For a class V gold restoration, the mesial and distal cavity margins should end at the line angles of the tooth to ensure proper adaptation and prevent overhangs. This is important for both functional and aesthetic reasons

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.

Natural glaze is often more durable and permanent compared to applied artificial glaze, providing a better finish.

Dental amalgam has been a traditional restorative material for many years, known for its durability and strength. However, there is a growing trend towards the use of more aesthetic materials, such as composites and glass ionomers, which blend better with natural tooth structure.

Explanation: In a conventional Class III amalgam cavity preparation, the axial wall should be straight and parallel to the long axis of the tooth. This design ensures that the restoration has adequate resistance form and is less likely to dislodge under occlusal forces. The wall being deeper incisally than gingivally helps to maintain the integrity of the tooth structure and provides a stable base for the amalgam restoration.