slide1 n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
HAND INSTRUMENT PowerPoint Presentation
Download Presentation
HAND INSTRUMENT

Loading in 2 Seconds...

play fullscreen
1 / 111

HAND INSTRUMENT - PowerPoint PPT Presentation


  • 207 Views
  • Uploaded on

HAND INSTRUMENT. Contantes. • Sharpening Stationary sharpening Mechanical sharpening. • Introduction Definition History. • Classification Cutting instrument Non cutting. • Instrument grasp Modified pen. Inverted pen. Palm and thumb.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'HAND INSTRUMENT' - oshin


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide3

Contantes

•Sharpening

Stationary sharpening

Mechanical sharpening

•Introduction

Definition

History

•Classification

Cutting instrument

Non cutting

•Instrument grasp

Modified pen.Inverted pen.

Palm and thumb.

Modified palm and thumb.

•Cutting instrument

MATERIALS

Hardening and Tempering

Heat Treatments

Design

Shank angles

Nomenclature

Formula

Bevels

•Cleaning and Sterilization

•Non cutting instrument

Amalgam condenser

Mouth mirror

Others

•Cutting instrument applications

Excavators

Chisels

slide4

Introduction

Definition :

It is hand-powered dental instruments.

History :

The early hand-operated instruments characterized by:

Large, heavy handles and inferior metal alloys in the blades.

cumbersome, difficult to use, and ineffective in many situations.

slide5

there was no uniformity of manufacture or nomenclature, Many dentists made their own hand instruments inan effort to find a suitable instrument for a specific need.

effective sterilization was a problem.

Designs of some early hand instruments

slide6

G.V. Black is credited with the first acceptable nomenclature and classification of hand instruments.

His classification system enabled both dentists and manufacturers to communicate more clearly and effectively in regard to instrument design and function.

G.V. Black

slide8

Cutting Instrument

MATERIALS

Hand cutting instruments are manufactured from two main materials.

carbon steel

stainless steel

remains bright under most conditions.

Is harder than stainless steel.

loses a keen edge during use much more quickly than does carbon steel

when unprotected, it will

corrode.

slide9

MATERIALS

Tungsten carbide inserts or blades to provide

more durable cutting edges (brittle). They may

be soldered to steel handles.

some instruments are made with carbide to

provide more durable cutting edges.

slide10

MATERIALS

Other alloys of nickel, cobalt, or chromium are used in the manufacture of hand instruments.

Carbon steel

Stainless Steel

slide11

MATERIALS

Hardening and Tempering Heat Treatments:

To gain maximal benefits from carbon steel or stainless steel, the manufacturer must submit them to two heat treatments: hardening and tempering .

Heat treatment Furnace

slide12

MATERIALS

The hardening heat treatment hardens the alloy, but it also makes it brittle, especially when the carbon content is high.

Heat treatment relieves strains and increases toughness. the tempering

Heating or flaming of hand instruments

during dental use can alter the original

properties of the alloy and render it

unserviceable.

slide13

Design

Most hand instruments composed of three parts :

a- Blade or nib

b-Shank

c-Handle

slide14

Design

a- blade

This is the working part of the instrument.

Begins at the point which terminates the

shank.

It is connected to the handle by the shank.

Each blade has a cutting edge which is the

working part of the instrument.

It is usually in the form of a bevel (acute

angle) that cuts into the tooth structure.

On non cutting instruments e.g. condensers

the part corresponding to the blade is called the nib or face.

slide15

Design

b-shank

Connect the handle to the working end of the instrument.

Normally smooth, round and tapered.

Have one or more angles to avoid twisting of

the instrument.

Hand instruments must be balanced and sharp.

Balance allows for the concentration of

force onto the blade without causing

rotation of the instrument.

slide16

Design

Balance is accomplished by designing the

angle of the shank so that the cutting edge

of the blade must not be off axis by more

than 1-2 mm.

Shank angles:

Mon-angle, bin-angle, triple angle.

Instruments with small short blades may be

monangle

slide17

Design

Instruments with long blades may required

two or three angles in the shank to bring the

cutting edge near to the long axis of the

handle.

Such shanks are termed contra angled.

slide18

Design

c- handle(shaft)

It is the part grasped in the operator’s hand.

Perfectly straight, smooth or eight sided.

Serrated for better gripping and control of the

instrument.

Handles are in conjunction with the shank or

it may be separable.

