DIRECT FILLING GOLD
Dr. Zameer pasha
Lecturer, college of dentistry
AlZulfi, Majma’ah University.
OBJECTIVES

General principles for cavity preparation

Degassing (desorbing)

Compaction

General principles for restoration
GENERAL PRINCIPLES FOR CAVITY
PREPARATION FOR DFG

OUTLINE FORM ------The outline should be smooth and designed to be
esthetically pleasing.
RESISTANCE FORM
flat pulpal
floors perpendicular
to the occlusal forces.
Walls must be
smooth and flat.
Enamel walls
must be supported by
sound dentin.
RETENTION FORM
Parallel or slight
occlusal convergence
of the facial
&
lingual walls.
Sharp internal line
angles resist the
movement of the
restoration.
CONVENIENCE FORM
Convenience form for direct gold cavity
preparation requires suitable access and a dry
field.
 Width of cavity preparation should be minimal.
Separators may be used to provide convenience
access for class III cavity preparation.
 Sharp internal line and point angles in dentin
serve as convenient starting points for
compacting of direct gold restoration.
 Removing remaining caries. Finishing cavity
walls, debridement and pulp protection.

FLAME DESORPTION / DEGASSING








Fuel- alcohol or gas.
Heating each piece directly in the
open flame
Time 5 – 20 min.
Alcohol– pure methanol or ethanol
without colorants or additives.
Advantages—
Ability to select piece of gold of desired
size.
Less exposure to contamination
between degassing and use.
Less damage to oversintering.
DEGASSING
UNDERHEATING


Incomplete cohesion.
Pitting and flaking of
the surface.
OVERHEATING
Oversintering and
possibly
contamination from
tray, instruments or
flame.
 Incomplete cohesion
 Embrittlement
 Poor compaction

COMPACTION



Hand mallet.
Pneumatic vibratory
condensers.
Electrically driven
condensers.
CONDENSERS



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Conventional– single
pyramid shaped face
Current instrument- series
of small pyramidal
serrations on the face.
Serrations- exert lateral
forces on their inclines in
addition to providing direct
compressive forces.
Cut through the outer layers
to allow air trapped below
surface to escape.
CONDENSERS


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Size
The lower limit is based on possible penetration
by points of smaller size, which cause holes in the
metal rather than weld it.
0.5 mm and 1 mm.
PRESSURE APPLICATION

Conventional--- mallet

Recent--- by hand.

Mechanical gold foil condensers—

Consists of points that are activated by light blows
that are repeated with frequency that ranges from
360 to 3600 per minutes.
Vibrations can be produced either pneumatically or
electrically.
 Advantages--- greater comfort to patient and rapid.

DENSITY
Direct gold restoration is characterized by an
uniform density.
 The greatest strength is in the most dense area
and the weakest part is the porous area, where
layers or crystals are not closely packed.

Voids on the restoration surface increase the
susceptibility to corrosion and plaque deposition.
 Voids on the restoration tooth interface may
cause gross leakage and secondary caries
development.

DENSITY
Density of compacted gold restoration is
influenced by size and shape of condenser face.
 Dimensions of prepared cavity.


Dynamics of the compacting system and skill of
the operator.
GENERAL PRINCIPLES FOR DIRECT
FILLING GOLD RESTORATION


1. Build up of
restoration.
A) Tie formationthis involves
connecting two
opposing point angles or
starting points filled
with gold with a
transverse bar of gold.
This “tie” forms the
foundation for any
restoration in direct
gold.
GENERAL PRINCIPLES FOR DIRECT FILLING GOLD
RESTORATION


B) Banking of the walls:
This consists of
covering each wall from its
floor or axial wall to the
cavosurface margin with
the direct gold material.
Banking should be done
simultaneously on the
surrounding walls of the
preparation.
C) Shoulder preparation:
This consists of
connecting two opposing
walls with the direct gold
material to completely fill
up the restoration.

2. Surface hardening of the restoration
The rectangular condenser is used with the
highest possible condensation pressure in all
directions on the surface of the restoration to
strain harden the surface gold.


3. Burnishing
This is done with a suitable burnisher moving
from the gold to the tooth surface. This enhances
the surface hardening and also produces good
marginal adaptation of the gold.
4. Margination:
This step uses sharp gold knives to remove excess
gold from the surface to the tooth.
5. burnishing:
It is important to burnish the surface of gold
restoration after margination so as to eliminate
marginal discripencies and to strain harden the
surface.
 6. Contouring :
This step uses knives, files or finishing burs to
create the proper occlusal anatomy.
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
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7. finishing and polishing :
Direct gold restorations require very little
finishing if the previous steps are properly done.
It can be done by using tin oxide powder on soft
bristle brushes or rubber cups.
8. final burnishing:
This is done after polishing to make the surface
of the restoration smooth and free from voids.
CONCLUSION
The technique skill of the dentist
is of paramount importance to
the success of the direct gold
restorations.
A direct gold restoration of poor
quality can prove to be one of
the most inferior of all clinical
restoration.
REFERENCES
Philip’s Science of dental materials 11th edition by
Kenneth J. Anusavic