DR.LINDA MEHAR. INSTRUMENTS: The term instrument refers to a tool or device used for specific purpose or procedure. The dental operator must have complete.
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INSTRUMENTS: The term instrument refers to a tool or
device used for specific purpose or procedure.
The dental operator must have complete knowledge of the purpose and applications of instruments required to perform dental procedures
1\instruments available 2\the purpose of instrument 3\the position and manner of use
MATERIALS USED
CARBON STEEL
Advantages: Harder than stainless
steel. It loses sharpness
slower than stainless steel.
Disadvantage: More corrosion
(rusting) tendency during sterilization.
STAINLESS STEEL
Advantages: Less corrosion
(rusting) tendency during sterilization.
Disadvantages:Less hard
comparatively. It loses sharpness
quicker during much use.
SOME INSTRUMENTS ARE MADE OF CARBIDE TO PROVIDE MORE DURABLE CUTTING EDGE.
OTHER ALLOYS: alloys of nickel , cobalt or
chromium are used
CLASSIFICATION
1\HAND INSTRUMENTS A\CUTTING INSTRUMENTS B\NON CUTTING INSTRUMENTS2\ROTARRY INSTRUMENS MAINLY CUTTING
INSTRUMENTS
1\HANDLE It is the part of the instrument grasped
by the operators hand Handles are in conjunction with the
shank or it may be separated Separate type handles allows for
replacement of several working ends e.g. mirrors and condensers
2\SHANK The part that Connect the handle to the
working end Usually smooth, round and tapered Have one or more angles
3\Working end It is the working part of the instruments Begins at the point which terminate the
shank On cutting instruments it is called
(blade) On non cutting instruments it is
called(nib)
CLASSIFICATION OF HAND INSTRUMENTS
One of the earliest classification of instruments was proposed by G.V. Black
G.V. Black classified all instruments based on the use of the instruments to:
Non-cutting instruments. Cutting instruments.
NON CUTTING INSTRUMENTS
Diagnostic instruments
1) MIRROR2) PROBE3) TWEEZER
Plastic instruments
1) DYCAL APPLICATOR2) CEMENT SPATULA
Amalgam instrument
s
1) AMALGAM CARRIER2) CONDENSER3) BURNISHER4) CARVER
CUTTING INSTRUMENTS
EXCAVATOR
1)ORDINARY HATCHET2) HOE3) ANGLE FORMER4) SPOON
CHISELS OTHERS
1) CHISEL2)ENAMEL HATCHET3) GINGIVAL MARGIN TRIMMER
1)KNIVES2)FILES3)SCALERS4)CARVERS
NOMENCLATURE Black classified all instruments by name
according to 1\function (e.g. scalar ,excavator) 2\manner of use (e.g. hand scalar) 3\design of the working end (e.g. spoon
excavator) 4\shape of the shank (e.g. mono angle –bi
angle-contra angle) These names were combined to form the
complete description of the instrument (e.g. bi angled spoon excavator)
INSTRUMENTS FORMULA
HAND CUTTING INSTRUMENTS HAVE FORMULA’S DESCRIBING THE DIMENTIONS AND ANGLES OF THE WORKING END
These are placed on the handle using a code of three or four numbers separated by dashes(e.g. 10-85-8-14)
This formula consists of three units:1\ Blade width: expressed in tenth of
millimeters.2\Blade length: expressed in
millimeters.3\ Blade angle: expressed in
centigrade ,this represents the angle of the blade relative to the long axis of the handle of the instrument.
For instruments in which the primary cutting edge is at a right angle (90) to the long axis of the blade the formula composed of three digits
10-14-16
if the primary cutting edge is other than 90 degree to the long axis of the blade then the Primary cutting edge angle(in centigrade) is added to the formula(four digits formula) This number is placed in the second position of the formula
1-blade width 2-primary cutting edge angle 3-blade length 4-blade angle
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