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1. 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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2. 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. 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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4. 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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5. 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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6. 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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7. 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
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8. - Herpes
- 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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9. 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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10. 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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11. 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
11

12. 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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13. 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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14. 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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15. 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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16. 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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17. 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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18. 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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19. 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.
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20. 3. Glutaraldehydes as disinfectants :
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.
20

21. - Because iodine is insoluble in water, it has been routinely prepared as a
tincture by dissolving an iodide salt in alcohol.
- 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.
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22. - The intense penetration capability of phenols is the major factor associated
with their antimicrobial activity.
- 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
22

23. 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.
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.
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24. 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
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 3.5µm
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.
24

25. - Fit comfortably.
- Not leak out air
- 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
25

26. enamel, amalgam, gold and pumice can be flung and propelled from the oral
cavity.
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.
26

27. f. Hexitidine from pyrimidines.
g. Benzethonium chloride from quaternary ammonium group.
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.
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28. Waste disposal :
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.
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29. Hepatitis B :
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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30. 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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