CONTENTS

Introduction

Steps in development of infection

Types of infection in dentistry

Modes of disease transmission

Routes of entry of microorganism into our body

Pathway of infection transmission in dental office

Agents of sterilisation

Universal precaution

Methods of infection control

Bioaerosols in dental office

Universal precautions

Standard precautions

Operation theater setup and protocols

Surgical scrub

Protective attire and barrier technique

Draping a patient and patient position

Gowing before surgery and handling of intrument

Cleaning of instrument and disinfection of dental labs and radiographic units

Types of mask and gloves

Gloving of hands

Conclusion

Reference

INTRODUCTION

Dental environment is associated with significant risk of exposure to various

microorganisms. Many infectious(blood, saliva) bacteriemia or viremia associated

with systemic infections. Dental patients and dental surgeons exposed to variety of

microorganisms via blood ,oral or respiratory secretions. (cytomegalovirus, hepatitis

B virus, hepatitis C virus, herpes simplex virus type 1 and type 2, HIV,

mycobacterium tuberculosis, staphylococci, streptococci and other viruses and

bacteria- specially those that infect the upper respiratory tract.) Infections may be

transmitted in the dental operatory through direct Contact - With the blood, oral

fluids, other secretions.

Indirect Contact- Contaminated instruments, operatory equipment or environmental

surfaces or contact with air borne contaminants present in either droplet spatter or

aerosols or oral or respiratory fluids. Infection via these routes require that all of the

three conditions be present.

Steps in Development of Infection

Source of microorganisms

Spread of microorganism to a new person

Escape of microorganism from a source

Entry of microorganism into the person

Infection(survival and growth of microorganism)

Damage to the body

Types of Infection

1. Endogenous infection

Diseases that originate within the individuals body and are not transmitted

from another infected individual.

E.g- metabolic disorders

2. Exogenous infection

Diseases originating from outside an individuals body. These are caused by

pathogenic microorganisms that invade the body such as radiation, chemicals,

temperature.

3. Nosocromial infection

Are acquired by a patient in hospital or long term care facility. Common

examples are staphylococcal infections and pseudomonas. Most common

causes are improper hygienic methods and break in the chain of sterility.

4. Oppurtunistic infection

They occur when the bodys ability to resist disease is weakened. These

opportunistic infections do not infect persons with intact immune system. Ex:

Kaposi sarcoma

Stages of Infection

Incubation stage:-

Interval between the exposure to pathogenic microorganism and the first appearance

of signs and symptoms of the disease.

Prodomal stage:-

Indicates the onset of disease and is characterized by symptom

Acute stage:-

Disease has reached the peak and signs and symptoms are fully developed and

differentiated from other specific symptoms.

Declining stage:-

Patient signs and symptoms has begin to decline.

Convelescent stage:-

Recovery and recuperation of the disease has started to occur and patient begins to

regain its health.

Bioaesosol in Dental Clinic

Bio aerosols are living microbes that travel via a mist and may contain bacteria,

viruses, molds, fungi or yeast. These air borne microorganisms can be found inside a

dental office, coverings, surfaces etc. because aerosols are generally invisible, most

individuals are unaware of their presence. Alginate powder mixed with water can

become a aerosol and can cause bronchial irritation if inhaled

.

Air turbine hand pieces, scalars, air water sprays, rotary instruments, dental lathes all

have the potential of producing aerosols contaminated with microorganisms.Normal

oral flora, bacterial plaque, calculus, respiratory disease, caries, herpetic lesions,

Tuberculosis and intraoral infections are potential intra oral sources of infections

caused due to inhalation of BIO AEROSOLS.

