Infection control

Introduction

Dental professionals are at an increased risk of cross contamination

while treating patients. They are exposed to a wide variety of microorganisms

in blood and saliva of the patients. These microorganisms can cause infectious

diseases. The discovery of the importance of asepsis in the prevention of

infection may be the single most important advance in the history of surgery.

Historic review:

- Antony Van Leewen Hook first observed tiny living particles what he

called “Animalcule” in 1667.

- In the 1800’s researches such as Louis Pasteur, Robert Koch, Igniz

Semmelweiss, Oliver wendell Holmis, Lord Joseph Lister established the

relation between the disease and the microorganisms. At that time there was

a lot of opposition for infection control method.

- Lord Joseph Lister studied the prevention of wound infection made between

1865 and 1891. His principles of asepsis were accepted.

- Further developments in Listerian asepsis occurred rapidly in the 1890’s

with the advent of steam sterilization, surgical masks, sterile gloves, sterile

gowns, sterile drapes and sterile sponges for the surgical wound.

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Route of transmission of microorganisms in the dental field

1. Patient to dental team :

This may occur by direct contact with patient’s saliva or blood, which

may lead to microbes entering through a cut in the skin.

Sprays or aerosols from the patients mouth may lead to droplet infection

through inhalation, mucosal surface of the eyes or cut in the skin.

Indirect contact involves transfer of microorganisms from the source i.e.

patients mouth to instruments or surface and subsequent contact with the

contaminated instrument or surface. Example cuts or puncture of the skin with

contaminated sharp instruments like needles, scalpel blades, burs, files, wires

etc.

2. Dental team to patient:

This mode of transmission is rare but could occur if proper procedures

are not followed.

If the hands of the dental team contains lesions or the hand are injured

while in patients mouth, blood borne pathogens could be transferred by direct

contact with patients mouth may gain entry through mucous membrane or open

tissues. Droplet infection to the patient from the dental team may also occur.

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3. Patient to patient:

Disease agents may be transferred from patient to patient by indirect

contact through improperly sterilized instruments, hand piece attachments,

operatory surface and hands.

4. Dental office to the community:

This pathway may occur if contaminated items are transported away

from the office. Eg. Contaminated impressions can infect dental laboratory

technicians who handle them. Infection can also occur when contaminated

waste is not disposed off properly.

The Development of infectious Disease

An infectious disease occurs when microorganisms in the body multiply

and cause damage to the tissues.

The infectious disease could be endogenous or exogenous in origin.

Caries, periodontal disease, cervico facial actinomycosis are some

examples of endogenous disease that are caused by the organisms normally

present in the oral flora. They cause disease only when given an opportunity to

enter deeper tissues of the body.

Exogenous diseases are caused by the microorganisms that are not

normally present in the body, but contaminate the body from outside. Example

Streptococcal throat infection, Hepatitis, AIDS etc.

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Stages in the development of an infectious disease

1. Incubation period

2. Prodromal stage

3. Acute stage

4. Convalescent stage

Incubation stage:

This stage is the period from the initial entry of the infectious agent into

the body to the time when the first symptoms of the disease appear.

Prodromal stage:

Prodromal means “receiving before” and this stage of a disease involves

appearance of early symptoms. The microorganisms would have multiplied to

numbers large enough to cause the first symptoms.

Acute stage:

Acute stage is when the symptoms of the disease are maximal and the

person is ill.

Convalescent stage:

This is the recovery stage. The number of microorganisms may decline

or the harmful microbial products are being rapidly destroyed by the body’s

defense system.

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Body’s Natural defense against infectious disease:

Body’s natural defense system is the nature’s gift to mankind. Before

man takes up any formulated steps to control the infectious disease body gets

into action to control or hault the spread of disease by its own defense line up.

These are.

a. Physical defence

b. Chemical defence

c. Inflammation

d. Immunity

Physical defense:

The body’s first line of defense against microbial attack is the skin and

the mucous membrane lining the respiratory tract, gastro intestinal tract and the

conjunctiva that covers the eyes. Any cut in the skin or mucous membrane can

result in the entry of micro organisms into the body.

Chemical defense:

Saliva, tears, sweat contain certain substances that can destroy bacteria.

