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Page 1: Dental operating unit

Introduction to Dental Operating Unit

Prepared by : Umar Ali HamaGarmyan Yawar

Group(D)

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Dental Chair

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Tumbler Holder

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Saliva ejector

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High Volume evacuator

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Syringe

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Curing Light

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Bracket Table

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Opaque glass plate/x-ray viewer

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High speed & Low speed adaptor

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Dental chair control

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Foot Control

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Patient and operator positions

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CONTENTs

• INTRODUCTION

• DENTAL CHAIR AND PATIENT POSTIONS

• OPERATOR POSITIONS

• OPERATING STOOLS

• GENERAL CONSIDERATIONS

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Proper positioning of the patient and operator, illumination and retraction for optimal visibility are fundamental pre requisites to proper dental treatment

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For operative dental procedures , the patient may be seated in one of the following positions:

1. Almost supine

2. Reclined 45 degrees

3. Upright position

Dental chair and patient position

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1. ALMOST SUPINE POSITION:

In this position the chair is tilted so that the patient is almost in a lying down posture

The patient’s head ,knees and feet are approximately at the same level

The head should not be positioned below the feet level as blood pressure increases gradually

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2. RECLINED 45 DEGREE POSITION:

In this position the chair is reclined at 45 degrees so that when the patient is seated, the mandibular occlusal surfaces are almost at 45 degrees to the floor

Once the treatment is over the chair is brought back to upright position so that the patient can leave the chair easily

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POSITONS OF THE OPERATOR

Forearm parallel to the floor

Thighs parallel to the floor

Hip angle of 90 degrees

Seat height positioned low enough so that the heels of your feet touch the floor

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When working from clock positions 9-12:00, feet spread apart so that your legs and the chair base form a tripod which creates a stable position

Avoid positioning your legs behind the patient’s chair

Back of the operator should be always straight

Head erect and should not be bent of drooping

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Operator position:

The main thing which we have to consider is the Operator Position 

Correct positioning of the operator is very important to operator to have good visibility and accessibility to oral cavity.

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FOR A RIGHT HANDED OPERATOR:

1. Right front or 7’o clock position

2. Right or 9’o clock position

3. Right rear or 11’o clock position

4. Direct rear or 12’oclock position

LEFT HANDED OPERATOR'S POSITIONS , 1- 5 O'CLOCK2- 3 O'CLOCK 3- 1 O'CLOCK

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RIGHT FRONT POSITION (7 O'CLOCK) :

1. IT HELPS IN EXAMINATION OF THE PATIENT

2. WORKING AREAS INCLUDE:a) MANDIBULAR ANTERIORb) MANDIBULAR POSTERIOR TEETH

(RIGHT SIDE)c) MAXILLARY ANTERIOR TEETH

3. TO INCREASE THE EASE AND VISIBILITY, THE PATIENT'S HEAD MAY BE TURNED TOWARDS THE OPERATOR.

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RIGHT POSITION (9 O'CLOCK) :

1. IN THIS POSITION,DENTIST SITS EXACTLY RIGHT TO THE PATIENT

2. WORKING AREAS INCLUDE:a) FACIAL SURFACES OF

MAXILLARY RIGHT POSTERIOR TEETH

b) FACIAL SURFACES OF MANDIBULAR RIGHT POSTERIOR TEETH

c) OCCLUSAL SURFACES OF MANDIBULAR RIGHT POSTERIOR TEETH.

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RIGHT REAR POSITION (11 O'CLOCK): 1. IN THIS POSITION, DENTIST SITS

BEHIND AND SLIGHTLY TO THE RIGHT OF THE PATIENT AND THE LEFT ARM IS POSITIONED AROUND PATIENT'S HEAD

2. THIS IS PREFERRED POSITION FOR MOST OF DENTAL PROCEDURES

3. MOST AREAS OF MOUTH ARE ACCESSIBLE FROM THIS POSITION EITHER USING DIRECT OR INDIRECT VISION

4. WORKING AREAS INCLUDE:a) PALATAL AND INCISAL

(OCCLUSAL) SURFACES OF MAXILLARY TEETH

b) MANDIBULAR TEETH (DIRECT VISION).