Agents Use in Sterilisation

I. Physical Agents

Sunlight

Drying:- Flaming, Incineration, Hot air oven

Moist heat :- Pasteurisation, Boiling,Steam under pressure ,Steam under

pressure

Filtration:- Candles, Asbestose, Pads , Membrane

Radiation

Ultrasonic and sonic

II. Chemical Agents:

Alcohol :- ethyl alcohol , isopropile alcohol, trichlorobutanol

Aldehydes :- formaldehyde, glutaraldehyde

Dyes

Phenols

Surface active agents

Metallic salt

Sunlight

Sunlight Possesses appreciable bactericidal activity

Action is primarily due to UV-rays

Mostly used in tropical countries

Drying

Spores are Moisture is essential for growth of bacteria.

4/5th wt. not affected by drying.

Heat

Most prominent anti microbial agent

MOIST HEAT DRY HEAT

Pasteurization Flaming

Boiling Incineration

Steam under pressure Hot air

Tyndalization

Dry Heat Kills by Oxidation Effect

1. FLAMING:- Scalpels,blades,needles,mouth of culture tubes,botteles,glass

slides and cover slips are sterlized by this method.

2. INCINERATION:-Effective method for rapidly destroying contaminated

materials such as soiled dressings and pathological material, etc.

3. HOT AIR OVEN:-

o holding period:-

At 160 for 2hrs

At 170 for 1hr

At 150 for 2&1/2hrs

Hot Air Oven:

Dry heat penetrates less and less effective than moist heat.

Higher temperatures and longer time is required.

So it is essential that hot air oven should have time lock on the door.

Materials sterlized- All glass syringes,test tubes,petri dishes and flasks,metal

instruments such as forceps,scissors,scalpels,sealed material such as

oils,greeses and dry powder.

Autoclave

Moist Heat: Steam Under Pressure

Autoclave: Chamber which is filled with hot steam under pressure. Preferred method of

sterilization, Temperature of steam reaches 121oC at twice atmospheric pressure.

Holding Time:-

At 15psi 121C for 15mins

At 15psi 126C for 10 mins

At 15 psi 134C for 3mins

Most effective when organisms contact steam directly or are contained in a small

volume of liquid. All organisms and endospores are killed within 15 minutes. Suitable

for sterilization of Culturemedia, Aqueous solutions, dressing material, linen, gloves,

etc.

Control Test:-Thermo couple, Browns test, bowie-dick test, steoro thermophilus

spores Require more time to reach center of solid or large volumes of liquid.

Sonic Ultrasonic

Universal Precautions

ADA recommends that blood and body fluid precautions be used consistently for all

Patients. This extension of blood and body fluid precautions referred as Universal

Precautions must be observed routinely in the care of all patients.

Standard Principles of Infection Control/ Universal Precautions

Hand hygiene and skin care.

Protective Clothing.

Safe Handling of Sharps (including Sharps Injury Management).

Spillage Management.

All blood and body fluids are potentially infectious and precautions are

necessary to prevent exposure to them.

A disposable apron and latex or vinyl gloves should always be worn when

dealing with excreta, blood and body fluids.

Everyone involved in providing care in dental practice should know and apply

the standard principles of hand decontamination, the use of protective

clothing, the safe disposal of sharps and body fluid spillages.

Each member of staff is accountable for his/her actions and must follow safe

practices.

OSHA (Occupational Safety and Health Administration) For Dentistry

Provide Hepatitis B immunization to employees without charge within 10 days

of employment.

Require that universal precautions be observed to prevent contact with blood

and other potentially infectious material. Saliva is considered to be blood

contaminated body fluid in relation to dental treatments.

Implementing engineering controls to reduce production of contaminated

spatters, mists and aerosols.

Implement work practice control precautions to minimize splashing, spatter or

contact of bare hands with contaminated surfaces. Provide facilities and

instructions for washing hands after removing gloves and for washing skin

immediately or as soon as feasible after contact with blood or potentially

infectious materials. Prescribe safe handling of needles and other sharp items.

Contaminated sharps are termed as regulated waste and must be discarded in

hard walled containers.

Contaminated equipment that has to be serviced must first be decontaminated

or a bio hazard label must be put on it.

Personnel handling sharps must not reach out with his hands inside the

container.

