This document discusses the history and properties of direct gold fillings. It describes how gold has been used in dentistry since antiquity due to its biocompatibility, corrosion resistance and ability to be welded. Different types of direct gold such as foil, cylinders and powder are introduced. The document outlines the procedures for annealing, compacting and placing direct gold fillings to produce restorations with increased strength, hardness and density compared to pure gold.
One of the oldest filling material among all restorative materials available. Nobel metal filling, which do not undergo Tarnish & Corrosion & having good Biocompatibility.
Classification
foil, electrolytic precipitate & powder gold.
cohesive &non-cohesive form
manipulation
annealing / degassing
Compaction
indication
contraindicatioin
advantage
disadvantages.
direct filling gold... material aspect, types, condensation, cavity design, modifications. detaied seminar for post gradutes.... any doubts or suggestions contact dr.mb@hotmail.com
One of the oldest filling material among all restorative materials available. Nobel metal filling, which do not undergo Tarnish & Corrosion & having good Biocompatibility.
Classification
foil, electrolytic precipitate & powder gold.
cohesive &non-cohesive form
manipulation
annealing / degassing
Compaction
indication
contraindicatioin
advantage
disadvantages.
direct filling gold... material aspect, types, condensation, cavity design, modifications. detaied seminar for post gradutes.... any doubts or suggestions contact dr.mb@hotmail.com
Direct filling gold, explained with Limited matter moreover I have included all the images. if you go through a standard textbook and referred to this PPT it will help you so much I hope It helps you
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The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.
Direct filling gold, explained with Limited matter moreover I have included all the images. if you go through a standard textbook and referred to this PPT it will help you so much I hope It helps you
Indian Dental Academy: will be one of the most relevant and exciting training center with best faculty and flexible training programs for dental professionals who wish to advance in their dental practice,Offers certified courses in Dental implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic Dentistry, Periodontics and General Dentistry.
Indian Dental Academy: will be one of the most relevant and exciting training center with best faculty and flexible training programs for dental professionals who wish to advance in their dental practice,Offers certified courses in Dental implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic Dentistry, Periodontics and General Dentistry.
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
dental Investment materials/ orthodontic course by indian dental academyIndian dental academy
Indian Dental Academy: will be one of the most relevant and exciting training center with best faculty and flexible training programs for dental professionals who wish to advance in their dental practice,Offers certified courses in Dental implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic Dentistry, Periodontics and General Dentistry.
Metals in dentistry /certified fixed orthodontic courses by Indian dental aca...Indian dental academy
Dental Courses by Indian Dental Academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.
Direct Filling Gold is the oldest filling material that is still being used in restorative dentistry. The vision to utilize this noble metal for the replacement of lost tooth structure stemmed from the perfect harmony of its biological and mechanical properties, excluding esthetics. Direct gold restorations exhibit excellent marginal integrity and biocompatibility in the oral environment.
History of Direct filling gold
Properties of gold
Indications, contraindications, advantages and disadvantages of direct filling gold, cohesive semi cohesive and non - cohesive gold, types of direct filling gold, Degassing/ Annealing, steps for insertion of dfg, cavity preparation and restoration of direct filling gold
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Indian Dental Academy: will be one of the most relevant and exciting training center with best faculty and flexible training programs for dental professionals who wish to advance in their dental practice,Offers certified courses in Dental implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic Dentistry, Periodontics and General Dentistry.
DENTAL CASTING ALLOYS
Mostly metals used in dentistry are in the form of alloys or mixture of one or more metals.
Alloy: two or more metal that are mutually soluble in each other in the molten state.
Metal: Any strong and relatively ductile substance that provide electropositive ions to a corrosive environment and that can be polished to a high luster.
Uses of metal or alloys in dentistry:
For direct intra-coronal restoration such as using direct filling gold.
Fabrication of extra-coronal restoration such as inlays, onlays, crown and fixed partial denture.
For fabricating superstructure, cast frameworks, cast partial denture etc.
For surgical use such as making titanium plates, screws etc.
For orthodontic use in making wires, brackets, bands etc.
For making laboratory instruments etc.
Properties of metal:
Should have high strength.
Should be malleable and ductile.
Should have good thermal and electrical conductivity.
Should have high luster.
Should have high corrosion resistance .