Separate type is known as cone-socket

handle and allows for replacement of several

working ends e.g. mirrors and condensers.

slide19

Design

mirror

cone-socket handle (mirror)

slide20

nomenclature

Black classified all instruments by name according to:

1. Function e.g. scaler, excavator.

2. Manner of use e.g. hand condenser.

3. Design of the working end e.g. spoon

excavator, sickle scaler

4. Shape of the shank e.g. mono-angle, biangle, contra-angle.

•These names were combined to form the

complete description of the instrument e.g.

binangle spoon excavator.

slide21

formula

Hand cutting instruments have formulas

describing the dimensions and angle of

the working end.

These are placed on the handle using a

code of three or four numbers separated

by dashes or spaces (e.g. 10-85-8-14).

The first number indicates

the width of the blade in

tenths of a mm (e.g. 10 = 1 mm).

The second number primary cutting edge angle

measured from a line parallel to the long axis of

the handle in clockwise centigrade.

slide22

formula

Instrument shank and

blade design with formula.

slide23

formula

If the edge is perpendicular to the blade,

this number is omitted resulting in a 3

numbers code.

The third number indicates the blade

length in mm (e.g. 8 = 8 mm).

The fourth number indicates the blade angle relative to the

long axis of the handle in clockwise centigrade e.g. (14)

Additional number on the handle is the manufacturer’s identification number.

slide24

formula

Additional numbershould not be confused with the formula number.

slide25

Bevels

Most hand cutting instruments have on the end of the blade a single bevel that forms the primary cutting edge. Two additional edges,

Additional two secondary cutting edges that

extend from the primary cutting edge for the

length of the blade.

This allows cutting in 3 directions; facial and

lingual walls of the proximal cavity.

Chisel blade design showing primary and secondary cutting edges.

slide26

Bevels

Bibeveled instrument have

two bevels that form the

cutting edge,

e.g. hatched excavator.

slide27

Bevels

Single beveled

instrument such as

spoon excavator

and gingival

margin trimmer are

used with lateral

cutting movement.

slide28

Bevels

Enamel hatchet also as a single beveled instrument used with direct cutting motion, a

planning or lateral cutting

designated for right and left to

the instrument formula.

slide29

Bevels

Right and left bevels

To determine this, the primary cutting edge is held down and pointing away.

If the bevel appears on the right, it is in the right instrument of the pair, when used it is moved from right to left.

The opposite is true for the left instrument of the pair.

One instrument is used for work on one side of the preparation and the other for the opposite side of the preparation.

slide30

Bevels

The cutting edge is perpendicular to the axis of the handle

e.g. binangle chisel.

Instrument with slight blade curvature e.g.Wedelstaedt chisel.

slide31

Cutting instrument applications

Applications can be classified into:

-Removal of caries and refinement of the internal parts of the preparation.

-Used primarily for cutting enamel.

slide33

CUTTING INSTRUMENT APPLICATIONS

Hatchet excavator

It has the cutting edge of the blade directed in the same plane as that of the long axis of the handle and is bibeveled .

slide34

CUTTING INSTRUMENT APPLICATIONS

Hatchet excavator

These instruments are used primarily on anterior teeth for preparing retentive areas and sharpening internal line angles, particularly in preparations for direct gold restorations .

slide35

CUTTING INSTRUMENT APPLICATIONS

Hoe excavator

IT has the primary cutting edge of the blade perpendicular to the axis of the handle

slide36

CUTTING INSTRUMENT APPLICATIONS

Hoe excavator

This type of instrument is used for planing tooth preparation walls and forming line angles. It is commonly used in Classes III and V preparations for direct gold restorations.

slide37

CUTTING INSTRUMENT APPLICATIONS

Hoe excavator

Some sets of cutting instruments contain hoes with longer and heavier blades, with the shanks contra-angled. These are intended for use on enamel or posterior teeth.

slide38

CUTTING INSTRUMENT APPLICATIONS

Angle former excavator

It is mon-angled and has the primary cutting edge at an angle (other than 90 degrees) to the blade. It is available in pairs (right and left )

slide39

CUTTING INSTRUMENT APPLICATIONS

Angle former excavator

It is used primarily for sharpening line angles and creating retentive features in dentin in preparation for gold restorations.

It also may be used in placing a bevel on enamel margins

slide40

CUTTING INSTRUMENT APPLICATIONS

Spoon excavator

Its blades are slightly curved, the shanks may be bin-angled or triple-angled to facilitate accessibility.

-the cutting edges are claw like.

