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Resto 3 > Operative materials > Flashcards

Operative materials Flashcards

1
Q

What is the objective of cavity bases? (2)

A
  1. Replace lost tissues.

2. Avoid problems due to the treatment technique and complications from final restoration material behavior

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2
Q

What materials are used for cavity bases? (3)

A
  • GIC
  • eugenol cements, biodentin
  • adhesives
    + composite resins
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3
Q

Whats the principal component of GIC?

A

Polyalkenoic acids

*bond calcium and phosphate of the tooth

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4
Q

GIC and adhesive?

A

not needed because it bonds chemically

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5
Q

What are the main components of GIC?

A
  • Polyalkenoic acids
  • water (50%)
  • tartaric acid
  • glass particles
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6
Q

What is the acid of GIC? (4)

A

Polyalkenoic acids:

- AC polyacrylic, polymaleic acid and itaconic acid

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7
Q

What type of reaction does GIC have?

A

acid-base chemical reaction

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8
Q

What components are part of the glass particles of GIC? (4)

A

it is the BASE

- crystals of Si, Al and F (calcium flouride)

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9
Q

What is tartaric acid in GIC?

A

Setting accelerators

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10
Q

What does the water do in GIC?

A

setting essential

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11
Q

What are the other components of GIC?

A

Radiopacifiers
pigments
resin reinforcers

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12
Q

What is the radiopacer component of GIC?

A

Silver
Zn oxide
OR barium glass

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13
Q

What is the pigment component of GIC?

A

aesthetics

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14
Q

What are the resin reinforcers of GIC?

A

Metals (dissued)

Light & self cured resins

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15
Q

Why are there light and self cured resins in GIC?

A
  • Improve the mechanical and esthetic properties.
  • Protect from moisture and drying: less moisture-sensitive.
  • Facilitate handling: Longer working time
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16
Q

How are GICs classified? (3)

A
  • Conventional
  • Hybrid
  • Compomers
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17
Q

What is the conventional GIC?

A
  • acid base reaction

- mixed with water

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18
Q

What is hybrid GIC? (2)

A
  • 2 independent reaction settings

* GIC with resin - photo or light curing

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19
Q

What are the 2 independent reactions of GIC?

A
  • acid / base (common to all GIC)

- Photo

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20
Q

What is compomer GIC?

A

Mainly resin with GIC added

  • considered resins not cements
  • higher photo resin content
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21
Q

GIC and acid susceptibility?

A
  • conventional GIC
  • predisposed to acid erosion because GIC is inorganic
  • less acid suspectibility in resin-modified GIC
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22
Q

What is conventional GIC used as?

A
  • cement

- provisional restoration

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23
Q

Conventional GIC and occlusal forces?

A

Don’t expose to occlusal forces because it will break

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24
Q

Why are resins added to GIC? (3)

A
  • To achieve less curing time.
  • Less sensitive to handle in the initial setting phase.
  • Get a surface that chemically joins the composite resins.
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25
Q

Photo/self curing resin properties? (3)

A

➢Hema (10%)
➢Setting: two independent reactions
➢The main features of the GIC are not altered

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26
Q

Indications of conventional and resin modified GIC?

A
  • Fissure sealant
  • cavity base
  • cement
  • direct restoration material
  • not on cavities that receive direct occlusal forces
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27
Q

Why do we use conventional/resin modified GIC as a cement? (4)

A
  • good chemical adhesion (good sealing)
  • F release
    (anticariogenic and desensitizing)
  • good viscosity
  • low thickness.
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28
Q

Why do we use conventional/resin modified GIC as a direct restoration material?

A

• Class V cavities with a lack of enamel in the cavity margin
- abfraction (modulus of elasticity similar to dentin).
• To fill areas with undercuts in big restorations, if it is going to hold indirect
restorations*

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29
Q

Why do we use conventional/resin modified GIC as a fissure sealant?