Structure of metal:
All metals are crystalline in nature.it refers to regular arrangement of atoms. There are six different type of crystal structure:
a) Cubic
- Simple
- Body-centered
- Face conferred
b) Tetragonal
- Simple
- Body-centered
- Rhombohedric
c) Orthorhombic
- Simple
- Body-centered
- Face-centered
- Base centered
d) Monoclinic
- Simple
- Base centered
e) Triclinic
f) Hexagonal
Crystal lattice structure
Classification of dental casting alloys
On the basis of use
alloys for all metal and resin veneer restorations
alloys for metal ceramic restoration
alloys for post and core
alloys for removable partial denture
alloys for dental implants
on the basis of major elements
gold based alloys
palladium based
silver based
nickel based
cobalt based
titanium based
on the basis of three major elements
gold-palladium-silver
palladium-silver-tin
nickel-chromium-molybdenum
cobalt-chromium-molybdenum
iron-nickel-chromium
titanium-aluminum-vanadium
on the basis of nobility
o high noble metal alloy
o noble metal alloy
o Predominantly base metal alloy
o Base metal alloy
On the basis of dominant phase system
Single phase or solid solution alloys
Eutectic alloys
Peritectic alloys
Intermetallic compound
Alloys for all metal restoration
Earlier days metal restoration was choice for replacement of missing teeth, but as an advancement of new material and because of color of metal, the uses of metallic restoration have reduced. However, the metal alloys continue to be used in metal-ceramic restoration to enhance strength, wear resistance and hardness.
Classification:
Based on their yield strength, percentage elongation and use, alloys for all metal restorations are classified into
Type I soft
Small inlays, class III and class IV cavities which are not subjected to wear great stress.
Type II medium
For inlay, onlays and partial veneer crown, abutm
Base-Metal-Alloys used in dentistry..pptxKalpanaNunia1
Dentists should be aware of the corrosion properties and biocompatibility of any alloy they use.
In the absence of detailed data on corrosion for an alloy, use of high-noble and noble alloys of single-phase microstructure will minimize biologic risk.
Patients with Ni allergy may have sensitivity for cobalt. Such patients should be tested to rule out allergy before giving Co-Cr restoration.
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Indian Dental Academy: will be one of the most relevant and exciting training center with best faculty and flexible training programs for dental professionals who wish to advance in their dental practice,Offers certified courses in Dental implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic Dentistry, Periodontics and General Dentistry.
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Indian Dental Academy: will be one of the most relevant and exciting training center with best faculty and flexible training programs for dental professionals who wish to advance in their dental practice,Offers certified courses in Dental implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic Dentistry, Periodontics and General Dentistry.
Indian Dental Academy: will be one of the most relevant and exciting training center with best faculty and flexible training programs for dental professionals who wish to advance in their dental practice,Offers certified courses in Dental implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic Dentistry, Periodontics and General Dentistry.
PRESENTATION ON GOLD ALLOYS USED IN DENTISTRY. USEFUL FORALLBRANCHES OF DENTISTRY SPECIALLY PROSTHODONTICS AND CONSERVATIVE DENTISTRY. INCLUDES VARIOUS CATEGORIES OF ALLOYS AND THEIR ADVANTAGES, DISADVANTAGES, USES ETC.
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3. Since antiquity, pure gold has been a
metal of special intrinsic and practical
value. From the dawn of civilization until
the present time, man has utilized gold in
some form or other in the practice of
dentistry.
4. In its pure form, gold has the unusual
ability to cohere to it self at room
temperature. Gold is quite soft, and in a
compressible form, increments can be
welded by pressure into a solid metal
mass.
5. Another unique feature about gold is it
inertness. Under most conditions it does
not tarnish, corrode or stain.
6. Its chief disadvantages are its color, high
thermal conductivity(53.20), and technical
difficulties in forming a dense restoration.
It has one of the highest densities of all
elements (19.3 g/cm3)
14. Gold Foil ( Robert
Woffendale 1795)
Oldest of all products standard No. 4 Gold foil
4 x 4 inch sheets weight 4 grains (0.259g) and
0.51µm thick
No. 3 weight 3 grains – 3 µm thick.
15. Cohesive - Noncohesive
Gold:
Gold attracts gases and any adsorbed gas
film prevents intimate atomic contact
required for cold welding
- Manufactures supply free of surface
16. NON COHESIVE FOIL:
Majority are provided with an adsorbed
protective gas film like ammonia
-
Prevents premature cohesion of sheets
that may come into contact. Volatile film
is removed by heating to restore the
cohesive character of the foil.
17. Gold Foil Cylinders:
Formed by rolling cut segments of
No. 4 foils into a desired width
- 3.2mm, 4.8mm, 6.4mm using modified
No.22 tapestry needle.
18. Preformed Gold Foils:
Cylinders and ropes are now
available in preformed shapes made
from No.4 foil which has been
‘carbonised’ or corrugated
• Historical interest Great Chicago fire of
1871
19. Platinised Gold Foil:
It is a laminated structure can be
produced in
one of the 2 ways.
4. 2 sheets of No.4 pure gold foil and a
layer of pure platinum foil sandwiched
between there can be hammered until
the thickness of No.4 sheet is obtained.
20. 2. Layers of platinum and gold can
be bonded together by cladding
process during the rolling
operation.
Objective of adding platinum:
Increases hardness and wear
resistance
21. Electrolytic Precipitate:
Crystalline gold powder formed by
electrolytic precipitation.