Stomach contains a high concentration of HCl acid, which destroy many

bacteria.

Inflammation:

When the microbes do enter the body breaking the physical or chemical

barrier the first reaction of the body is inflammation of the area with its four

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characteristic signs of pain, swelling, redness and heat. The body attempts to

limit the area of attack. Phagocytes are sent to the area to ingest the microbes.

Immunity:

Immunity is the ability of the body to recognize, reject and destroy any

substance or organism that is not part of its original self.

Any substance that triggers the body’s immune system is called an

Antigen. The presence of an antigen in the body triggers the immune system to

produce what is called an antibody to counteract it. Antibody produced is

specific to a particular antigen. Immunity conveyed by an antibody is called

Humoral immunity.

Another type of immunity is the cell-mediated immunity. This mostly

involves the T- lymphocytes. The lymphocytes produce chemicals called the

“Lymphokines” that can destroy the microbes invading the body.

Inspite of all the built in defenses we often need additional help. The

most satisfactory way to achieve this is to vaccinate and let the body build up

its own immunity.

Antibiotics, antiviral drugs and antifungal drugs are available to stop the

activity of the microbes by bacteriostatic or bactericidal action.

Objectives of infection control

1. Decrease the number of pathogenic microbes to the level where normal

body resistance mechanisms can prevent infection.

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2. Break the cycle of infection from dentist, assistant and patient and eliminate

cross-contamination.

3. Treat all patients and instruments as though they could transmit an

infectious disease.

4. Protect patients and personnel from infection.

Terminology

Sterilization: The process that destroys all types and forms of microorganisms

including viruses, bacteria, fungi and bacterial endospores.

Disinfection: A less lethal process than sterilization it eliminates virtually all

pathogenic vegetative microorganisms, but not necessarily all microbial forms

(spores). Disinfection is usually reserved for large surfaces that cannot be

sterilized. Disinfection locks the margin of safety afforded by sterilization

procedures.

Transmissible Disease of Concern to Dentists:

- Hepatitis (Types A, B, non A / non B)

- HIV

- Syphilis

- Gonorrhea

- Influenza

- Acute pharyngilis

- Pneumonias

- Tuberculosis

- Herpes

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- Chickenpox

- Infectious mononucleosis

- Rubella

- Rubeola

- Mumps

Classification of instrument sterilization:

The categorization of instruments depends on the contact with different

tissue types to determine whether sterilization or disinfection is required. The

categories are as follows.

1. Critical items: Instruments that touch sterile areas of the body or enter the

vascular system and those that penetrate the oral mucosa. Examples are

scalpels, curettes, burs and files. Because of their potential for harboring

microorganisms, dental hand pieces also must be sterilized.

2. Semicritical items: Instruments that touch mucous membranes but do not

penetrate tissues. This includes amalgam condensers and saliva ejectors.

These items should be sterilized, if this is not possible high level

disinfection is required.

3. Non critical items: Those items that do not come in contact with oral

mucosa but are touched by saliva or blood contaminated hands while

treating patients. Such items include light switches working area. These

areas should be properly disinfected.

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Methods of sterilization

The four methods of sterilization that are generally accepted in dentistry

include steam under pressure, chemical vapor, dry heat sterilization and

glutaraldehyde solutions.

Steam under pressure – autoclaving

Steam sterilization has been a standard method of killing

microorganisms in dentistry for many years.

A temperature of 121°C, a pressure of 15lb is used for 15 to 20 minutes.

Denaturation and Coagulation of microbial protein occurs during exposure to

high temperature of steam under pressure. Advances in this method called

“flash” sterilization technique uses shorter time with higher temperatures.

There is however greater chances for sterilization errors to occur in this

technique.

Advantages:

- Short efficient cycle time.

- Excellent penetration facilitating exposure of all instrument surfaces to the

steam.

- Can sterilize water based liquids.

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Disadvantages:

- Rusting, corroding and dulling of instruments especially carbon steel

instruments.

- Instruments removed from the chamber are wet.

- Certain plastics and rubber are sensitive to heat and moisture and cannot be

placed in the autoclave.

Closed containers should not be used as they prevent passage of steam

to the container contents.