- the cutting edges are circular.

slide41

CUTTING INSTRUMENT APPLICATIONS

bin-angled spoon

triple-angled spoon

slide45

CUTTING INSTRUMENT APPLICATIONS

straight, slightly

curved, or bin-angle

The straight chisel has a straight shank and blade, withthe bevel on only one side. Its primary edge is perpendicular to the axis of the handle.

slide46

CUTTING INSTRUMENT APPLICATIONS

straight, slightly

curved, or bin-angle

The shank and blade of the chisel also may be slightly curved (Wedelstaedt design)

slide47

CUTTING INSTRUMENT APPLICATIONS

straight, slightly

curved, or bin-angle

The shank and blade of the chisel also may be bin-angled .

slide48

CUTTING INSTRUMENT APPLICATIONS

straight, slightly

curved, or bin-angle

The force used with all these chisels is essentially a straight thrust.

There is no need for a right and left type in a straight chisel, since a 180-degree turn of the instrument allows for its use on either side of the preparation.

slide49

CUTTING INSTRUMENT APPLICATIONS

straight, slightly

curved, or bin-angle

The bin-angle and Wedelstaedt chisels have

the primary cutting edges in a plane perpendicular tothe axis of the handle and may have either a distal bevel or a mesial (reverse) bevel.

slide50

CUTTING INSTRUMENT APPLICATIONS

straight, slightly

curved, or bin-angle

The blade with a distal bevel is designed to plane a wall that faces the blade's inside surface

slide51

CUTTING INSTRUMENT APPLICATIONS

The blade with a mesial bevel is designed to plane a wall that faces the blade's outside surface

slide52

CUTTING INSTRUMENT APPLICATIONS

enamel hatchet

It is a chisel similar in design to the ordinary hatchet excavator except that the blade is larger, heavier, and is beveled on only one side

It has its cutting edges in a plane that is parallel with the axis of the

handle.

slide53

CUTTING INSTRUMENT APPLICATIONS

enamel hatchet

It is used for cutting enamel and comes as right or left types for use on opposite sides of the preparation.

slide54

CUTTING INSTRUMENT APPLICATIONS

gingival margin trimmer

Similar in design to enamel hatchet except the blade is curved.

Right and left types:

Right pair is for either a mesial or distal

gingival margins.

Left pair is for a mesial or distal margins

slide55

CUTTING INSTRUMENT APPLICATIONS

gingival margin trimmer

slide56

CUTTING INSTRUMENT APPLICATIONS

gingival margin trimmer

When the second number in the formula is 90-100, it is used for distal gingival margins.

When this number is 75-85, the pair is used

to bevel the mesial margins.

100 and 75 pairs for steep margins for inlay

preparation while 90-85 for slight bevel in

amalgam preparations.

slide57

CUTTING INSTRUMENT APPLICATIONS

gingival margin trimmer

Uses of GMT :

Beveling of the gingival margins of proximoocclusal preparations.

Beveling of the axiopulpal line angle.

1

2

slide58

CUTTING INSTRUMENT APPLICATIONS

gingival margin trimmer

Performing a gingival lock (reverse bevel), placed on the gingival seat.

e.g. GMT 100 for the distal and GMT 75 for the mesial.

3

slide59

Sharpening

cutting instrument

sharpening

The cutting edge of the hand instrument should always be kept sharp as dull

instruments may cause:

1. Loss of control.

2. More pain.

3. Prolonged time for the operative procedure.

4. Reduce the quality and precision of tooth

preparation.

slide60

cutting instrument

sharpening

sharpening equipment

1

Stationary sharpening stone e.g. Arkansas stone, silicon carbide.

slide61

sharpening

2

Mechanical sharpener; moves at low

speed while the instrument is held at the

opposite angle and supported by a rest

i.e. easier and less time consuming.

Mechanical sharpener

slide62

Instrument grasp

There are four grasps used with the hand

instruments:

Modified pen.

Inverted pen.

Palm and thumb.

Modified palm and thumb.

With each grasp proper rest and guard is

important.

1

2

3

4

slide63

1. Modified pen grasp

It is similar to that used in holding a pen except

that the thumb, index and middle fingers contact

the instrument while the tips of the ring and little

fingers are placed on the working tooth as a rest..

The palm of the hand is facing away from the

operator.

slide64

pen grasp

Modified pen grasp

slide65

2. inverted pen grasp

If the hand is rotated so that the palm

faces more toward the operator.