Powder is formed by sintering at an
elevated temp. well below the melting point of
gold, it causes self diffusion between
particles where they are in contact.
22. Mat Gold ( Rule 1937)
Is a crystalline, electrolytically
precipitated gold form that is formed
into strips .Preferred ease in building
up the internal bulk, more easily
compacted within and adapted to the
retentive portion of the prepared
cavity.
23. Disadvantages:
Because it is loosely packed it is
friable and contain numerous void
spaces.
2- material technique mat is
covered with a veneer of foil.
24. Mat foil
Sandwich of electrolytic precipitated
gold powder between sheets of No.3
gold foil
Purpose – Try to eliminate the need
to veneer the restoration with a layer of
foil
No longer Marketed
25. Alloyed electrolytic
precipitate
The newest forms of electrolytic
precipitate electro alloy RV is alloyed
with calcium. Calcium content of the
finished product is about 1%
Purpose is to produce stronger
restoration by dispersion strengthening
26. Powdered Gold:
1st used in early 1960’s
Gold powder was enclosed in No. 3
gold foil .maximum particle size is 74
µm Avg 15 µm
27. The atomized and chemically
precipitated powders are
1st mixed with a soft wax to form pellets
These wax – gold pellets wrapped with
foil
28. Removal of Surface
Impurities:
With the exception of non cohesive
gold the DFGs are received by the
dentist in a cohesive condition.
During storage and packaging they are
exposed to the atmosphere
29. It is necessary to heat the foil or pellet
before it is carried into the prepared
cavity. It is called
Annealing, heat treatment, degassing a
more appropriate term is desorption. It
is essential to achieve a cohesive mass.
30. Chamois finger tips should be worn by the
dentist to protect the gold from
contamination.
31. Proper desorption is a matter of heating
long enough at a temperature that removes
gases and in case of powdered gold burns
away the wax.
Temperatures in the range of 600-13000F
must be produced
Under heating should be avoided because it
does not adequately remove the impurities
32. Overheating should be avoided because
excessive sintering causes the material to
become more stiffer less ductile and
difficult to condense.
- Too Long time
- Too high temperature
Temperatures below 3150C are inadequate
33. The Gold can be heated in
two ways
1.Flame Heating
Flame annealing, held The alcohol flame
near the top of the is transparent; the
flame, flame from the
pellets is visible
35. When heating in bulk on a tray, excessive
amounts should be avoided, since the
difficulties arising from prolonged
heating can arise, from repeated heating
as well.
36. Handle the pieces with stain less steel wire
points that will not contaminate the gold.
Flame desorption occurs when the gold
segment has exhibited a dull red glow.
37. The fuel may be alcohol or gas but
alcohol is preferred because there is less
danger of contamination.
Alcohol must be pure methanol or
ethanol without colorants or additives.
38. Advantages of flame desorption
3. Ability to select a piece of
appropriate size.
4. Desorption of only these pieces used.
5. Less exposure to contamination.
6. Less danger of over sintering
39. DISADVANTAGES OF ELECTRIC ANNEALING
- Pellets may stick together, if the tray is
moved.
- Air currents may effect the uniformity of
heating
- Difficult to anneal appropriate amounts of
gold.
40. - Oversintering.
- Greater exposure to contamination.
- Size selection among the pieces of
desorbed gold is limited.
41. COMPACTION OF DIRECT FILLING
GOLD
Condensation is the procedure used to
condense and harden gold inside the cavity
preparation
2 main process
6. Welding
7. Wedging
43. Wedging refers to the pressurized
adaptation of the gold form within the
space between the tooth structure walls
that have been slightly deformed
elastically.
44. Straight points are cut in the prepared
cavity and the 1st pieces of foil are
wedged into these areas
45. COMPACTION:
Can be done by:
3. Hand mallet.
4. Pneumatic vibratory condensers.
5. Electrically driven condensers.
46. a. Nichrome wire used for carrying gold;
b. Pneumatic condenser
c. Detachable condensing tins
47. PHYSICAL PROPERTIES OF COMPACTED GOLD
1. Strength and Hardness:
BHN of pure gold is 25. During
condensation its hardness rises to 75.
Tensile strength rises from 19000 psi to
32000 psi.
Yield strength rises from 0 to 30,000 psi
48. 3) Density:
Density of pure gold is 19.3. Density of
well compacted direct gold is 16.5 cm3
The difference is due to the presence of
porosity and voids
4. Melting point of Gold-1063O C
49. 5.Tarnish and Corrosion Resistance:
Is good, there is very little marginal
leakage between the filling and cavity
walls, if the compaction is good.
6. It dissolves in aqua regia
7. high thermal conductivity (.710cal /sec
50. 6 Biocompatibility:
It is biocompatible. Produces
only a minimal pulpal response, if
compacted properly. The technique,
however, does involve a certain amount of
trauma to the tooth and its supporting
tissues.