Dry heat sterilization

They use hot air to kill microorganisms. The technique requires a

temperature of 160°C for 2 hours. During the loading process instruments must

be separated to prevent the creation of air pockets leading to ineffective

sterilization. Recently a rapid heat transfer sterilizer was introduced operated at

190°C it will by rapid airflow sterilize unpacked instruments in 6mins and

packaged instruments in 12 minutes.

Advantages:

1. Effective and safe for sterilization of metal instruments and mirrors.

2. Does not cause rusting or corroding of instruments.

3. Does not dull cutting edges.

Disadvantages

1. Long sterilization time.

2. Poor penetration

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3. May discolour or char fabric.

4. Destroys heat labile dims

5. Unsuitable for hand pieces

Chemical vapour sterilization

This method is based on the factors of heat, water and chemical

synergism. The chemicals include alcohol, acetone, ketones and

formaldehydes. The water content is below the 15% level, above which rust,

corrosion and dullness of metal occur. The temperature requirements are 132°C

for 20 minutes. The composition of heat and chemicals is much kinder to metal

surfaces than the other techniques.

Advantages

- Has a short cycle time.

- Does not rust or corrode metal instruments including carbon steel.

- Does not dull cutting edges.

Disadvantages

- Instruments must be completely dried before processing.

- Chemical odour is released when the chemicals are heated.

Glutaraldehyde as immersion chemical steriliant :

For endodontic instruments sterilization by heat is the method of choice,

however the use of glutaraldehyde preparations for the chemical sterilization of

heat sensitive equipment has become a widespread practice.

Glutaraldehyde kills microorganisms by altering essential protein

components. The glutaraldehyde molecule has two active carbonyl groups

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which cross link with the microbial cell protein. Aqueous glutaraldehyde

solution is mildly acidic, but in this state it is not sporicidal. By the addition of

certain alkaline buffers it attains full antimicrobial activity. The shelf life of

such a glutaraldehyde solution is only 14 days.

Instruments contaminated with blood or saliva must remain submerged

in glutaraldehyde for 6 to 10 hours.

Advantages :

- Sterilizes heat sensitive instruments.

- Relatively non corrosive and not toxic.

Disadvantages :

- Requires long immersion time.

- Has an objectionable odour.

- Sterilization is non verifiable.

- Is irritating to mucous membranes.

Ethylene Oxide Gas (E.T.O.)

Ethylene oxide was first used as a sterilizing agent in the late 1940’s.

Since then ETO has become an increasingly popular means of sterilization

especially in hospitals. It has high penetration capacity. Temperature required

is low i.e. 25°C.

This makes it ideal for sterilizing heat sensitive instruments. Time

period required for proper sterilization varies from 10 to 16 hours.

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ETO sterilization seems an ideal solution for some dental instruments

such as hand pieces, it is best used in hospitals or other strictly controlled

environments. ETO is thought to be potentially mutagenic and carcinogenic.

Advantages :

- Operates effectively at low temperatures.

- Gas is extremely penetrative.

- Can be used to sterilize sensitive equipment such as dental handpieces.

- Sterilization is verifiable.

Disadvantages :

- Gas is potentially mutagenic and carcinogenic.

- Requires an aeration chamber.

- Cycle time lasts many hours.

Glass bead or hot salt sterilizers

Chairside sterilization of endodontic files, reamers and broaches can be

accomplished by using a glass bead or hot salt sterilizer. This device is a metal

crucible that heats a transfer medium of glass beads or salt. Clean endodontic

instruments of small mass are positioned in the transfer medium and allowed to

remain for a prescribed time. The transfer medium heats the endodontic

instrument through heat connection and kills any adherent microorganisms. At

a temperature of 220°C contaminated endodontic instruments require 15

seconds to be sterilized.

The glass beads used in the sterilizer should have a diameter of less than

1mm to be effective. Larger beads are not so effective in transferring heat to

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endodontic instruments because of large air spaces between the beads that

reduce the efficiency of the sterilizer.

The advantage of the hot salt sterilizer lies in the use of oridinary salt

which is readily available for replacement and eliminates the risk of clogging

which in common in glass bead sterilizer.