If is used in the lingual and labial surfaces

of anterior teeth.

inverted pen grasp

slide66

3. Palm and thumb grasp (grasp of power)

The handle of the instrument is placed on the palm of the hand and grasped by all the

fingers while the thumb is free of the

instrument and rest on the nearby tooth of the same arch.

Palm and thumb grasp

slide67

4. Modified palm and thumb grasp

The same as in palm and thumb grasp but the thumb is rested on the tooth being prepared.

Used in the upper arch.

Modified palm and thumb grasp

slide68

Instrument rest

rests :

A proper instrument grasp must include a firm

rest (support) to steady the hand during

operative procedures.

The support may be gained from hard tissue.

Soft tissue rest or too distant hard tissue rest

does not afford a reliable control.

slide69

Indirect rest may be gained by using the

index finger of the opposite hand to rest

on the shank of the instrument.

The operating hand rests on the opposite

hand which rests on stable oral structures.

slide70

Instrument guards

guards :

The use of interproximal wedges to protect soft tissues from contact with sharp rotary cutting instruments.

slide71

Cleaning and Sterilization

Cleaning and Sterilization

Instrument Cleaning and Sterilization

slide72

Cleaning and Sterilization

Cleaning

All instruments need to be cleaned and thoroughly

dried before they are sterilized.

slide73

1-Hand Scrubbing

Advantages

-Effective if performed properly

Disadvantages

-Increases chances for operator injury.

-Increases spread of contamination through splatter.

-Labor-intensive.

-Need proper care of scrub brush

slide74

2-Ultrasonic Cleaning

Advantages

-Safer than hand scrubbing.

-Effectively cleans all instruments .

Reduces chances for spread of

contaminants through splatter.

-Allows for more efficient use of staff time

Disadvantages

-Microorganisms may accumulate in cleaning solution.

-Ultrasonic cleaning will not remove hardened Permanent cement. (Solution: remove cement while it is still soft.).

slide75

3-Automated Washer

Advantages

-Safer than hand scrubbing.

-Reduces chances for spread of contaminants of contaminants through splatter and aerosols.

-Allows for more efficient use of staff time.

-Effectively cleans instruments.

Disadvantages

-Not all instruments are compatible with automated washers.

-Please see manufacturer's instructions for detailed requirements.

slide76

Sterilization

  • process by which an article, surface or medium is freed of all living microorganisms.
    • -Most dental offices have a designated area for instrument reprocessing that is separate from the dental treatment room. This is ideal, since cleaning, sterilizing and storing instruments in the same room where the delivery of patient care is provided increases the risk of cross-contamination.
slide77

-Some instruments and materials

are single use only.

- Single-use items should be

segregated in the operatory,

and those that are sharp

or otherwise pose a risk of injury

must be discarded into a sharps container .

-Items without risk, such as

a saliva ejector, can be thrown into the trash.

-To prevent accidental injury with the contaminated instruments, special handling should be used to transport the instruments to the cleaning and sterilization area.

slide78

-Although heavy-duty gloves (utility gloves) may feel more awkward than examination gloves, they provide extra protection while handling instruments during the cleaning, rinsing, drying, packaging and sorting procedures that take place during instrument reprocessing

utility gloves

slide80

1-Steam preasure strillization

(autoclaving)

-Sterilization with steam under pressure is performed in a steam autoclave .

-For a light load of instruments, the time required at 250'F (121° C) is a minimum of 15 minutes at 15 lbs of pressure.

-Time for wrapped instruments can be reduced to 7 minutes if the temperature is

raised to approximately 273° F (134° C) to give30 pounds of pressure.

slide82

Advantages of Autoclaves.

-Autoclaving is the most rapid and effective method for

sterilizing cloth surgical packs and towel packs.

-Automated models are available.

-although they still can be misused or fail almost as often as nonautomated ones; they must be evaluated

with a biologic spore test monitoring system.

slide83

Disadvantages of autoclaves

-Items sensitive to the elevated temperature can not be autoclaved.

-Autoclaving tends to rust carbon steel instruments.

slide84

2-CHEMICAL VAPOR PRESSURE

STERILIZATION (CHEMICLAVING )

-Sterilization by chemical vapor under pressure is performed in a Chemiclave.

-Chemical vapor pressure sterilizers operate at 270° F (131° C) and 20 pounds of pressure.

-They are similar to steam sterilizers and have a cycle time of approximately half an hour.

slide85

Advantages of Chemiclaves.

-Carbon steel and other corrosion-sensitive burs, instruments, and pliers are said to be sterilized without rust or corrosion.

Disadvantages of Chemiclaves.

