Resin-based restorative materials Flashcards

1
Q

What is the most used restorative material?

A

composite

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2
Q

What is organic resin matrix disperesed by?

A

inorganic fillers bound to the resin by a silane coupling agent and an initiator-accelerator system

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3
Q

What are the different resin matrixes?

A
  • Bis-GMA
  • UDMA
  • TEGDMA
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4
Q

What are the benefits of filler particles?

A
  • Reinforcement of resin matrix
  • DECREASED polymerization shrinkage
  • DECREASED thermal expansion and contraction
  • Viscosity control
  • DECREASED water sorption
  • INCREASED radiopacity
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5
Q

What in the filler increases the radiopacity?

A

Barium
Strontium
Zirconium

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6
Q

________ filler amount reduces the thermal expansion and contraction coefficients

A

Higher

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7
Q

The reduced shrinkage is proportional to the filler ________

A

volume

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8
Q

What is the coupling agent?

A

silane

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9
Q

The interfacial bridge forms between what?

A

the resin matrix and the filler

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10
Q

What is the point of the coupling agent/interfacial bridge?

A

✓ Better stress distribution between resin matrix and filler particles
✓ Improvesthe mechanical properties
✓ Decreased watersorption along filler-resin interface

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11
Q

Composites require that monomers to coverted into

A

polymers

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12
Q

What triggers the composite convertion from monomers to polymers?

A

free radicals

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13
Q

What is the activator for chemical/self-cure composite?

A

tertiary amine

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14
Q

What is the initiator for chemical/self-cure composite?

A

Benzoyl peroxide

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15
Q

What is the reaction for a chemical/self-cure composite?

A
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16
Q

What is the activator for light-cured composite?

A

blue light (465 nm)

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17
Q

What is the initator for light-cured composite?

A
  • camphoroquinone (photosensitizer)
  • DMAEMA (amine)
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18
Q

What are the characteristics of regular (conventional/packable) composite?

A
  • 80-85% filler
  • many applications, versatile, laying technique, more esthetic
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19
Q

What are the characteristics of flowable composite?

A
  • 40-60% filler
  • polymerization shrinkage
  • under regular comp class II
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20
Q

What are the three classification by handling characteristics?

A
  • regular
  • flowable
  • bulk fill
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21
Q

What are the characteristics of bulk fill composite?

A

✓ Developed to enable restoration in single increment built up to 4-5 mm
✓ Increased depth of cure
✓ Reduced polymerization shrinkage stress
✓ Improved adaptation to the surface of the cavity
✓ Simplified placement technique compared to regular composites (incremental)

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22
Q

How do bulk fill composites achieve a depth of cure (polymerization)?

A
  • Reduced filler amount
  • Increased filler particle size
  • Alternative photoinitiators
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23
Q

How do bulk fill composites achieve modulate the polymerization reaction?

A
  • Altered filler particles
  • Presence of stress-relieving monomer
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24
Q

What are the filler particles for bulk fill composites like?

A
  • Lower amount of filler particles
  • Pre-polymerized filler particles (similarly to microparticules comp)
  • Low elastic modulus = help to absorb stresses
  • Added larger filler size particles
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25
Q

What are the monomers for bulk fill composites?

A
  • UDMA
  • Modified UDMA (adding aromatic groups)
  • Fragmentation dimethacrylate monomers
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26
Q

What is the typical path of polymerization of methacrylate?

A
  • pre-gel phase (elastic deformation)
  • gel phase (converting to solid)
  • solid (polymerization shrinkage)
27
Q

What is flowable bulk fill?

A
  • Flowable consistency
  • Lower elastic modulus and reduced wear resistance (mechanical properties)
  • Base for regular composites as the occlusal increment
  • Dentin replacement only
  • Better adaptation on the surfaces of the cavity
28
Q

What is full body bulk fill?

