Gold is a soft, yellow metal with an atomic number of 79. It is very malleable and ductile, and can be drawn into extremely thin wires. Gold is the oldest dental restorative material, dating back over 4000 years, when it was used for dental repairs and bridges. Modern dental uses of gold include fillings, crowns, bridges, and veneers. However, pure gold does not have high mechanical resistance, so it is only suitable for small cavities. Alloys are typically used instead, combining gold with other metals in varying amounts depending on the karat rating. Biocompatibility is important for dental materials to prevent corrosion between dissimilar alloys. New electroforming techniques using pure gold

2. Intro
• Gold, (symbol Au) has an atomic number
of 79 i.e. each gold atom has 79 protons
in its nucleus.

3. • The metal gold is extremely malleable.
(sheet form)
• Gold is also ductile and one ounce can
be drawn into 80 km (50 miles) of thin gold
wire (5 microns diameter)

4. • Gold has a Young's modulus of 79 GPa
which is very similar to silver

5. Purity of gold
24 kt gold is pure gold.
18 kt gold contains 18 parts gold and 6 parts of
another metal(s), making it 75% gold.
14 kt gold contains 14 parts gold and 10 parts of
another metal(s), making it 58.3% gold.
12 kt gold contains 12 parts gold and 12 parts of
another metal(s), making it 50% gold.
10 kt gold contains 10 parts gold and 14 parts
another metal(s), making it 41.7% gold. 10K
gold is the minimum karat

6. •Gold is the oldest dental restorative
material, having been used for dental
repairs for more than 4000 years.
•The early dental applications were based
on esthetics, rather than masticatory ability

7. •The early Phoenicians used gold wire to
•bind teeth, and subsequently, the Etruscans and
then the Romans introduced the art of making
fixed bridges from gold strip.
•During the Middle Ages these techniques were
lost, and only rediscovered in a modified form in
the middle of the nineteenth century.

8. Gold Alloys

9. Gold Types Used in Dentistry

10. Detailed values of Gold Alloys in
Dentistry

12. Since gold fillings do not have high mechanical
resistance against masticatory forces, they are
only suitable for very small cavities.
In recent years pure gold has also been used
through the electroforming process.
Electroformed inlays and onlays are suitable to
be cemented into cavities after they have been
veneered with porcelain.

13. Tooth restorations such as porcelain
veneered copings for crowns and
bridgework can be electroformed with pure
gold.
Unfortunately, no standard yet
exists for this process, which is rapidly
becoming an established mainstream
technique in modern dentistry.

14. Biocompatibility of gold
Besides functional performance and aesthetics,
biocompatibility is a third important requirement for
dental restorative materials.
Where dental restorations are based on the use
of different alloys, there is the obvious potential for
oral poly-metallism.
Two alloys of different composition have different
electrochemical potentials, and
inevitably induce corrosion and “Galvanism”

15. • This phenomena may lead to the deterioration of dental
devices may cause prosthesis failure or fracture.

16. The Future of Gold in
Dentistry
The development of electroforming
technology with pure gold offers new
opportunities for future research.

17. It is also considered that as CAD/CAM
technology progresses, special high gold
alloys should be developed, which are well
suited to milling and grinding operations and
have sufficiently high strength for long span
bridges and small cross sections

19. Thank
you