Provide laundering of PPE(Personal Protective Equipment) to the employees

without any cost.

Provide vaccination for all employees under no cost against all infectious that

could be prevented by immunization. Some of the infections that require

immunization in the dental setting are HEPATITIS, RUBELLA, MEASLES.

MUMPS, INFLUENZA, TETANUS.

Prescribe disposable or single use needles, sharps and dispose them as soon as

feasible in a hard walled leak proof containers that are closable. Containers must be

red or bear a biohazard label. Teeth must be discarded into sharp containers.

Contaminated reusable sharp instruments must not be stored or processed in a manner

that requires employees to reach hands into containers to retrieve them. Prohibit

eating, drinking, handling contact lenses etc in contaminated environments. Ban

storage of foods and drinks in refrigeration or other spaces where blood or infectious

materials are stored.

Place blood and contaminated specimen to be transported into a suitable closed

container that prevents leakage. Provide PPE to employees and clear directions for

use of universal precautions. Ensure the correct use of PPE. As soon as feasible the

working surface and environment must be sanitized after treatment. Provide a written

schedule for cleaning.

Surgical Scrub

Surgical hand washing destroys transient organisms and reduces resident flora before

surgical or invasive procedures.At the start of a session, an aqueous antiseptic

detergent solution is applied to moistened hands and forearms for approximately 2

minutes. The nails are scrubbed and a manicure stick can be used to remove dirt from

beneath the nail. The disinfection process must be thorough and systematic, covering

all aspects of the hands and forearms. The procedure should take 3 to 5 minutes.

Preparations currently available are 4% chlorhexidine and 7.5% povidone-iodine

solution. The hands must be thoroughly dried with a sterile towel prior to donning

sterile gloves.

The purpose of surgical hand scrub is to eliminate transient flora and reduce resident

flora for the duration of the procedure to prevent introduction of micro-organisms in

the operative wound.

Hands must be washed:

Before and after each work shift or work break. Remove jewellery (rings)

Before and after physical contact with each patient.

After handling contaminated items such as dressings.

Before putting on, and after removing, protective clothing including gloves

After using the toilet, blowing your nose or covering a sneeze

Whenever hands become visibly soiled

Before eating, drinking or handling food and before and after smoking.

An Effective Hand Washing Technique Involves Three Stages:

A. Preparation

Before washing hands, all wrist and, ideally, hand jewellery should be

removed. Cuts and abrasions must be covered with waterproof dressings.

Fingernails should be kept short, clear and free from nail polish. Hands should

be wet under tepid running water before applying liquid soap or an

antimicrobial preparation.

B. Washing and Rinsing

Wet the hands under running water. Apply the hand wash solution ensuring

that it comes into contact with all of the surfaces of the hand. The hands must

be rubbed together vigorously for a minimum of 10-15 seconds, paying

particular attention to the tips of the fingers, the thumbs and the areas between

the fingers. Hands should be rinsed thoroughly. When decontaminating hands

use an alcohol hand rub, hands should be free from dirt and organic material.

The hand rub solution must come into contact with all surfaces of the hand.

The hands must be rubbed together vigorously, paying particular attention to

the tips of the fingers, the thumbs and the areas between the fingers, until the

solution has evaporated and the hands are dry.

C. Drying

This is an essential part of hand hygiene. Dry hands thoroughly using good

quality paper towels. In clinical settings, disposable paper towels are the

method of choice because communal towels are a source of cross-

contamination. Store paper towels in a wall-mounted dispenser next to the

washbasin, and throw them away in a pedal operated domestic waste bin. Do

not use your hands to lift the lid or they will become re-contaminated.

Protective Attire and Barrier Techniques Gloves for Protection

For protection of personnel and patients medical gloves must be worn by the dentist

when there is potential for contacting blood, blood contaminated saliva, or mucous

membranes. Non sterile gloves are suitable for examinations and sterile gloves are

suitable for any surgical procedures. Before treatment of each patient, dentist should

wash their hands and put on a new gloves, and after treatment should discard the

gloves and wash their hands.

