Direct Filling Gold Question And Answers

Direct Filling Gold Short Essays

Question 1. DFG (Direct Filling Gold).

Answer:

DFG (Direct Filling Gold):

Definition:

  • Direct gold is a gold restorative material that is manufactured for compaction directly into prepared cavities

Indications:

  • Class 1 cavities Small carious lesions in pit and fissures of posterior teeth
  • Class 5 carious lesions
  • Class 3 cavities proximal surfaces of anterior teeth
  • Class 2 restoration of small cavitated proximal surfaces of posterior teeth
  • Class 6 Incisal edges or cusp tips
  • A defective margin of cast metal restoration

Contraindications:

  • Veiy large pulp chambers
  • Severely periodontally weakened teeth with questionable prognosis
  • In handicapped patients
  • Root canal-filled teeth

Classification:

1. Foil:

  • Sheet
    • Cohesive
    • Noncohesive
  • Ropes
  • Cylinders
  • Laminated foil
  • Platinized foil

2. Electrolytic precipitate:

  • Mat gold
  • Mat foil
  • Gold calcium alloy

Question 2. Types of gold.

Answer:

Types of gold:

1. Gold Foil Oldest form:

Types:

1. Sheets size 10 x 10 cm

  • Thickness 1.5 micron
  • No.3 weighs 3 gm
  • Too large for use in preparation

2. Gold foil cylinder

  • Uses noncohesive gold
  • Uses % and 1/8 of a sheet of gold

3. Gold pellets

  • Are annealed before the formation
  • Stored in a gold foil box along with a cotton dipped in 18% ammonia

4. Platinized gold foil

  • Platinum content in foil is 15%
  • Increased hardness

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  • Used for restoration of cusp tips and incisal edges

5. Corrugated gold foil.

  • Paper placed between foil gets burnt and charred

4. Laminated gold foil:

  • More resistant to applied forces

2. Crystalline Gold

1. Mat gold

  • Electrolytically precipitated type
  • Used for building up of internal restoration

2. Mat foil

  • No need of veneering the restoration

3. Electralloy

Increased hardness and strength of gold by adding minute quantities as Calcium

Improved handling properties

4. Powdered Gold

  • Size 15 microns
  • Difficult to handle
  • Does not require very sharp line angles and point angles

Question 3. Mat Gold.

Answer:

  • Electrolytically precipitated

Preparation:

  • Sinter pure gold in the oven
  • Heat slightly below its melting point

Result:

  • Spongy, loosely arranged crystalline structure
    • Available in form of strips
    • Can be used plain/sandwiched in gold foil
  • Use: Building up of internal restoration
  • Advantage: Easily compacted
  • Adapted well

Question 4. Condensation of DFG.

Answer:

Condensation of DFG:

Aims:

  • Formation of cohesive mass
  • Adaptation to the preparation margins
  • Prevent voids formation
  • Increases strength and hardness of restoration

Technique:

  • Place the gold piece in the corner of the preparation
  • Start malleting in the center of the mass
  • Condense at 45o to walls and floor for maximum adaptation
  • Next condense at 90° to the previous layer to prevent displacement of already condensed pieces
  • Each time the condenser should overlap the half of previous step for reducing voids formation
  • This is called stepping

Direct Filling Gold Stepping of condenser during condensation of direct gold

Direct Filling Gold Tie Formation

Direct Filling Gold Bamking of the walls

Question 5. Annealing/Degassing.

Answer:

Annealing:

  • It involves the removal of the volatile protective coating present on a pure gold surface
  • Used for noncohesive gold, as a layer of ammonia is present over it to prevent the formation of the oxide layer and contaminate gold

Methods:

1. Using alcohol Flame:

  • Bulk method:
    • Place mass of gold in mica tray and heat over flame up to 650700°C
    • Less time required
    • Risk of overheating
  • In the piece method;
    • Hold small pieces over a blue flame of alcohol and heat until the gold becomes dull red
    • Less wastage
    • Time consuming

2. Electric Annealer:

  • Gold is heated for 10 minutes at 850°F
  • Then cooled for placing in the prepared tooth

Direct Filling Gold Short Answers

Question 1. Preparation of Pure gold foil.

Answer:

Preparation of Pure gold foil:

  • Gold foil are cut into sheets
  • These sheets are separated by papers
  • These are heated together
  • 20 such papers are consist in the book
  • These sheets are cut into different sizes and are available in different weight

Question 2. Properties of DFG (Direct Filling Gold)

Answer:

Properties of DFG (Direct Filling Gold):

  • It is soft, malleable, and ductile
  • It does not get oxidized
  • It is yellowish, metallic in color
  • It get fuses at 1063oC and boils at 2200oC
  • The density of gold is 1919.3 g/cm2
  • Its hardness is 25 BHN
  • Its coefficient of thermal expansion is 14.4 x 106/oC which is more than that of a tooth
  • It is the noblest of all metals
  • It has high thermal conductivity
  • It can be cold welded
  • It results in good marginal integrity

Question 3. Electrically.

Answer:

Electrically:

  • The newest form of DFG

Preparation:

  • Electrolyte it along with the addition of minute quantities of calcium
  • The resultant crystalline structure is sandwiched between two gold foils

Advantages:

  • Improved handling properties
  • Produces the hardest surface
  • Increased strength and hardness

Question 4. Gold Foil.

Answer:

Gold Foil:

Types:

1. Sheets size 10 x 10 cm

  • Thickness 1.5 micron
  • No.3 weighs 3 gm
  • Too large for use in preparation

2. Gold foil cylinder

  • Uses noncohesive gold
  • Uses % and 1/8 of a sheet of gold

3. Gold pellets

  • Are annealed before the formation
  • Stored in a gold foil box along with a cotton dipped in 18% ammonia

4. Platinized gold foil

  • Platinum content in foil is 15%
  • Increased hardness
  • Used for restoration of cusp tips and incisal edges

5. Corrugated gold foil

  • Paper placed between foil gets burnt and charred

6. Laminated gold foil

  • More resistant to applied forces

Direct Filling Gold Viva Voce

  1. All types of DFG except non corrosive gold require degassing before use
  2. Underheating fails to render the gold surface pure
  3. Overheating makes the gold more brittle
  4. Poor resistance form can result in tooth fracture
  5. Improper retention form results in loose restoration
  6. Forces of condensation should be at 45° to the cavity walls and floors
  7. Forces of condensation must be at 90° to previously condensed gold

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