular weight monomer?

A
  • increase fluidity for material
  • decrease viscosity
  • increase wettability
  • improve mechanical properties
57
Q

What are the disadvantages of low molecular weight monomer?

A
  • increase polymerisation shrinkage
  • increase water sorption as it is more hydrophobic
58
Q

How does hydroquinoe act as an inhibitor?

A

neutralise free radicals

59
Q

Why is there pink composite?

A

for gingiva during gingival recession

60
Q

Hpw does coupling agent work?

A
  • an organo-silicane is used with bi-functional molecule
  • one end forms siloxane bonds (silane coupling agents) with hydroxyl group of silica filler while the other end is capable of copolymerising with monomers of matrix
61
Q

Why is micro-filled composite not used in class 1 and 2?

A

due to stress in posterior teeth during mastication

62
Q

Why is it not aesthetic to have tertiary amine in restorations?

A

it turns cmposite yellow

operative (6 decks)

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