Surgical gloves should not be washed, disinfected, or sterilized for reuse as by doing

these procedures gloves may cause WICKING i.e. penetration of liquids through

undetected holes in the gloves. Use of chemical solutions, heat treatment, autoclaving

may cause deterioration of gloves.

Steps in Waring Gloves

When gloves are torn, cut or punctured, they should be removed as soon as patient

safety permits. Dentist then should wash their hands thoroughly and reglove to

complete the dental procedure. Dentist who have exudative lesions or weeping

dermatitis, particularly on the hands should refrain from all direct patient care and

handling dental patient care equipment until the condition resolves

Patient Care Glove:-

Sterile Latex Surgial Gloves

Sterile Neoprine Surgical Gloves

Sterile Styrene Gloves

Sterile Copolymer Gloves

Latex Examination Gloves

Vinyl Examination Gloves

Nitrile Examination Gloves

Polyurethane Gloves

Powderless Gloves

Flavored Gloves

Lowprotein Gloves

Utility Gloves:-

Heavy Latex Gloves

Heavy Nitrile Gloves

Thin Copolymer Gloves

Thin Plastic Gloves

Masks, Face Shields, Eye Wear

Chin length plastic face shields, surgical masks and protective eye wear should be

worn when splashing or spattering of blood or other body fluids is likely to come in

contact. When a mask is used it should be changed between patients or during patient

treatment if it becomes moist or wet. Face shields and eye wear should be washed

with a cleaning agent regularly.

Protective Clothing

Protective clothing such as reusable or disposable gowns, lab coats or uniforms must

beworn when clothing is likely to be soiled with blood or body fluids. Reusable

protective attire can be washed according to the manufacturers instructions. Protective

clothing should be changed once daily or is visibly soiled. These attire should be

removed once the dentist leaves the dental Office.

Use and Care of Sharp Instruments

Sharp instruments like needles, scalpel blades, surgical instruments contaminated with

patient saliva and blood should be considered as potentially infected and handled with

care to prevent injuries. Used needles should never be recapped or otherwise

manipulated using both hands, or any other technique that involves directing the point

of a needle toward any part of the body. Either a one handed scoop technique or a

mechanical device holding the needle sheath should be employed. Used disposable

syringes, needles, scalpels, sharp instruments must be placed in appropriate puncture

resistant containers. Bending or breaking needles requires unnecessary manipulation

and thus is not recommended

Clinical sharps should be single-use only.

Do not re-sheath a used needle - if this is necessary a safe method - for

example, a resheathing device - must be used .

Discard sharps directly into a sharps container immediately after use and at the

point of use .

Carry sharps containers by the handle - do not hold them close to the body .

Never leave sharps lying around .

Do not try to retrieve items from a sharps container.

Lock the container when it reaches the fill-line, using the closure mechanism.

Place damaged sharps containers inside a larger sharps container.

Operation Theatre Protocols

ASEPTIC TECHNIQUES

Touching as few surfaces as possible

Minimising of dental Aerosols & splatter

High volume evacuation

Saliva ejectors

Use of the rubber dam

Pre-procedure mouth rinse

Use of disposables

Housekeeping & cleaning

Other aseptic techniques

Operation Theatre Set Up

Operating room should have 2 sets of doors.

Operation theater ceiling, walls & flooring should be disinfected regularly.

Operation theater access should be restricted to O T personnel only.

Operation theaters are disinfected by fumigation.

Operation theater personnel should do a special scrub & dressing before

entering to O T.

Principles in Design Of Operation Theater:-

A. Outer Reception Area Includes:-

The reception office.

The reception waiting room for patients & relatives.

An area for trolleys storage .

An area of hanging gowns for relatives & parents.