A

Better adhesion to enamel than composite resin

BUT it goes away so use flowable composite instead now

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30
Q

What is the presentation of hybrid GICs?

A

capsules
to spatulate
clickers

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31
Q

Whats the sandwich technqiue?

A

Tooth - GIC - composite

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32
Q

Whats equia fil & equia coat?

A
  • New generation of high strength glass ionomer
  • nano-filler with high F release
  • excellent to replace amalgam and composite class I, II, V
  • in peds or geriatrics
  • not sticky and easy to handle
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33
Q

Zn eugenol cement cavity base properties?

A
  • antiseptic
  • pulp irritant
  • not used because not compatible with composite resin
  • poor resistance
  • not aeshtetic
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34
Q

Why is zn eugenol not comptaible with composite resins?

A

Eugenol inhibits polymerization of resin materials

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35
Q

What is Zn eugenol used for?

A

Temporary fillings

stepwise caries removal

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36
Q

What is stepwise caries removal procedure?

A
  • Clean almost all the caries but leave a bit
  • Cover with CaOH, then obturate with zinc eugenol cement
  • after 8 weeks - removal + caries removal
    • Didnt need to clean remaining caries as deep as with one step.
  • the odontoblasts protect the pulp from the injury
  • this is the only time we use zinc eugenol in restorative
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37
Q

Biodentine composition?

A

Calcium silicate based product:

  • tricalcium silicate: regulates setting
  • calcium carbonate: filler
  • zirconium dioxide: radiopacity
  • calcium chloride: accelerator
  • water soluble polymer: reduces viscosity
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38
Q

Biodentine uses? (4)

A
  • indirect pulp capping
  • direct pulp capping
  • direct restorations in deep cavities
  • inlay/onlay
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39
Q

Biodentine properties (5)

A
  • has to be covered by composite or indirect restoration
  • good to replace dentin
  • capsule and liquid. put liquid in capsule (powder)
  • can be put directly on pulp exposure.
  • wait 12 minutes thats the time it takes to set
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40
Q

Biodentine in normal cavity?

A

to replace dentin and then covered by composite

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41
Q

Biodentine in indirect restoration?

A

base on the floor (build up) then take impression for indirect

42
Q

Biodentine in pulp exposure?

A

put directly on pulp

43
Q

Cavity base with adhesive and RC function (2)

A
  • seal (adhesive)

- give shape to floor of cavity (RC)

44
Q

Cavity base with adhesive +RC? (2)

A
  • used directly over deep
    cavities : Self etch adhesives to prevent pulp exposure
    or creating an altered hybrid layer
    (hybridoide layer).

-Place the
RC, compomer or reinforced GIC as
artificial dentin on top

45
Q

What is the hybridiodie layer? (2)

A
  • demineralized area (orthophosphoric acid) that is not penetrated
    by the adhesive .
  • Brittle :pressure differences in the pulp = postoperative pain
46
Q

Why do we use self etch in cavity base (Adhesion +RC)?

A

The problem with using etch is if its left too long, it creates deeper microretentions than the adhesive can penetrate.

47
Q

What is a compomer?

A

Composite resin containing small amounts of GIC

48
Q

What is a compomer composed of?

A

➢ Glass particles (Filler particles similar to the powder of GIC
calcium-fluoro-alumino-silicate glass)
➢Composite particles (SI , Sr, Ba sulfate )
➢Polyalkenoic acid (not in aqueous solution ) modified by Bis-GMA and UDMA
➢Pigments to enhance the aesthetic

49
Q

Disadvantages of using compomers?

A
  • Etching and bonding is mandatory.
  • Less wear resistant than conventional composite.
  • Insignificant release of fluoride.
50
Q

Compomer indications?

A
  • same as composite
  • Direct restoration material.
  • To build up a core in fixed prosthodontics.
51
Q

Compomer technique? (2)

A
  • Same as composite resins (etch and adhesive).

