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dental casting investments: overview

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Investment, also known as dental casting investment or investment powder, is a crucial material used in the process of creating dental restorations through the lost-wax casting technique. This technique involves creating a mold of the dental restoration in wax, then surrounding it with investment material. Once the investment sets and the wax is burned out, molten metal is poured into the mold to create the final dental restoration. Here's an overview of investment used in dental casting: **Composition:** Dental casting investment is composed of several components that contribute to its properties and performance during the casting process. The main components include: 1. **Refractory Material:** The primary ingredient is a refractory material, often silica or a mixture of silica and other materials. This material can withstand high temperatures without melting or deforming. 2. **Binder:** A binder is added to hold the refractory particles together, providing strength t

Physical properties of dental materials

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 Dental materials possess various physical properties that are crucial for their clinical performance. These properties include: 1. ** Density **: The mass of a material per unit volume. 2. ** Hardness **: The resistance of a material to indentation or scratching. 3. ** Elasticity **: The ability of a material to return to its original shape after deformation. 4. ** Flexibility **: How easily a material can be bent or flexed without breaking. 5. ** Compressive Strength** : The maximum compressive load a material can withstand without breaking. 6. ** Tensile Strength* *: The maximum tensile load a material can withstand without breaking. 7. ** Fracture Toughness **: The ability of a material to resist crack propagation. 8. ** Coefficient of Thermal Expansion **: The change in volume or length of a material with a change in temperature. 9. ** Thermal Conductivity* *: The ability of a material to conduct heat. 10. ** Electrical Conductivity **: The ability of a material to co

Dental amalgam

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Dental amalgam is a filling material used in dental restorations. It consists of: • Mercury - The main component is liquid elemental mercury, usually around 44-54% by weight. • Metal alloys - The main metals used are silver, tin, and copper, which are mixed in powdered alloy form.  • Other components - Sometimes zinc or palladium are added in small amounts. When dental amalgam is mixed, the liquid mercury binds to the metal powder through an amalgamation reaction, forming an alloy with a property called "gamma 1 intermetallic compound". This compound is malleable and can be shaped as a dental filling.  Once placed in the tooth, the amalgam further hardens due to loss of mercury and corrosion within the mouth. This makes it fairly durable for restoring damaged teeth. However, there are some concerns about dental amalgam: • Mercury exposure - There is debate about whether low levels of mercury vapors from dental amalgam can cause health issues over time, especially