B. A Clean Zone:-

Which is wide clean corridor giving access to anesthetic room ,recovery room,

clean storage area, emergency autoclave , x-ray machine

The Operating Theater

OT should have a double door entrance from anesthetic room & a double door

entrance to the clean corridor. There should be 2 small doors one towards store room

from sutures dressings etc are taken & one from scrub room into the OT. Temperature

should range from 19 C to 22 C with humidity of 45-55%. Adequate no. of power

plugs should be there.

Operating table should be regularly checked for smooth raising & lowering of table &

for tilting of table for trenderlenburg position & lateral tilt position. OT lights should

also be adjustable easily with removable handles so that it can be sterilized and

handled by OT personels. Tubings and devices should be covered with the disposable

sheets which can be removed easily after use. OTs should be spacious enough so that

troleys and staff can move around table easily.

Sterilisation in Operation Theaters

Fumigation of Operation Theater

The O T is disinfected by fumigation .

Fumigation can be achieved by fumigators as well as potassium

permanganate reaction technique.

Fumigation is done with the instrument STERITRAX

Fumigation chemical used is 40% FORMALIN.

Fumigator is set for 30 mins with timer adjustments in the instruments

The Scrub Room:-

It should have 2 doors one from corridor & one to OT.

Sinks with taps & soap holders that can be manipulated with elbows

should be present.

Sink design should be such that splashing on clothes is prevented.

Antislip floors easily cleaned shelves for gown packs & gloves should

be present.

Brushes for cleaning fingernails should be available.

Contents of Scrub Suite:-

A pair of pants/skirts/pyjamas & shirts;

A pair of masks , a head cap & a pair of gloves

A pair of O T shoes (conductive shoes are preffered to avoid any explosion

due to static charges which may induce fire in inflammable anesthetics

gases.

A surgical gown which are tied at its back by some non scrubbed staff so it

is non sterile at its back & below the waist . so one should keep his hands

above waist when not operating.

Draping the Patient/ Preparation of Surgical Site:-

Hair in the area of surgery are shaved off just before the scrubbing of the skin. The

time interval between the shave and skin preparation should be decreased. A

lubricating ointment is applied to eyes & they are covered with sterile towel. The

external auditory meatus is plugged and blocked if bleeding is anticipated. The

scrubbing should begin at the centre of surgical site & moved outwards

concentrically away from the site of operation to avoid the contamination of already

scrubbed site.

During intra oral procedures the mouth is rinsed with chlorhexidine mouth wash to

reduce the bacterial count in oral cavity. The iodophor compounds are effective for

skin preparation. Patient`s hair are covered with sterile head cover . Another towel

should cover chest and shoulders. Patient should be draped with sterile towels to

isolate the area of surgery & the suction tube is clipped to this towel so as to prevent it

from falling down. The site of needle puncture is made dry & 0.5 % chlorhexidine is

applied at that site. While operating the operating person can touch only the sterilized

drappings & sterile instruments handed over by assisting staff.

CONCLUSION

Dental environment is associoated with significant risk of bacterias, virus. So it is

very important maintain asepsis.To create a healthy environment instruments, hand

hygiene,protective clothing sterilization is important special care should be required

to maintain aseptic environment it includes proper disposal of blood,saliva containing

objects sharp instruments should be properly handled asepsis should be maintained by

the dentist for the prevention of patient and dentist itself.

REFERENCE

Textbook of Microbiology for dental students(3rd edition) by D.R.Arora and

Brij Bala Arora.

Textbook of Microbiology - 7th edition (ananthnarayan and paniker).

Dr.Neelima Anil Malik: Textbook of Oral & Maxillofacial Surgery, 1st

Edition.

Satish Chandra, Shaleen Chandra, Girish Chandra : text book of Operative

Dentistry, 1st Edition.

Ramya Raghu, Raghu Srinivasan : Clinical Operative Dentistry- Principles &

Practice, 1st Edition.

Monheims Local anesthesia and pain control in dental practice by C.Richard

Bennet(seventh edition).