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OPERATIVE DENTISTRY 07

PART I

CHAPTER I. o ^
INSTRUMENT NOMENCLATURE. i^
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A dental instrument is an appliance, or tool, by means of which
a dentist performs dental operations. It is quite essential that we
learn the names and uses of the instruments most in use if we are
to understand the teachng of operative procedures.
Instruments are named according to the purpose for which they
are intended, where and how used, by describing their working
points and the shape of their shank.
An order name describes that for Avhich an instrument is used,
as for example, excavator, clamps, mallet, pluggers, burnishers, etc.
A sub-order name describes where or how an instrument of a
given order is used and is made by inserting a prefix before the or-
der name. Examples are hand pluggers, push or pull scalers, etc.
A class name describes the Avorking point of an instrument. Ex-
amples are serrated plugger, ball burnisher, chisel, hatchet, etc.
A sub-class name describes the shape of the shank, and is made
by prefixing this description to the class or order name or to both
combined. Examples are bayonet plugger, bin-angle chisel, mon-
angle hatchet excavator, etc.
Rights and lefts are made as further divisions of manj^ of the
sub-classes of instruments and this division is especially advan-
tageous in the spoons, bin-angle, contra-angle hatchets and mar-
ginal trimmers, as it enables the user to do the work by a move-
ment of the instrument from right to left, or left to right, respec-
tively.
An excavator is that order of hand instrument used in the re-
moval of tooth substance preparatory to the making of a filling.
A chisel is that class of excavator which has the cutting edge
placed at right angles to the shaft, is sharpened by grinding on
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