The salt is more porous and will not become fused under heat. Any salt

accidentally carried into the canal can easily be irrigated from the canals with

usual irrigating solution. The salt should be changed weekly or more depending

on the degree of humidity.

The hottest part of the sterilizer is the outer rim (periphery), starting at

the bottom layer. The temperature is lowest in the centre of the surface layer of

salt. To sterilize the instruments properly one should immerse it at least a

quarter inch below the salts surface and in the peripheral area of the sterilizer.

To sterilize disposable items such as needles, suture materials, scalpel

blades ionizing radiations such as gamma rays and U-V rays are commonly

used in industries.

Sterilization Monitoring

The goal of sterilization is the complete killing of all forms of microbial

life on the items been processed. An integral component of clinical sterilization

procedures is monitoring the efficiency of the system.

There are three methods from which sterilization monitoring can be done.

1. Biological monitoring.

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2. Chemical monitoring.

3. Physical monitoring.

Biological monitoring

Biological monitoring, the most meaningful way to verify sterilization,

involves the use of spore tests called biological indicators (BI’s).

BI’s contain highly resistant bacterial spores that are more difficult to

kill than any other microbe. Routine biomonitoring that demonstrates that the

sterilization procedure kills these spores provides the best guarantee of

successful sterilization.

BI’s are standard preparations of Bacillus stearothermophilus spores (for

steam or chemical vapour sterilization) or Bacillus subtilis spores (for dry heat

or ethylene oxide gas sterilization).

BI’s are packaged in different forms :

- Spores strips which are filter paper strips impregnated with the spores and

enclosed in an envelop through which the sterilizing agent penetrates.

- Spore Vials called self contained vials are vented to permit entry of the

sterilizing agent and contains a small paper strip or disk of spores, and a

small ampule of culture medium that is crushed and mixed with the spores

after processing through the sterilizer.

BI’s are placed in the sterilizing chamber inside the instrument packs.

They are processed through the sterilizer cycle, retrieved, incubated at

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appropriate temperature and examined for growth. Test BI’s that shows growth

indicates sterilization failure.

Chemical Monitoring :

This involves use of color – change or other indicators such as autoclave

tape, labels, special markings on bags, strips and packets on the outside and

inside of packs, bags or trays. External chemical indicators change colour after

brief exposure to high temperature. Internal chemical indicators are more

accurate and frequently test more than one parameter of the sterilizing process

(eg : temperature and time).

Physical monitoring :

It involves routine observation of the dials or groups indicating time,

temperature and pressure.

Handling sterile instruments

Post sterilization procedures involve drying, cooling, storage and

distribution. Handling of the sterile packages or trays must be kept at a

minimum to reduce chances of recontamination.

1. Drying : Wet packages after steam sterilization may indicate problems with

package composition, overloading of the chamber, improper arrangement of

the packs in the chamber, removal of the packages too soon after the

sterilization cycle or sterilizer malfunction. Sterilized packages that remain

or become wet may draw microorganisms through the packaging material

or compromise the integrity of the material itself.

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2. Cooling : Items being cooled after they are removed from the heat sterilizer

at the completion of the cycle must remain untouched and protected from

the environment. Blowing of non-sterile air over unwrapped instruments

will recontaminate them. Using a fan to cool down wrapped instruments is

acceptable.

3. Storage : Sterile packs and trays should be kept in dry, low dust, low traffic

areas away from sinks, and atleast a few inches away from floors, outside

walls and ceilings.

4. Distribution : Sterilized packs should be kept on disinfected trays for use at

chairside. The instruments should be handled aspectically with sterile tongs

and preferably placed on sterile on cleaned or disinfected tray.

Role of disinfectants in infection control

Operatory surfaces become coated with saliva, blood, exudate and other

debris. Such surfaces require cleaning and chemical disinfectants serve a very

useful purpose in infection control. However it is necessary to emphasize that

chemical sterilants and disinfectants should be used only when it is not

possible to sterilize or dispose of items that become contaminated during

treatment.

Infection control needs in dental treatment facilities require the use of

disinfectants in several forms :

1. Surface disinfectants.

2. Immersion disinfectants.

3. Hand antimicrobials.

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Surfaces disinfection is the treatment of environmental surfaces such as

cabinets, tables, chairs, units, light, x-ray unit etc.