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DIRECT REAR POSITION (12 O'CLOCK): 1. DENTIST SITS DIRECTLY BEHIND

THE PATIENT AND LOOKS DOWN OVER THE PATIENT'S HEAD DURING PROCEDURE.

2. WORKING AREAS ARE LINGUAL SURFACES OF MANDIBULAR TEETH.

3. THIS POSITION HAS LIMITED APPLICATION.

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SEQUENCE FOR ESTABLISHING POSITION

1ME.ASSUME THE CLOCK POSITION FOR THE TREATMENT AREA

2 MY PATIENT.ESTABLISH PATIENT CHAIR AND HEAD POSITION.

3MY EQUIPMENT.ADJUST THE UNIT LIGHT. PAUSE AND SELF-CHECK THE CLINICIAN, PATIENT, AND EQUIPMENT POSITION.

4MY NONDOMINANT HAND.PLACE THE FINGERTIPS OF MY NONDOMINANT HAND AS SHOWN IN THE ILLUSTRATION FOR THE CLOCK POSITION.

5MY DOMINANT HAND.PLACE THE FINGERTIPS OF MY DOMINANT HAND AS SHOWN IN THE ILLUSTRATION FOR THE CLOCK POSITION.

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• WHEN WORKING ON ANTERIOR SEXTANTS, YOUR LEFT HAND (NON-DOMINANT HAND) AND YOUR RIGHT HAND (DOMINANT HAND) ARE POSITIONED ON OPPOSITE SIDES OF THE PATIENT’S MOUTH.

• ANTERIOR SURFACES TOWARD MY NON-DOMINANT HAND—THE COLORED ANTERIOR SURFACES IN THIS ILLUSTRATION.

• ANTERIOR SURFACES AWAY FROM MY NON-DOMINANT HAND—THE WHITE ANTERIOR SURFACES IN THIS ILLUSTRATION.

POSITIONING TERMINOLOGY

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POSTERIOR ASPECTS FACING TOWARD ME—THE COLORED POSTERIOR SURFACES IN THIS ILLUSTRATION.

• MAXILLARY RIGHT POSTERIOR SEXTANT, FACIAL SURFACES• MAXILLARY LEFT POSTERIOR SEXTANT, LINGUAL SURFACES• MANDIBULAR RIGHT POSTERIOR SEXTANT, FACIAL SURFACES• MANDIBULAR LEFT POSTERIOR SEXTANT, LINGUAL SURFACES

POSITIONING TERMINOLOGY

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POSTERIOR ASPECTS FACING AWAY FROM ME—THE COLORED POSTERIOR SURFACES IN THIS ILLUSTRATION.

• MAXILLARY LEFT POSTERIOR SEXTANT, FACIAL SURFACES• MAXILLARY RIGHT POSTERIOR SEXTANT, LINGUAL SURFACES• MANDIBULAR LEFT POSTERIOR SEXTANT, FACIAL SURFACES• MANDIBULAR RIGHT POSTERIOR SEXTANT, LINGUAL SURFACES

POSITIONING TERMINOLOGY

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ARCH TREATMENT AREA CLOCK POSITION

HEAD POSITION

MANDIBULAR ARCH

ANTERIOR SURFACES TOWARD MY NON-DOMINANT HAND

8–9 SLIGHTLY TOWARD, CHIN DOWN

ANTERIOR SURFACES AWAY FROM MY NON-DOMINANT HAND

12 SLIGHTLY TOWARD, CHIN DOWN

MAXILLARY ARCH

ANTERIOR SURFACES TOWARD MY NON-DOMINANT HAND

8–9 SLIGHTLY TOWARD, CHIN UP

ANTERIOR SURFACES AWAY FROM MY NON DOMINANT HAND

12 SLIGHTLY TOWARD, CHIN UP

MANDIBULAR ARCH

POSTERIOR ASPECTS FACING TOWARD ME (RIGHT FACIAL AND LEFT LINGUAL)

9 SLIGHTLY AWAY, CHIN DOWN

POSTERIOR ASPECTS FACING AWAY FROM ME (RIGHT LINGUAL AND LEFT FACIAL)

10–11 TOWARD, CHIN DOWN

MAXILLARY ARCH

POSTERIOR ASPECTS FACING AWAY FROM ME (RIGHT LINGUAL AND LEFT FACIAL)

10–11 TOWARD, CHIN UP

POSTERIOR ASPECTS FACINGTOWARD ME (RIGHT FACIAL AND LEFT LINGUAL)

9 SLIGHTLY AWAY, CHIN UP

POSITION FOR THE RIGHT-HANDED

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Operator stools:

The design of the stool is important.

