Filling Materials

Filling Materials

Requirements
1. Aesthetic
2. Adhesive bond with tooth
3. Radiopaque
4. Decreased thermal conductivity & diffusivity
  1. Protect pulp
5. Similar coefficient of thermal expansion to enamel & dentine
6. Long WT & short ST
7. Mechanical properties
  1. Strong (less creep)
  2. Tough
  3. Reduced wear
  4. Hard
Amalgam
1. Setting reaction = y + Hg --> y1 + y2 + y + Hg
2. Composition
  1. Powder = Silver, Tin, Copper, Zinc
  2. Liquid = Mercury
3. Advantages
  1. Least moisture sensitive
  2. Most durable
4. Disadvantages
  1. Brittle in thin sections
  2. Thermal diffusivity > tooth tissue
    1. Need cavity liner for deep cavity e.g. setting CaOH
  3. Creep -> ditching
  4. Galvanic corrosion
  5. No tooth adhesion
    1. Needs mechanical retention added to cavity prep -> more destructive
Composite
1. Composition
  1. Resin
    1. Bis-GMA
    2. Large vol. -> reduces shrinkage
  2. Filler
    1. Higher filler content -> reduced shrinkage & thermal expansion + increased mechanical properties
    2. Radiopaque
  3. Coupling agent
    1. Joins filler to polymer
    2. Silane coupling agent
    3. Increases mechanical properties
2. Types
  1. Handling characteristics
    1. Packable
    2. Flowable
      1. Reduced filler content
        Lower viscosity
      2. Use
        Fissure sealant
        Cavity liner
        Non-carious cavity
  2. Activation
    1. Chemical
      1. 2 pastes - requires mixing
    2. Light
      1. 1 paste + blue light source
      2. Depth of cure
      3. Unlimited WT (command set)
    3. Dual
      1. Both light & chemical
3. Setting reaction = exothermic free-radical polymerisation
4. Advantages
  1. Tooth coloured
  2. Durable
  3. Adhesion to tooth with bond
5. Disadvantages
  1. Shrinkage
    1. Debonding in cavity
    2. Post-op sensitivity
    3. Marginal staining & microleakage -> secondary caries
    4. Enamel microcracks
  2. Most moisture sensitive
GIC
1. Setting reaction = Acid-base
  1. Dissolution, gelation, hardening
2. Composition
  1. Powder = Sodium aluminosilicate glass
    1. Contains Fluoride
  2. Liquid = Acrylic/Maleic acid
3. Use
  1. Cervical restorations (poor moisture control)
  2. Cavity liner
  3. (luting cement - different material)
4. Advantages
  1. Adhesion to tooth
  2. Radiopaque
  3. Similar thermal properties to dentine
  4. Slightly moisture sensitive (1st hour)
  5. Fluoride release
5. Disadvantages
  1. Brittle/reduced flexural strength
  2. Dissolves in acid
  3. Least durable

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	Criado por sanna pathy quase 5 anos atrás