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.

DENTAL INSTRUMENTS

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 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

hand instruments

Definition: Hand instruments are those instruments that are used manually without a power source

HAND INSTRUMENTS ARE COMPOSED OF THREE PARTS:

1\Handle.2\Shank. 3\working end (Blade Or nib).

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

DIAGNOSTIC INSTRUMENTS

PLASTIC INSTRUMENTS

1\DYCAL

APPLICATOR

2\SPATULA

AMALGAM INSTRUMENTS

1\AMALGAM CARRIER

2\CONDENCERS

3\CARVERS

4\BURNISHERS

CUTTING INSTRUMENTS

EXCAVATOR

1)ORDINARY HATCHET2) HOE3) ANGLE FORMER4) SPOON

CHISELS OTHERS

1) CHISEL2)ENAMEL HATCHET3) GINGIVAL MARGIN TRIMMER

1)KNIVES2)FILES3)SCALERS4)CARVERS

EXCAVATORS

CHISELS

OTHER CUTTING INSTRUMENTS

1\FILES 2\KNIFES

3\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

Thank you