Surface disinfection is accomplished by wiping the solution on the surface

and allowing it to remain moist and undisturbed for the manufacturers directed

time.

Immersion disinfection is the immersion of instruments, plastics and

other smaller items in a liquid disinfectant. Immersion disinfecting time will

vary by product but usually ranges from 5 to 30 minutes.

Hand antimicrobial treatment is the washing of hands with chemical

soap or lotion with resulting reduction in the number of hand microbes.

Classification of disinfectants

a. High level disinfectants

b. Intermediate disinfectants

c. Low level disinfectants

High level disinfectants have the ability to inactivate resistant bacterial

spores and all other microbial forms. Examples of high level chemical

disinfectants are ethylene oxide gas and immersion glutaraldehyde solutions

both of which are useful for sterilization of materials unable to withstand heat

sterilization procedures. Prolonged immersion times of 6 to 10 hours are

required to achieve sterilization with 2% and 3.2% preparations.

Intermediate level disinfectants may not inactivate bacterial spores

during routine usage, however intermediate level disinfectants do destroy other

forms of microbes particularly tubercle bacilli. Examples are formaldehydes,

chlorine compounds, iodophors, alcohols and phenolic compounds.

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Low level disinfectants provide the narrowest antimicrobial range and

include quaternary ammonium compounds, simple phenols and detergents.

Such chemicals are suitable for cleaning surfaces in a treatment area.

Categories of Chemical Disinfectants

1. Alcohols : Ethyl alcohol and isopropyl alcohol have been used in dentistry

for surface disinfection and as skin antiseptic.

They denature proteins and lipid solvents.

- Alcohols exhibit a fairly broad antimicrobial spectrum of activity.

- Alcohols are relatively ineffective in the presence of tissue proteins such as

those found in saliva and blood.

- They are used in concentration of 70%

2. Chlorine compounds :

The most commonly used chlorine containing compounds are

hypochlorite solutions and chlorine dioxide preparations.

- 0.5% sodium hypochlorite is effective in inactivating hepatitis B virus.

- (Sodium hypochlorite is unstable, and fresh solutions must be prepared).

- Disadvantages includes : metal corrosion, irritation to the skin and other

tissues and it destroys many fabric.

3. Glutaraldehydes as disinfectants :

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Belong to the category of high level disinfectants. In the concentrations

of 2% and 3.2% glutaraldehydes are effective against all vegetative bacteria

including M.tuberculosis, fungi and hepatitis B viruses. They are able to

destroy microbial spores in 6 to 10 hours.

Glutaraldehyde offers an alternative as immersion sterilants for items

that cannot withstand repeated heat.

- Their low surface tension permits them to penetrate blood or exudate to

reach instrument surface.

- Rubber and plastic items are not degraded during prolonged immersion in

glutaraldehyde.

- It can cause irritation of hands thus direct physical contact between

glutaraldehyde solutions and tissues should not occur.

- Repeated exposure to this chemical can induce hypersensitivity and other

dermatologic reactions.

4. Iodophores :

- Traditionally iodine has been used as an antiseptic for application onto skin,

mucous membranes, abrasions and other wounds.

- It is a potent germicidal and has high reactivity with its substrates.

- Because iodine is insoluble in water, it has been routinely prepared as a

tincture by dissolving an iodide salt in alcohol.

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- Draw backs with iodine are, it is irritating allergenic, corrodes metals, stains

skin and clothing.

- Hypersensitivity reactions to iodine are also reported.

- Attempts to use the powerful germicidal action of iodine while reducing its

caustic and staining effects have led to the synthesis of later generation

iodine compounds. These compounds called iodophors retain a similar

broad antimicrobial spectrum as iodine, in addition have certain advantages

over elemental iodine in infection control. The iodophors are less irritating

to tissues, significantly less allergenic, do not stain skin or clothing and

have a prolonged activity after application.

- Iodophors are prepared by combining iodine with a solubilizing agent or

carrier.

- Iodophor antiseptics are useful in preparation of the oral mucosa for local

anesthesia and surgical procedures.

5. Phenolic compounds :

- These agents act as cytoplasmic poisons by penetrating and disrupting

microbial cell walls, thereby leading to denaturation of intracellular

proteins.