- Only light curing

52
Q

Composition of composite resins? (7)

A
  1. Resin matrix(organic content)
  2. Fillers (inorganic part)
  3. Coupling agents (Silane- bonds glass fillers to matrix).
  4. Activation systems.
  5. Pigments.
  6. Radiopacifiers.
  7. Optical modifiers
53
Q

What does the composite resin matrix consist of?

A
  • mostly Bis-GMA

* the monomer is diluted with a varying range of other monomers of lower molecular weight.

54
Q

Bis-GMA in composite resin matrix?

A
  • viscous alone

- mixed in different combinations with short chain monomers (ex. TEGDMA)

55
Q

Describe bisGMAs chemical structure

A

aromatic core and 2 reactive links where polymerization occurs

56
Q

Composite resins: the higher the molecular weight…

A

the higher the viscosity ,

difficult to manipulate and incorporate inorganic filler

57
Q

Composite resins: the lower the molecular weight…

A

the more polymerization shrinkage

58
Q

Composite resins organic matrix: which monomers have higher molecular weight? properties?

A

Bis-GMA + UDMA

  • contraction 5-6%
  • worse handling
  • difficult inorganic filler addition
59
Q

Which monomers are low molecular weight? (5)

A
  • viscosity regulators, dilutants
  • BIS-MA
  • EDGMA
  • TEGDMA
  • MMA (most commonly used)
  • D3MA (most commonly used)
  • most composite resins mix methacrylate monomers
60
Q

What is the purpose of fillers in composite resin? (5)

A
  • Responsible for resin composites final characteristics.
  • Mechanical properties
  • Polymerization shrinkage
  • Surface roughness
  • Optical properties
61
Q

The filler content of a composite is sometimes determined by…

A

the shape of the

filler

62
Q

Composite resins: What happens if we have high % of fillers ? (2)

A
  • Better mechanical properties and reduced
    polymerization shrinkage.
  • Smaller particles : > filler content.
63
Q

Composite resin: viscosity depends on…

A
  • fluidity of the monomer

- % of filler incorporated

64
Q

Composite resin: If the filler content increases,

> viscosity of the mixture because.. (2)

A
  1. > friction between particles

2. > particle surface to be wetted by the resin

65
Q

Composite resin: Surface roughness or polishing is better if…

A

> Filler

< Particles size

66
Q

How much filler is in flowable composite ?

A

More matrix than filler = more fluid

67
Q

What are the different filler particles?

A
  • Glass silica: macroparticle
  • Non-glass silica particle: microparticle
  • Colloidal silica and ziconium oxide: nanoparticle
68
Q

Describe macroparticle fillers: (3)

A
  • glass silica
  • conventional composite resins or macro-particle ( 10-80 microns)
  • nowadays triturated (1-10 microns)
69
Q

Describe microparticle fillers: (3)

A
  • nonglass silica
  • less abrasive
  • 0.01-1 micron (avg 0.04)
70
Q

Describe nanoparticle fillers: (3)

A
  • colloidal silica (20nm) and zironcium oxide (4-10nm)

- joined: nano-clusters (0.6-20nm) allows more filler content

71
Q

Which composite resin filler isnt used anymore? why (4)

A
  • glass silica
  • too strong would wear down organic matrix and expose filler
  • would wear on antagonist tooth
  • eventually detach from matrix and create grooves in obturation
72
Q

When do we use microparticle? (2)

A
  • Used to restore anterior tooth (class IV)

- Last layer of the buccal wall of the tooth

73
Q

What is the purpose of silane coupling agents in RC?

