Figure 1-2. Mechanical amalgamator.
c. Filling Amalgam Carrier. Modern dental amalgams use precise
proportioning methods for dispensing the mercury with the alloy. Since the mercury
content in the original mix is less than the maximum level of 55 percent, it is not
necessary to eliminate mercury from the amalgam before it is carried to the cavity
preparation. The amalgam is taken from the capsule and placed in an amalgam cup.
The amalgam carrier is loaded by forcing the open cylinder of the amalgam carrier into
the balled amalgam. The amalgam is then carried to the mouth and deposited in the
d. Condensation and Carving of Amalgam. Condensation is the process of
packing an amalgam mix into a cavity preparation. Both time and pressure are
important to achieve the best results. Condensation must be accomplished before
crystals start to form. Delay will result in a breakdown of these crystals and a weakened
amalgam. Sufficient condensation pressure is necessary to prevent voids in the
restoration. The amount of pressure varies with each type of amalgam. Usually the
amalgam restoration is well set and hardened so that carving can be started with sharp
instruments immediately after condensation. The carving operation results in a
completely restored tooth.
PRECAUTIONS DURING AMALGAM PREPARATION
Four possible adverse effects.
(a) Excessive expansion of the amalgam.
(b) Postoperative pain.