It should be sturdy and well balanced to prevent tipping/gliding away from dental chair

It should be well padded with cushion edges and should be adjusted up and down

A well designed stool increases operator comfort and reduces fatigue

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LIGHTING;

The operator should be well illuminated either by natural or artificial light.

If the light is kept too close , it impairs the physical movement of operator & also increases patient discomfort due to heat production.

If the light is kept far away, it reduces the illumination.

As a rule for mandibular arch the light is kept in a higher position & for maxillary arch it is kept in a lower position.

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general considerations:

The patient’s head should be rotated according to need of operator without hesitation

During working maxillary occlusal surfaces should be perpendicular to the floor and for mandibular occlusal surface should be 45 degrees

The operator should maintain space between the patient as while reading a book

There should be reduced contact with that of patient

a) The operator should never rest his hand on patient’s face

b) The chest of patient should never be used as trays to keep instruments

The left hand should be kept free to retract using the mouth mirror

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DON’TS:

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INFECTION CONTROL

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contents INTRODUCTION

TRANSMISSION OF INFECTION

MODE OF TRANSMISSION

MODE OF INFECTION CONTROL

INFECTION CONCERN IN DENTISTRY

OBJECTIVES OF INFECTION CONTROL

PERSONAL BARRIER PROTECTION

OPERATORY ASEPSIS

DISINFECTION

INSTRUMENT HANDLING & CLEANING

STERILIZATION

MONITORS OF STERILIZATON

CLINICAL WASTE DISPOSAL

STORAGE OF STERILIZED ITEMS

HANDPIECE ASEPSIS

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introduction Microorganisms are ubiquitous.

Since pathogenic microorganisms cause contamination, infection and decay, it becomes necessary to remove or destroy them from materials and areas.

This is the objective of infection control and sterilization.

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definitions INFECTION CONTROL – Also called “exposure control

plan” by OSHA is a required office program that is designed to protect personnel against risks of exposure to infection.

STERILIZATION: Use of a physical or chemical procedure to destroy all microorganisms including substantial numbers of resistant bacterial spores.

Sterilization means the destruction of all life forms. (Ronald B Luftig)

Sterilization is the process of killing or removing all viable organisms. (MIMS – PLAYFAIR)

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STERILE: Free from all living microorganisms; usually

described as a probability (e.g., the probability of a surviving microorganism being 1 in 1 million).

DISINFECTION: Destruction of pathogenic and other kinds of microorganisms by physical or chemical means. Disinfection is less lethal than sterilization, because it destroys the majority of recognized pathogenic microorganisms, but not necessarily all microbial forms (e.g., bacterial spores).

Disinfection is a process of removing or killing most, but not all, viable organisms.

(MIMS-PLAYFAIR)

Disinfection refers to the destruction of pathogenic organisms.

(Ronald B Luftig)

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DISINFECTANT: A chemical agent used on inanimate objects to destroy virtually all recognized pathogenic microorganisms, but not necessarily all microbial forms (e.g., bacterial endospores).

ASEPSIS: prevention of microbial contamination of living tissues or sterile materials by excluding, removing or killing microorganisms.

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Transmission of infection

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MODES OF TRANSMISSION:

Six links in chain of transmission of infection

Chain of infectio

n

Infectious agent

Reservoirs

Portal of exit

Means of transmissi

on

Portal of entry

Susceptible host

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Be Aware of Cross-infection!!!

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OBJECTIVES OF INFECTION CONTROL

Reduce

Implement

Simplify

Protect

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STRATEGY TO ACHIEVE INFECTION CONTROL

Screening

PPE(personal protection equipment)

Aseptic techniques

Sterilization & disinfection

disposal

Laboratory asepsis

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PREPROCEDURAL MOUTH RINSE

How

Where

When

A commercial mouthrinse containing 0.05 percent CPC when used as a preprocedural mouthrinse was equally effective as CHX in reducing the levels of spatter bacteria generated during ultrasonic scaling.