A

to improve adhesion of the resin to filler surfaces

74
Q

What are the components of systems initiating polymerization in RC? (3)

A

Activation systems-

  • heat (benzoyl peroxide),
  • chemical (benzoyl peroxide and aromatic
    amine)
  • photochemical (camphoroquinone and tertiary amine)
75
Q

What are the additives in RC? (4)

A
  • Stabilizers
  • Dyes
  • Optical modifiers/Pigments : provide fluorescence and opalescence
  • Radiopaque fillers
76
Q

What are the different ways to classify RC? (5)

A
  1. Fillers size
  2. Viscosity
  3. Polymerization system
  4. Aesthetic properties
  5. Indications
77
Q

What are the different ways to classify RC by filler size? (4)

A
  1. Macroparticle: Small particle: 1 – 10µ. 70-80% inorganic filler
    weight.
  2. Microparticle: average size 0,04 µ. Use: anterior teeth
    • Homogeneous 30-40% microparticles SiO2: viscous, poor resistance, good polishing
    • Heterogeneous : micro particle + agglomerated pre-polymerized micro particles mixed
    with resin and triturated: higher filler content composite (60-80%) with better properties.
  3. Hybrid
  4. Nanoparticle: Isolated particles 5 -20 nm. Cluster
    (nanoparticles aglglomarated, 1µ),low viscosity, high translucency
78
Q

Describe hybrid composites:

A
  • Filler particles are a mix of sizes and shapes: particles max 5µ + microfilled particles between them.
  • 80% inorganic filler weight
  • Universal composites: Used in post and ant
79
Q

Almost all hybrid composites on the market now are …

A

Nanohybrid

- include nanparticles and nano clusters

80
Q

Describe nanohybrid resins: (3)

A

• By reducing the size of the particles and increasing the total surface to be
wet by the resin it should increase viscosity but it doesn’t, because
nanoparticles do not behave like a solid they behave more like a
liquid.
• To increase the amount of fillers, the manufacturers form agglomeration
of nanoparticles or nanoclusters (having a size of about 1 micron), to give viscosity, color, opacity and radiopacity.
* we can fit more filler and not affect viscosity negatively
• Nanofillers can be incorporated into other composites improving
their properties (resistance to tensile strength, abrasion, marginal stability and provides a very good polishing).

81
Q

Describe nanohybrid composites:

A

• Universal composites: superior esthetic and wear characteristics,
high polish-ability, and superior handling characteristics.

• They correspond to most composite resins current’s presentation and they are an evolution of the microhybrid

82
Q

Hows are RC classified by viscosity?

A 
1. Flowable: Low viscosity. Indications:
• Class V or I –small-
• As a base in big cavities.
• Bulkfill: nanofilled, low contraction monomers. 4mm polymerization
(translucency).
  1. Conventional: Medium viscosity.
  2. Packable: High viscosity. Stiffer, thicker feel. Disused
83
Q

How are RC classified by polymerization system?

A
  1. Self cured: Chemical initiation. Benzoyl peroxide
  2. Light cured: - Photoinitiators: Camphorquinone
    (427-491 nm)
    Fenilpropanodione 430 nm.
  3. Dual cure: Chemical initiation. + light cured.
84
Q

What factors influence polymerization? (8)

A
  • time
  • composite color
  • temp
  • thickness (<2mm)
  • filler type
  • distance between light and composite
  • quality of light
  • contraction - depends on organic phase
85
Q

What is conversion degree? (2)

A
  • % of double bonds that have reacted
  • best case = 70%

*monomers reacted forming polymers

86
Q

Higher degree of conversion means…

A

Clinical behaviour is better

87
Q

How is RC classified by aesthetic properties?

A
  1. By translucency
    • Very translucent: clear composite/almost transparent: Incisal edges.
    • Translucent: As enamel.
    • Medium opacity. Composite body as dentin.
    • Opaque: As dentin.
    • Opaquers: To hide defects.
  2. By its optical effect: Fluorescence or
    opalescence
  3. By its use in the stratification technique:
    • Dentin, enamel, effects, opaquers, dyes
88
Q

Whats are tints in RC? (4)

A
  • resins with intense colarants to increase final aesthetics of restoration
  • objective: reproduce morphological or chromatic characterics (white spots, lines, cracks)
  • minimal use - small quantities at subsurface location (because not as resistant)

*always as second last later of composite

89
Q

Clinical considerations that influence in the

selection of a composite?

