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1 Conservative Dentistry

Annealing of gold foil is the process by which�
�1. Contaminants are removed from the surface
�2. Rigidity decreases and ductility increases
�3. Both ductility and propotional limit decrease
�4. None of the above

Option 1

Annealing gold foil is the process of heating gold to remove impurities and restore its cohesion properties.�

Annealing of gold foil is a heat treatment process used to alter the physical and sometimes chemical properties of the material. The primary purpose of annealing gold foil is to remove any contaminants and stresses that may be present on the surface of the material. This is achieved by heating the gold foil to a specific temperature, typically around 400�C (750�F), and then allowing it to cool slowly. The process can also help in improving the foil's ductility, making it more malleable and easier to work with. However, the direct effect of annealing on the rigidity, ductility, and proportional limit is not explicitly stated in the question, and thus the correct answer is that annealing of gold foil primarily serves to remove contaminants from the surface.

Option 2

Option 3

Option 4

2 Conservative Dentistry

The final polish of a cat gold alloy to achieve a smooth polished surface is done by
1) Pickling
2) Electropolishing
3) Sandblasting
4) Rouge

Option 1

Option 2

Option 3

Option 4

The final polish of a cast gold alloy to achieve a smooth polished surface is done by

1) Pickling: This is a process used to remove oxides and impurities from the surface of a metal before applying a final finish. However, it does not provide the final polish.
2) Electropolishing: This technique uses an electrical current to dissolve the metal surface and create a smooth finish, but it is not commonly used for gold alloy restorations.
3) Sandblasting: This method involves propelling an abrasive material against the metal surface to smooth and clean it, but it is too aggressive for the final polish of a gold alloy restoration.
4) Rouge: Rouge is a fine abrasive paste used with a polishing wheel or point to achieve the final polish on a cast gold alloy restoration. It removes minor imperfections and gives a high luster to the metal.

The correct answer is 4) Rouge, as it is the standard technique for achieving a smooth, polished surface on cast gold alloys.

3 Conservative Dentistry

The polishing agent which can be used to polish amalgam restoration is
1) Garnet
2) Emery
3) Silex
4) Alumina

Option 1

Option 2

Emery is a polishing agent that can be used to polish amalgam restorations. It is a natural abrasive material that is relatively safe for metal surfaces and does not cause significant wear on the amalgam. Garnet, silex, and alumina are also abrasive materials, but they are less commonly used for polishing amalgam due to potential issues with scratching or wearing down the restoration.

Option 3

Option 4

4 Conservative Dentistry

Aluminium oxide polishing powder is obtained from
1) Aluminium
2) Cryolite
3) Bauxite
4) Vulcanite

Option 1

Option 2

Option 3

�Aluminium oxide (Al₂O₃) is primarily derived from bauxite, which is an ore that contains a high percentage of aluminium. The Bayer process is commonly used to extract aluminium oxide from bauxite.

Option 4

5 Conservative Dentistry

When dental bur is sterlized by autoclaving, which of the following chemicals is used for protection of the bur
1) Sodium nitrate
2) Sodium nitrite
3) Silver nitrate
4) Silver nitrite

Option 1

Option 2

Explanation:

Sodium nitrite is often used as a protective agent during the autoclaving process to prevent corrosion of dental instruments, including burs. It helps to maintain the integrity of the metal during the sterilization process.

Option 3

Option 4

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