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HAND HYGIENE

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For routine dental examination procedures, hand washing is

achieved by using either a plain or antimicrobial soap and water.

The purpose of surgical hand antisepsis is to eliminate transient flora and reduce resident flora to prevent introduction of organisms in the operative wound, if gloves become punctured or torn.

At the beginning of a routine treatment period, watches and jewelry must be removed and hands must be washed with a suitable cleanser.

Hands must be lathered for at least 10 seconds, rubbing all surfaces and rinsed.

Clean brushes can be used to scrub under and around the nails.

Must be repeated at least once to remove all soil.

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PERSONAL BARRIER PROTECTION

Personal protective equipment (PPE), or barrier precautions, are a major component of Standard precautions.

PPE is essential to protect the skin and the mucous membranes of personnel from exposure to infectious or potentially infectious materials.

The various barriers are gloves, masks, protective eye wear, surgical head cap & overgarments

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gloves

Types:

1. Latex gloves

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Vinyl gloves

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Nitrile gloves

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Neoprene

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General purpose utility gloves

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Steps in gloving

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CONTACT DERMATITIS AND LATEX HYPERSENSITIVITY Contact dermatitis is classified as

1. Irritant

2. Allergic.

Latex hypersensitivity

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PRECAUTIONS TAKEN FOR LATEX ALLERGIC PATIENTS

Be aware that latent allergens in the ambient air can cause respiratory or anaphylactic symptoms among persons with latex hypersensitivity.

Patients with latex allergy can be scheduled for the first appointment of the day to mini- mize their inadvertent exposure to airborne latex particles.

Have emergency treatment kits with latex free products available at all times.

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masks

Types:

1. Surgical masks (required to have

fluid-resistant properties).

2. Procedure/isolation masks

Made up from a melt blown placed between non-woven fabric

Layers of a Mask

1. an outer layer

2. a microfiber middle layer - filter large wearer-generated particles

3. a soft, absorbent inner layer - absorbs moisture.

Available in 2 sizes: regular and petite.

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N95 PARTICULATE RESPIRATOR

National Institute for Occupational Safety and Health (NIOSH) introduced a rating system which identifies the abilities of respirators to remove the most difficult particles to filter, referred to as the most penetrating particle size (MPPS), which is 0.3µm in size.

The “N” means “Not resistant to oil”.

N95: captures at least 95% of particles at MPPS.

N99: captures 99% of particles at MPPS.

N100: captures 99.97% of particles at MPPS.

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Eye wear

CAUSES OF EYE DAMAGE:

1. Aerosols and spatter may transmit infection

2. Sharp debris projected from mouth while using air turbine handpiece, ultrasonic scaler may cause eye injury.

3. Injuries to eyes of patients caused by sharp instruments especially in supine position

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Over garmentsGown type Situation and Rationale

Cotton/linen, reusable or disposable, long-sleeved isolation gowns

Use if contamination of uniform or clothing is likely or anticipated

Fluid resistant isolation gown or plastic apron over isolation gown 

Use if contamination of uniform or clothing from significant volumes of blood or body fluids is likely or anticipated (fluids may wick through non-fluid resistant reusable or disposable isolation gowns)

Fluid impervious gowns e.g., Gortex®  

Use if extended contact or large volume exposure (e.g., large volume blood loss during resuscitation of MVA victim or surgical assist)

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Footwear

Most hospitals have their own policies regarding footwear.

Footwear with open heels and/or holes across the top can increase the risk of harm to the person wearing them due to more direct exposure to blood/body fluids or of sharps being dropped for examples.

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PRECAUTIONS TO AVOID INJURY EXPOSURE

Engineering controls are the primary method to reduce exposures to blood from sharp instruments and needles

Work-practice controls establish practices to protect personnel whose responsibilities include handling, using, or processing sharp devices.

Sharp end of instruments must be pointed away from the hand

Avoid handling large number of sharp devices.