A
  • Suitable wear resistance (better mechanical properties)
  • Replace dentin and enamel
  • Possibility of sculpture
  • Single increment (up to 4-5 mm)
29
Q

Where are the clinical applications of bulk fill composite?

A
  • posterior restorations (class I and II)
  • some specific class III cases
30
Q

What is the process for bulk-fill flow?

A
  1. Filling the cavity (~2 mm to regular comp.)
  2. Wait the flowability of the material
  3. Light-cure
  4. Place and sculpt using regular composites
  5. Light cure
  6. Finishing
  7. Polishing
31
Q

What is a sonic activated bulk fill?

A
  • Rheological modifiers react to the sonic energy applied during placement
  • Cavity adaptation keeping the mechanical properties
32
Q

What is the dual cure bulk fill?

A
  • Dual cure system: chemical (two pastes – automix) and light-cure
  • Single increment (class I and II)
33
Q

Why is finishing and polishing bulk fill composites good?

A

*Decrease the coefficient of friction = reduced rate of wear
*Less bacterial adhesion = less marginal leakage = less possibility of secondary caries
* Color stability = reduce staining (body and marginal)

34
Q

Majority of contouring and finishing of a bulk fill composite should be completed…

A

PRIOR TO LIGHT CURING

35
Q

What are the advantages of bulk fill composite?

A
  • Simplification of the restorative technique
  • Reduced chair time
  • Better flowability = cavity surface adaptation
  • Suitable mechanical properties
  • Reduced polymerization shrinkage stress
36
Q

What are the disadvantages of bulk fill composite?

A
  • Overall, bulk fill are more translucent than regular composites
  • Indicated for posterior restorations
  • Cannot mimic the natural layering of tooth
37
Q

What is a resin-modified glass ionomer (RMGI)?

A

Acid- base, self-adhesive materials, combining fluoro-aluminosilicate glass powder and polyacrylic acid liquid.

38
Q

What are the fluoride properties of resin-modified glass ionomer (RMGI)?

A

Fluoride recharging when exposed to oral environment, “theoretically” indicating their use in patients with high caries risk (minimal esthetic demand)

39
Q

What is the reaction for resin-modified glass ionomer (RMGI)?

A
  1. Ionization of polyacrylic acid in water
  2. Light cure
  3. Initial setting (gelation; salt bridge formation)
  4. Light cure
  5. Final setting
  6. Light cure
  7. Maturation
40
Q

What is the triple cure system for RMGI?

A

Acid-base reaction
+
Light cure (free radicals by light activation)
+
Free-radical by chemical activation
✓ HEMA redox (catalysts)

41
Q

What are the properties of RMGI?

A

✓ Fluoride release and recharge
- Interact with aggregation of biofilm
- Increase release in acidic situations
-Increase the pH
✓Bioactive / Biointeractivity
- Release of Na, PO ions, SiO
✓ Improved working and setting times (compared to conventional GIs)
✓ Mechanical properties
- Low cohesive strength
- Limited strength and wear resistance
- Lower to CR and higher to conventional GIs
✓ Esthetic properties
- Lower to CR and higher to conventional GIs

42
Q

What are the applications of resin-modified glass ionomer (RMGI)?

A
  • Liner material
  • Base material (under amalgam, gold, ceramic, and composite restorations)
  • Low-stress areas (not typical for Class I, II or IV rest.)
  • Where caries is a concern
  • Root-surface caries lesions (primary indication)
  • Slot like Class II or III cervical locations (not proximal contact)
  • Non-carious cervical lesions Class V (if esthetic is not critical)
43
Q

What are noninvasive resin infiltrants?

A

microinvasive surgery

  • Microinvasive: barriers to prevent further dissolution of enamel by acids from cariogenic bacteria
44
Q

What do you do use resin infiltrants on?

A

✓ Pre-eruptive enamel defects:
Molar-Incisor
Hypomineralization (MIH)
Fluorosis
Post-traumatic hypomineralization
✓ White spot lesions
✓ Proximal noncavitated enamel lesions

45
Q

What causes the visual effect in white spot lesions?