A

• Location of the cavity
1. Occlusal , interpoximal, classes IV , VI classes . : Composite with
high inorganic filler content.
2. Aesthetic anterior restorations : Good polishing , suitable opacity
and fluorescence (nanohybrids or nanoparticle).
3. Cervical restorations: good polishing and flexure.
*class V/cervical use flowable then cover with conventional/hybrid

• Teeth colour
Other materials:
-Opacifiers
- Tints

90
Q

What is the main property of new resin composites?

A

low shrinkage direct composites

91
Q

What are the new resins? (3)

A
  • silorane
  • organically modiifed ceramic
  • bulk fill technique
92
Q

Describe silorane

A

• Reaction of siloxane and oxirane molecules. Patented by 3M - ESPE.
• Stress compensation achieved by opening/expanding
oxirane rings during polymerization instead of
contracting

• Requires specific adhesive bonding resin with LS Bond (3M
ESPE).
*Not compatible with other resins.
• The volumetric shrinkage is 1.7%.

  • Most conventional composites shrink 3%-5% .
  • 40-50% less volumetric changes than conventional ones.
93
Q

Silorane mechanism (3)

A

Starts with the opening of the ring systems.

  • Gains space and counteracts the loss of volume which occurs when the chemical bonds are formed.
  • Yields a reduced volumetric shrinkage.
94
Q

Describe organically modified resin matrix with ceramic: (3)

A

• Consists of organic (polymers) and inorganic (ceramic glasses)
network = advantages of both.
• Polymerization shrinkage decreases.
• Conflicting studies according to wear resistance,
adaptation and adhesion forces

95
Q

What are the different organically modified resin matrix with ceramic?

A

CeramX (dentsply)
- low shrinkage through
pre-polymerized Ormocer matrix.

Admira (Voco)

  • indicated for all resto classes
  • suitable for composite inlays
  • packable, non-sticky,
  • high polishability.
  • Ideal in allergy prone patients with its low monomer release.
96
Q

What is organically modified resin matrix with ceramic also called?

A

Ormocers (ORganically MOdifed CERamic)

97
Q

What must be considered in bulk-fill technique?

A

1) Polymerization shrinkage.
2) Polymerization depth and light penetration.
3) Prolonged working time.
4) Ensure quick & easy access to the light.

98
Q

What is in the bulkfill composite? (3)

A
  • photoiniciator ivocerin: - allows 4mm layers+ short polymerization time (Added to lucerna and camforquinone)
  • sensitivity light filter: allows long working time for correct handling
  • stress reliever: less shrinkage
99
Q

Describe bulkfill compsoite:

A

• Allows placement of posterior restorations in single increment.
• The stress reliever increases marginal integrity and decreases polymerization shrinkage
• The light-sensitivity filter provides longer
working time (won’t polymerize quickly under ambient light, it is
easier to place than conventional composite )
• Manufactured with a polymerization booster for fast curing of up to 4 mm in 10 seconds.

100
Q

What are the “other composites”?

A

Fiber reinforced composite FRC

101
Q

Describe FRC (6)

A

• Combination of conventional dental composite and glass
fibers: improve level of strength, flexibility., > resistance to
occlusal load.
• 1-2 mm glass fiber silane-coated to join the resin matrix.
• Contraction varies depending on fiber direction - supposed to lay parallel to surface when the material is
condensed inside the cavity.
• Used in block as dentin replacement, but must be
covered by conventional because behave badly on surface.
• Good resistance to occlusal forces (when covered).
• Improvement in fracture resistance of the teeth and restorations..

102
Q

FRC brand?

A

GC everX posterior

Resto 3 (6 decks)

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