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OPERATORY ASEPSIS

In the dental operatory, environmental surfaces (i.e., a surface or equipment that does not contact patients directly) can become contaminated during patient care. Certain surfaces, especially ones touched frequently (e.g., light handles, unit switches, and drawer knobs) can serve as reservoirs of microbial contamination, although they have not been associated directly with transmission of infection to either personnel or patients.

Transfer of microorganisms from contaminated environmental surfaces to patients occurs primarily through personnel hand contact

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CDC(center for Disease control)

classification

Category Definition Dental instrument or item

Critical Penetrates soft tissue, contacts bone, enters into or contacts the blood- stream or other normally sterile tissue. 

Surgical instruments, periodontal scalers, scalpel blades, surgical dental burs

Semicritical Contacts mucous membranes or nonintact skin; will not penetrate soft tissue, contact bone, enter into or contact the bloodstream or other normally sterile tissue.

Dental mouth mirror, amalgam condenser, reusable dental impression trays, dental handpieces

Noncritical Contacts intact skin. Radiograph head/cone, blood pressure cuff, facebow, pulse oximeter

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DISINFECTION

Disinfection is always at least a two-step procedure:

The initial step involves vigorous scrubbing of the surfaces to be disinfected and wiping them clean.

The second step involves wetting the surface with a disinfectant and leaving it wet for the time prescribed by the manufacturer.

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The ideal disinfectant has the following properties:

1. Broad spectrum of activity

2. Acts rapidly

3. Non corrosive

4. Environment friendly

5. Is free of volatile organic compounds

6. Nontoxic & nonstaining

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High-level disinfection: Disinfection process that inactivates vegetative bacteria, mycobacteria, fungi, and viruses but not necessarily high numbers of bacterial spores.

Intermediate-level disinfection: Disinfection process that inactivates vegetative bacteria, the majority of fungi, mycobacteria, and the majority of viruses (particularly enveloped viruses) but not bacterial spores.

Low-level disinfectant: Liquid chemical germicide. OSHA requires low-level hospital disinfectants also to have a label claim for potency against HIV and HBV.

Gigasept which contains succindialdehyde and dimethoxytetrahydrofuran are used for disinfection of plastic and rubber materials eg: dental chair

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INSTRUMENT WASHER

Instrument washers use high-velocity hot water and a detergent to clean instruments.

These devices require personnel to either place instruments in a basket or to use instrument cassettes during the cleaning and drying cycles.

Types:

1. Counter top model

2. Resembles a kitchen dish washer

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thermal disinfectors

These devices may look like the instrument washers described above; however, there is one important difference.

The high temperature of the water and chemical additives in these devices cleans and disinfects the instruments.

Instruments can be more safely handled, and if the dental healthcare professional were to sustain a puncture injury, it would not require the follow-up that a contaminated exposure requires

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NEW SOLAR ENERGY TECHNOLOGY: KILLING GERMS ON MEDICAL, DENTAL INSTRUMENTS

“It is completely off-grid, uses sunlight as the energy source, is not that large, kills disease-causing microbes effectively and relatively quickly and is easy to operate.

Halas and colleagues have prototypes of two solar steam machines.

1. The autoclave for sterilizing medical and dental instruments.

2. Autoclave for disinfecting human and animal wastes

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INSTRUMENT PROCESSING

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Selection of packaging materials for sterilizationSteam sterilization Papers, cellulose, cotton/polyester cloths,

window packs, perforated rigid containers with bacterial filters, glass containers for liquids

Dry heat (hot air oven) Metal canisters and tubes of aluminium foil, glass tubes, bottles

ETO Paper & Plastic, perforated rigid containers with bacterial filters

Low temperature steam Paper, cloth

Radiation sterilization Polyethylene, PVC, polypropylene, foil.

