Clean the exterior of the unit and inspect the electrical
cord and plug before each use.
The heating element is housed inside a metal
assembly at the very top portion of the unit. This
section will become extremely hot when in use. Use
caution. Before use, inspect the vacuum holes in the
platform to make sure they are not obstructed. Inspect
the rubber sealing gasket for cracks and deterioration.
The vibrator (fig. 8-21) is used to move dental
plaster or dental stone mixes when pouring a cast. The
vibrator also increases the density of the mix by
eliminating air bubbles. A rheostat control is used to
adjust the intensity of the vibration from a gentle
agitation to a vigorous shaking.
To maintain the vibrator, cover the rubber
platform and body of the unit with a plastic cover. As a
safety precaution, check the power cord and plug for
defects before use.
Some of the common prosthodontic instruments
you and the dentist will use during patient treatment
and in the fabrication of dental prostheses are
explained in the following paragraphs.
To remove a crown from a tooth, the dentist uses a
crown remover instrument (fig. 8-22). The handle on
the crown remover is encircled with a heavy-steel
weight that slides from one end of the handle to the
other. Two interchangeable points make up the
working end. One of these points is contra-angled and
the other is straight. Both points have a right-angle
Figure 8-21 .-Vibrator.
Figure 8-22.Crown remover.
projection at the top. When the crown remover is used
properly, the tip is placed over the margin or junction
of the crown and tooth first. Then the sliding weight on
the handle is tapped against the bottom part of the
The roach carver (fig. 8-23) is a double-ended
instrument used to cut, smooth, and carve dental
waxes. At first glance, it appears to look like a wax
spatula. A closer look reveals a spear-shaped blade at
one end, with a deep-welled, very small spoon at the
other end. Both ends have very sharp edges. The
deep-welled end may al so be used to carry melted wax.
Usually, two kinds of knives are used in the
prosthodontic treatment room: the compound knife
and plaster knife. As the names imply, one is used with
compound, and the other with plaster.
The compound knife (fig. 8-24) has a fairly large,
red plastic handle and detachable blade. Routinely the
#25 blade is used to trim impression compound, wax,
and other materials that require an extremely sharp
cutting edge. The blade is almost identical to a larger
version of the #11 surgical blade. Your primary
concern with the compound knife is to replace broken
or dull blades.
Figure 8-23.Roach carver.