Procedure For Amalgam Restoration

Procedure For Amalgam Restoration

Write a short note on trituration.
Answer:

Trituration is done to wet all the surfaces of alloy particles with mercury.

Objectives of Trituration:

• To remove the oxide layer.
• For pulverizing pellets into particles that can be easily wetted by mercury.
• To decrease the particle size as it increases the surface area of each alloy particle which leads to fast and complete amalgamation.
• To keep γ₁ and γ₂ matrix crystals as minimum as possible and to evenly distribute them throughout the mix for consistent amalgamation achieving adequate strength.
• To provide good amalgamation and to achieve a workable mix of amalgam in a short time this increases the working time for insertion, condensation, and carving of restoration.

Trituration is done by:

• Manual mixing
• Mechanical mixing.

Manual Mixing: In this glass mortar and pestle is used. Mortar has an inner surface that is roughened for increasing friction between amalgam and glass surface. Pestle is a glass rod with a round end.

During manual mixing operator should take the following precautions:

• Mortar should be rested on a firm base.
• Uniform pressure should be applied. A trituration pressure of 2 to 3 psi is needed for proper mixing.
• Time should be well controlled.
• The surface texture of the mortar and pestle is rough.

Dental Amalgam Separator

Mechanical Mixing:

• They are more commonly used to triturate amalgam alloys with mercury.
• Disposable capsules serve as mortar. Some capsules have cylindrical metal or plastic pieces in the capsule which serve as pestle. A capsule is inserted between the arms on top of the machines.
• When switched on the arms holding the capsule oscillate at high speed triturating the amalgam. Most amalgamators have hood that covers the arms holding the capsule in order to confine mercury spray and prevent accidents.
• Amalgamators have an automatic timer and speed control device. Its speed ranges from 3,200 to 4,400 cycles per minute.
• High-copper alloys require higher mixing speeds

Advantages of Mechanical Trituration:

• A uniform and reproducible mix is attained.
• The time required for trituration becomes much less.
• Contamination of the atmosphere by mercury is reduced.
• Alloy: Mercury ratio is good as it is proportioned by the manufacturer.