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STERILIZATION Stages for instrument sterilization:

1. Presoaking

2. Cleaning

3. Corrosion control and lubrication

4. Packaging

5. Sterilization

6. Handling sterile instruments

7. Storage

8. Distribution

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Agents used in sterilization Physical agents:

1. Sunlight

2. Drying

3. Dry heat: flaming, incineration, hot air

4. Moist heat: pasteurization, boiling, steam under pressure, steam under normal pressure.

5. Filtration: candles asbestos pads, membranes

6. Radiation

7. Ultrasonic and sonic vibrations

Chemical agents:

1. Alcohols: ethyl, isopropyl, trichlorobutanol

2. Aldehydes: formaldehyde, glutaraldehyde

3. Dyes

4. Halogens

5. Phenols

6. Surface-active agents

7. Metallic salts

8. Gases: ethylene oxide, formaldehyde, beta propiolactone.

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The four accepted methods of sterilization are :

Steam pressure sterilization (autoclave)

Chemical vapor pressure sterilization- (chemiclave)

Dry heat sterilization (dryclave)

Ethylene oxide sterilization

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STEAM PRESSURE STERILIZATION (AUTOCLAVING)

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Advantages of Autoclaves.

1. Autoclaving is the most rapid and effective method for sterilizing cloth surgical packs and towel packs.

2. Is dependable and economical

3. Sterilization is verifiable.

Disadvantages of Autoclaves.

1. Items sensitive to the elevated temperature cannot be autoclaved.

2. Autoclaving tends to rust carbon steel instruments and burs.

3. Instruments must be air dried at completion of cycle

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TRIPLE VACUUM AUTOCLAVE

A triple vacuum autoclave is set up/function in a similar fashion to a negative pressure displacement.

This is repeated three times, hence the name "triple vacuum" autoclave. This type of autoclave is suitable for all types of instruments and is very versatile

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CHEMICAL VAPOR PRESSURE STERILIZATION (chemiclaving)

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An unsaturated chemical vapor system , also called harvey chemiclave.

Advantages

1. Carbon steel and other corrosion-sensitive instruments are said to be sterilized without rust.

2. Relatively quick turnaround time for instruments.

3. Load comes out dry.

4. Sterilization is verifiable.

Disadvantages

1. Items sensitive to the elevated temperature will be damaged. Vapor odor is offensive, requires aeration.

2. Heavy cloth wrappings of surgical instruments may not be penetrated to provide sterilization.

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DRY HEAT STERILIZATION

Conventional Dry Heat Ovens

Short-Cycle, High-Temperature

Dry Heat Ovens

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Advantages of Dry Heat Sterilization

1. Carbon steel instruments and burs do not rust, corrode, if they are well dried before processing.

2. Industrial forced-draft hot air ovens usually provide a larger capacity at a reasonable price.

3. Rapid cycles are possible at high temperatures.

4. Low initial cost and sterilization is verifiable.

Disadvantages of Dry Heat Sterilization

1. High temperatures may damage more heat-sensitive items, such as- rubber or plastic goods.

2. Sterilization cycles are prolonged at the lower temperatures.

3. Must be calibrated and monitored

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ETHYLENE OXIDE STERILIZATION (ETO)

MOBILE FUMIGATOR

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Advantages:

1. Operates effectively at low temperatures

2. Gas is extremely penetrative

3. Can be used for sensitive equipment like handpieces.

4. Sterilization is verifiable

Disadvantages:

1. Potentially mutagenic and carcinogenic.

2. Requires aeration chamber ,cycle time lasts hours

3. Usually only hospital based.

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Gamma radiation The Nature of Gamma Radiation A form of pure energy that is generally

characterized by its deep penetration and low dose rates, Gamma Radiation effectively kills microorganisms throughout.

Benefits of Gamma Radiation include:

1. precise dosing

2. rapid processing

3. uniform dose distribution

4. system flexibility

5. dosimetric release–the immediate availability of product after processing.

Penetrating Sterilization: Even with High-Density Products Gamma Radiation is a penetrating sterilant.

Substantial Decrease in Organism Survival: Gamma Radiation kills microorganisms by attacking the DNA molecule.

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Uv radiation

The wavelength of UV radiation ranges from 328 nm to 210 nm (3280 A to 2100 A). Its maximum bactericidal effect occurs at 240–280 nm

Inactivation of microorganisms results from destruction of nucleic acid through induction of thymine dimers.

UV radiation has been employed in the disinfection of drinking water , air, titanium implants, and contact lenses.

The application of UV radiation in the health-care environment (i.e., operating rooms, isolation rooms, and biologic safety cabinets) is limited to destruction of airborne organisms or inactivation of microorganisms on surfaces

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Flash sterilization

“Flash” steam sterilization was originally defined by Underwood and Perkins as sterilization of an unwrapped object at 1320C for 3 minutes at 27-28 lbs. of pressure in a gravity displacement sterilizer.