- The intense penetration capability of phenols is the major factor associated

with their antimicrobial activity.

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- A new class of phenolic compounds called the complex synthetic phenols

contain more than one phenolic agent. These phenolics act synergistically to

afford a broad antimicrobial spectrum.

- The penetration properties of phenols tend to cause epithelial toxicity in

exposed tissues.

Personal barrier protection

OSHA (Occupational health and safely administration) have suggested

basic areas for personal barrier protection. They are :

1. Hand washing.

2. Gloves

3. Gowns

4. Masks

5. Protective eye wear

6. Rubber dam

7. Pre procedural mouth rinse.

Hand washing : Hands must always be washed at the start of each day before

gloving, after removal of gloves and after touching inanimate objects likely to

be contaminated by patients saliva or blood . Hand washing with plain soap and

water appears to be adequate for routine examination and non surgical

procedures. For surgical procedures an antimicrobial surgical hand scrub

should be used. Hand washing procedure begins with a thorough initial

scrubbing of all surfaces of the nails, fingers, hands and lower arms with an

antimicrobial preparation. Drying should be done with a clean paper towel.

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All gross subnail contaminations should be removed. The scrub begins

at the tip of one finger of one hand. The long axis of the finger is then divided

into 4 surfaces and 30 scrub strokes are applied to each surface. After this the

inter finger webbing is given 30 strokes. The length of the forearm is divided

onto thirds and each of the four surfaces is scrubbed toward the elbow. After

both arms are scrubbed the rinse should be done with elevated arms so that the

H2O will drain from the fingertips down the hands, arms and finally the elbows.

Gloves : Gloves are required in dentistry when the dentist has to come in

contact with potentially infectious secretions or for contact with oral mucous

membrane. Four types of gloves are identified for use in dentistry.

i. Sterile surgical gloves.

ii. Non sterile latex gloves.

iii. Vinyl examination gloves.

iv. Utility gloves.

Surgical gloves : Best fitting and generally the most expensive disposable

gloves is the sterile surgical glove. Used when maximum protection is

indicated. They are made of high quality latex.

Latex examination gloves : These are the most commonly used gloves in

dentistry. Available in a variety of sizes designated as S,M,L.

An occassional hyper sensitivity to latex has been reported. Inadequately

drying the hands before gloving has proven to cause dermatitis.

Vinyl examination gloves :Sometimes referred to as “Over gloves”. Used

when an intra oral procedure is necessarily interrupted for a brief time.

Following a washing and drying of the gloved hands, the over gloves can be

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slipped on over the regular examination gloves and removed when contact with

the patient resumes.

Heavy utility gloves : These are non disposable gloves. They should be worn

when handling contaminated instruments, when using chemical sterilants and

during general cleaning of the treatment area. These gloves can be washed,

sterilized, disinfected and reused and are puncture resistant.

Protective clothing gowns

Gowns, Aprons or lab coats must be worn when the skin or clothing is

likely to come in contact with saliva or blood. They should be changed when

visibly soiled. These garments should be limited to the dental office and not be

worn out side.

Masks :

Masks protect the face, oral mucosa and nasal mucosa of the dentist

from splatter of blood or saliva from the use of high speed hand piece with

water coolant.

It also protects both the dentist and the patients from aerosol

contamination by potential from the respiratory tract.

Effective face masks are to have a minimum filtration of 95% of 3.5m

particles and the ability to block aerosols as well as larger particles of blood,

saliva and oral debris. A good mask should have the following features.

- Fit comfortably.

- Not leak out air

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- Fit around the entire periphery of the face.

- Not irritate skin.

- Provide breathability.

- Not cause fogging of protective eyewear.

- Not have an objectionable odour.

- Not touch lips or nostrils.

Face masks should be changed once per hour or between each patient.

The mask should not be touched because wet masks significantly decrease the

filtration capacity.

They are available in a variety of materials like paper, cloth, foam, fibre

glass and other synthetic materials.

Protective eye wear

All dental personnel involved in treatment should wear protective eye

wear in the form of glasses to prevent trauma to the eye tissue from flying

droplets or aerosols.

The eyes due to limited vascularity and lower immense abilities are

susceptible to macroscopic and microscopic injury.