A

Differences between refractive index (RI) in sound and white spot lesion in enamel (WSL)

46
Q

What are the objectives of resin infiltration technique?

A

✓ Replacing air into the hollow spaces in WSL with a low-viscosity light-cured resin with a RI (1.52) similar to that of hydroxyapatite
✓ To mask the WSL by preventing the light scattering inside the WSL.

47
Q

What are the steps of resin infiltration technique?

A
  1. Acid etching (15% HCl) Create “access” to the porous areas of the enamel through corrosion to allow resin penetration
  2. Drying the surface (alcohol) Removing water, allowing the resin infiltration
  3. Resin infiltration To replace the air by resin into the porous structure
  4. Light cure the resin
48
Q

What layer of the tooth has resin infiltration been demonstrated to be effective?

A

into 1/3 of the dentin

49
Q

What are the pieces for resin infiltration?

A
  • Etchant (Icon-Etch; DMG): 15% hydrochloric acid, water, pyrogenic silica, surfactant, pigment
  • Drier (Icon-Dry; DMG): ethanol
  • Resin infiltrant (Icon-Infiltrant; DMG): TEGDMA-based resin, initiators and stabilizers
50
Q

____________ is the most prevalent disease in the world

A

Dental caries

51
Q

_____________________ foremost reason for resin-based restoration failure and life span reduction

A

Secondary caries (recurrent caries)

52
Q

Where are the areas with the highest prevalence for recurrent caries?

A

Gingival margin in Class II and V (plaque accumulation and deficient adaptation of restorative material)

53
Q

What is the current dental restorative perspective about bioactivity?

A

anticaries approaches at the material level

54
Q

What are the roles of the combinatory/multimodal bioactive materials?

A
  • antimicrobial
  • tissue regeneration
  • remineralization
  • enhanced bioactivity
55
Q

What are some commercially available bioactive adhesive materials?

A

Clearfil SE Protect Bond (Kuraray) – Adhesive system
*MDP/MDP-B (monomer)
*Bactericidal mechanism
*Fluor release

56
Q

What are some commercially available bioactive restorative materials?

A
  • Activa (Pulpdent)
  • Cention N (Ivoclar Vivadent)
  • Re-gen (Vista Apex)
  • Surefil one (Dentsply Sirona)
57
Q

What does activa (pulpdent) do?

A

✓ Different shades
✓ Ionic Resin technology
✓ Preservation of the pulp vitality
✓ Release calcium, phosphate and fluoride

58
Q

What does cention N (ivoclar vivadent) do?

A

✓ Different shades, light-curable or not, used in association with adhesive systems
✓ Alkasite material
✓ Fillers: barium aluminum silicate glass, ytterbium trifluoride, isofiller, calcium barium aluminum fluorosilicate glass
✓ Higher fluoride release and mechanical properties compared to RMGIs (in some studies)
✓ Several studies IN VITRO

59
Q

What is re-gen (vista apex)?

A

✓ Flowable composite liner
✓ Bulk fill

60
Q

What is surefill one (dentsply sirona)?

A

✓ Self-Adhesive
✓ Bulk fill Composite Hybrid
✓ Dual-Cure Activators

61
Q

What are teh overall characteristics of commercially available bioactive restorative materials?

A

✓ Characteristics between GIs and composite resin (CRs)
✓ Higher mechanical properties than GIs
✓ Lower properties compared to CRs
✓ Release calcium, phosphate and fluoride
✓ Same indications of RMGIs
✓ Long-term efficacy and bond strength require further investigations
✓ Limited evidence in terms of clinical effectiveness

62
Q

Bioactive materials are designed to elicit a desired what kind of response?

A

therapeutic or
beneficial response

63
Q

What does the term bioactive mean?

A

indiscriminately applied to include all simple chemistry, and most effects are indirect results from biological defensive response