Currently, the time required for flash sterilization depends on the type of sterilizer and the type of item (i.e., porous vs non-porous items).

Uses:

Flash sterilization is considered acceptable for processing cleaned patient-care items that cannot be packaged, sterilized, and stored before use.

It also is used when there is insufficient time to sterilize an item by the preferred package method.

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OTHER STERILIZATION METHODS

Dry-Heat Sterilizers

Liquid Chemicals

Performic Acid

Filtration

Microwave

Glass Bead “Sterilizer”

Vaporized Hydrogen Peroxide

Formaldehyde Steam

Gaseous Chlorine Dioxide

Vaporized Peracetic Acid

Infrared radiation

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NEW METHODS OF STERILIZATION

Various new methods of sterilization are under investigation and development.

Peroxide vapor sterilization - an aqueous hydrogen peroxide solution boils in a heated vaporizer and then flows as a vapor into a sterilization chamber containing a load of instruments at low pressure and low temperature

Ultraviolet light - exposes the contaminants with a lethal dose of energy in the form of light. The UV light will alter the DNA of the pathogens. Not effective against RNA viruses like HIV.

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ozone Ozone sterilization is the newest low-temperature

sterilization method recently introduced in the US and is suitable for many heat sensitive and moisture sensitive or moisture stable medical devices

Ozone sterilization is compatible with stainless steel instruments.

Ozone Parameters • The cycle time is approximately 4.5 hours, at a temperature of 850F – 940F.(nearly 23 C)

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STORAGE AND CARE OF STERILE INSTRUMENTS

Storage areas should be dust proof, dry, well ventilated and easily accessible for routine dental use.

Sterile materials should be stored atleast 8-10 inches from the floor, atleast 18 inches from the ceiling, and atleast 2 inches from the outside walls.

Items should be positioned so that packaged items are not crushed, bent, crushed, compressed or punctured.

Items are not stored in any location where they can become wet.

Outside shipping containers and corrugated cartons should not be used as containers in sterile storage areas.

Ultra violet chambers and formalin chambers are now commonly used for storage of instruments.

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MONITORS OF STERILIZATION

There are 3 methods of monitoring sterilization:

Mechanical techniques

Chemical indicators

1. Internal

2. External

Biological indicators

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STERILIZATION METHOD SPORE TYPE INCUBATION TEMPERATURE

AUTOCLAVE Bacillus stearothemophilus 56°C

CHEMICAL VAPOR

DRY HEAT Bacillus subtilis 37°C

ETHYLENE OXIDE

Gamma radiation B. Pumilus E601 370C

Sterilization monitoring has four components:

1. a sterilization indicator on the instrument bag, stamped with the date it is sterilized,

2. daily color-change process-indicator strips,3. weekly biologic spore test, and 4. documentation notebook.

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HANDPIECE ASEPSIS

Oral fluid contamination problems of rotary equipment and especially the high-speed handpiece involve:

contamination of hand-piece external surfaces and crevices,

turbine chamber contamination that enters the mouth,

water spray retraction and aspiration of oral fluids into the water lines of older dental units

growth of environmental aquatic bacteria in water lines

exposure of personnel to spatter and aerosols generated by intraoral use of rotary equipment.

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HANDPIECE SURFACE CONTAMINATION CONTROL

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CLINICAL WASTE DISPOSAL Red: Anatomical waste

Yellow: waste which requires disposal by incineration only

Black: Domestic waste minimum treatment/disposal required is landfill, municipal incineration.

Blue: medicinal waste for incineration

White: amalgam waste for recovery.

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REFERENCES: Sturdevent’s Art & Science of operative Dentistry. Clinical Operative dentistry- Ramya Raghu & Raghu Srinivasan Internet sources Pathways of the pulp, 9th edition, armamentarium & sterilization. Cohen Operative dentistry, infection control, 4th edition, sturdevent. Grossmans endodontic practice, 11th edition, instrument sterilization. Textbook of microbiology, sterilization and disinfection, 7th edition,

Ananthanarayan Textbook of clinical periodontology, Newman, Takei, Carranza, 11th

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