- Items sensitive to the elevated temperature will be damaged.

-Instruments must be lightly packaged in bags obtained from the sterilizer manufacturer.

- Towels and heavy cloth wrappings of surgical instruments may not be penetrated to provide sterilization.

- Routinely use biologic spore test monitoring strips to confirm heat penetration of heavy packs before use.

slide87

3. Dry heat sterilization (dryclave)

  • Is an excellent means of sterilization sharp instrument but rubber and plastic material can not be sterilized by this method .
  • -Dry heat sterilizers for use in dental offices are available, but all that is necessary is an oven that will maintain a temperature of 160°C(320°F)

-It imperative that all debris be removed from an instrument before it placed in a dry heat sterilizer .

*Holding period : 160°C(320°F),1 hour .

slide88

Advantages of this method

1-is an excellent means of sterilization sharp instrument.

2-instrument not corrode or rust.

Disadvantages

1-a lower temperature or a shorter period will not produce the desired result .

2-The higher temperature of a dry-heat sterilizer means that paper will scorch and plastic will melt.

3-some hand pieces can not be sterilized by this method

slide90

4-ETHYLENE OXIDE STERILIZATION

-Ethylene oxide sterilization is the best method for sterilizing complex instruments and delicate materials.

-ethylene oxide gas is toxic for all viruses and bacteria at room temperature on exposure for 8-10 hr at elevated temperature .

-this method requires rather expensive equipment .

slide92

BOILING WATER

*Boiling water does not kill spores and cannot sterilize

instruments. However, heat can reach and kill blood borne pathogens in places that liquid sterilants and disinfectants used at room temperature cannot reach.

*Boiling is a method of high-level disinfection that has been used when actual sterilization cannot be achieved (e.g., in case of a sterilizer breakdown)

slide93

New methods of sterlization

**Various new methods of sterilization are under investigation and development.

-The microwave oven has major limitations for sterilizing metal items, by either damaging the machine or not reaching all sides of the instruments.

microwave oven

slide94

-Ultraviolet light is not highly effective against RNA viruses such as HIV and is not very effective against bacterial spores

Ultraviolet light

slide95

-Incomplete exposures of all surfaces and poor penetration of oil and debris are other limitations.

- Ultraviolet irradiation may be useful for sanitizing room air to help control tuberculosis bacteria .

slide96

Instrument storage in dental cabinet

1-After the instrument are sterilized, they are placed in proper place in a dry condition .

2-The portions of dental cabinet designated for hand instrument contain grooved glass or metal trays.

3-These instrument containers must be kept in clean and aseptic condition.

4-hey should also contain protective medium for

cutting edges of the instrument .

slide98

Effects of Sterilization

Sterilizing carbon steel instruments by any of (cold disinfection, boiling water, steam under pressure (autoclave) causes discoloration, rust, and corrosion.

  • minimizing these problems are available.
    • 1-electroplate the instrument. This affords protection, except
    • on the blade, where use and sharpening remove the plating.
slide99

2- use of rust inhibitors, which are soluble alkaline compounds.

  • 3-is to remove the instruments promptly at the end of the recommended sterilizing period, dry them thoroughly, and place them in the instrument cabinet or on the tray setup.
slide101

1. Amalgam condenser

It is a dental instrument used for compacting silver amalgam while in a plastic state, used for restoring teeth to a natural contour.

Condensers come in single- and double-ended designs. They have various shaped and sized working ends, which may be smooth or serrated.

slide103

2. mouth mirror

mouth mirror or dentist's mirror is an instrument used in dentistry.

The head of the mirror is usually round, and the most common sizes used are the No. 4 and No. 5. A No. 2 is sometimes used when a smaller mirror is needed, such as when working on back teeth with a dental dam in place.

its most important functions are:

allowing indirect vision by the dentist .

  • reflecting light onto desired surfaces.
  • retraction of soft tissue.
slide106

4. others

A. Carvers.

After the amalgam is condensed, it must then be carved to approximately the same original tooth structure.

Carvers have sharp cutting edges that are used to shape, form, or cut tooth anatomy into amalgam restorations.

slide108

B. Burnishers.

When the carving is complete, the dentist may use burnishers.

used to

smooth and polish the restoration.

remove scratches left on the amalgam surface by a carving instrument.

slide110

C. disposable brush

used with etching and bonding procedures associated with composite resins is a disposable brush with a reusable handle.

aiding in good infection control practices.

Disposable brush and handle.

slide111

Thanks

for

attention