Protective eye wear should be available to patients as well as dental

personnel. The supine position renders the patient particularly vulnerable to

falling objects in the head and neck area. Ultrasonics and high speed hand piece

spray create potential pathogenic aerosols, droplets and spatters pieces of

enamel, amalgam, gold and pumice can be flung and propelled from the oral

cavity.

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All protective eyewear should be cleansed after every appointment.

Eyewear be washed with soap first, then rinsed with water and an appropriate

surface disinfectant can then be used.

Rubber dam :

The use of a rubber dam during certain dental procedures is advocated.

The role of the dam in barrier technique is emerging as yet another means of

controlling airborne contaminants.

Rubber dam isolation has been shown to significantly reduce infectious

particles in aerosols. Used in combination with a pre-operative rinse of

chlorhexidine gluconate the risk of contamination can be further reduced.

Pre procedural mouth rinse

The use of antimicrobial mouth rinse prior to any operative procedure

reduces the microorganisms that may escape a patients mouth during dental

care through aerosols, spatters or direct contact.

Examples of antiseptic mouth rinses are :

a. Chlorhexidine, Alexidine from Bis-geranide class.

b. Octenidine of Bis-pyridine class.

c. Iodine, iodophors from halogen group.

d. Peroxide, perborate of oxygenating agents.

e. Phenol, Thymol from phenolic compounds.

f. Hexitidine from pyrimidines.

g. Benzethonium chloride from quaternary ammonium group.

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Although the antiseptic mouth rinses are effective in reducing the oral

micro-organisms, they are bitter in taste and cause staining of teeth.

Infection control consideration in the field of restorative dentistry and

Endodontics

The primary goal of infection control is to reduce the risk of cross

contamination between patients and the dental professionals. The same general

principles of infection control are applicable in the field of restorative dentistry

and endodontics are discussed.

Note on waste management

Wastes could be infectious waste, contaminated waste, hazardous waste,

toxic waste or bio-medical waste.

Infectious waste is waste capable of causing an infectious disease.

Contaminated waste : Contains items that have had contact with blood or

other body secretions.

Hazardous waste contains waste posing a risk to humans or

environments.

Biomedical waste is any solid waste generated in the diagnosis,

treatment or immunization of human beings or animals.

Waste disposal :

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Blood in a liquid or semisolid from can be poured or evacuated into the

waste water system.

Pathologic waste like teeth and other waste tissues are considered to be

potentially infectious and thus their disposal should be regulated. The waste

should be disinfected and put in plastic bags.

Sharp items like needles should be placed in closed leak proof

containers for disposal.

Note on AIDS

Is caused by a lethal RNA virus called Human immunodeficiency virus

(HIV). Once HIV infects a host that person remains infected for rest of his life.

Most of those infected are asymptomatic and are unaware that they are HIV

positive. Regardless of the stage of disease all HIV infected persons are

potentially infections. The incubation period from the time of infection to the

development of signs and symptoms of AIDS is long around 11 years. Thus

many years are available for HIV infected individuals to spread the virus.

Fortunately AIDS virus is not a virulent virus. When careful personal

barrier techniques such as gloves, mouth mask, disinfection principles are

followed dentists, staff and patients should feel safe from contracting the

disease.

During surgical procedures using double gloves prevents perforation of

the inner gloves and therefore gives added protection.

Hepatitis B :

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It is a major cause of acute and chronic liver infection, cirrhosis and

primary hepatocellular carcinoma.

Mode of transmission in dentistry :

HBV is transmitted both percutaneously and non percutaneously.

Because dental treatment involved the used of small, sharp instruments

multiple opportunities exist for inadvertant percutaneous wound to the operator

and staff. Non percutaneous dental transmission includes the transfer of

infectious bodily secretions such as saliva, blood and crevicular fluid.

Prevention of transmission of HBV can be achieved by the use of proper

personal barrier protections. Hepatitis B vaccination is available and should be

mandatory taken by all clinicians.

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Summary and Conclusion

“Prevention is better than cure” – This saying holds true all the more in

the field of infection control. The goal of infection control is to provide optimal

protection for clinicians and patients from cross contamination in the dental

environment.

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