Page 132 - My FlipBook

128 OPERATIVE DENTISTRY

against thin walls. Again in cases where the condensing force should
be applied at an angle to the long axis of the shaft of the plugger
point as sometimes met with in distal cavities in posterior teeth with
a distal inclination. Hand pressure alone is required when it be-
comes necessary to use force at an angle which would tend to unseat
the filling.
A filling should never receive a blow through the plugging instru-
ment when that instrument does not point quite directly toward
one of the inner walls of the cavity, preferably the seat.
Mallet Force Alone is of service in adding the last poi'tions of
gold to an occlusal surface when adding thin layers of gold at each
time, resulting in a very hard surface.
A Good Rule is to increase the hand pressure (load) both in fre-
quency and weight as you increase the thickness of the pellets ap-
plied, and as the angle at which the gold is driven to a dentinal wall
approaches a right angle.
The Different Plans of Mallet Fores.
Hand Mallet. By far the best mallet force is the hand mallet
driven by an experienced assistant. By this method the operator is
able to vary the amount of hand pressure (load) and its relation to
the mallet force (velocity) at will all through the filling, as well as
at different points in the condensing of a single pellet of gold, a point
of no small consequence.
The Automatic Mallet. It has been attempted to imitate this
combination method in the automatic plugger, and is today the best
substitute for the hand pressure and assistant mallet method, but
it must be regarded as a substitute only and supplies a need in the
absence of better facilities.
Power Mallet. PoMer mallets either electric or mechanically
driven by the engine are of service in that part of each filling where
mallet force alone is indicated as previously described. But this
is such a small proportion of each filling that most operators do not
care to bother Avith them and few have them at hand.