4. STERILIZATION
Sterilization is defined as the process where all the
living microorganisms, including bacterial spores
are killed.
Sterilization can be achieved by physical, chemical and
physiochemical means.
Disinfection is the process of elimination of most
pathogenic microorganisms (excluding bacterial
spores) on inanimate objects.
Sterilization is an absolute condition while disinfection is
not.
5. Sterilization (or sterilisation) is a term referring to any
process that eliminates (removes) or kills (deactivates)
all forms of life and other biological agents (such as
viruses which some do not consider to be alive but are
biological pathogens nonetheless), excluding prions
which cannot be killed, including transmissible agents
(such as fungi,bacteria, viruses, spore forms,unicellular
eukaryotic organisms such as plasmodium, etc.) present
in a specified region, such as a surface, a volume of
fluid, medication, or in a compound such as biological
culture media.
----Lakshya Rani et al /J. Pharm. Sci. & Res. Vol. 8(6),
2016, 558-564
6.
7. Instrument washers/thermal
disinfectors:
These devices may look like the instrument
washers.
The high temperature of the water and
chemical additives in these devices cleans and
disinfects the instruments.
8. Principles and procedures for handling and cleaning
instruments after treatment:The safest and most
efficient instrument cleaning procedures involve
ultrasonic cleaning of used instruments kept in a
perforated basket or cassette throughout the cleaning
procedure.Used instruments are commonly placed in an
anti microbial solution as this softens and loosens
debris.
Next, move the or basket of instruments into an
ultrasonic cleaning device, rinse them, and then
carefully inspect the instruments for debris.
Dip instruments likely to rust into a rust inhibitor solution.
Drain & dry instruments with absorbent towel
9. Ultrasonic cleaning devices:
An ultrasonic cleaner uses sound waves, that
are outside the human hearing range to form
oscillating bubbles, a process called cavitation.
These bubbles act on debris to remove it from
the instruments.
10. In general, the timer is activated for three to six
minutes for loose instruments and ten to
twenty minutes for instrument cassettes, and
the timing is adjusted as necessary.
11. Use of a system utilizing locked cassettes eliminates the
need to sort, handle and hand scrub individual
instruments - reducing the risk of infection from
contaminated instruments - and results in savings of, on
average, five minutes during instrument reprocessing,
as well as fewer damaged instruments, since the
instruments are locked in position during reprocessing
12. Sterilization:
Parameters such as time, pressure and
temperature vary according to the type of
sterilizer, materials being sterilized and individual
models within sterilizer brands.
The first step in determining the settings for the
sterilizer is to refer to the manufacturer’s
instructions. Sterilizers are medical devices,
requiring clearance by the Food and Drug
Administration before manufacturers may offer
them for sale.
The FDA requires rigorous testing to ensure an
adequate margin of safety in each cycle type
described in the instructions
13. CRITERIA DECIDING TEMPERATURE OF STERLIZATION
Microorganisms thrive at a wide range of temperatures; they have
colonized different natural environments and have adapted to extreme
temperatures. Both extreme cold and hot temperatures require
evolutionary adjustments to macromolecules and biological processes.
Psychrophiles grow best in the temperature range of 0–15 °C whereas
psychrotrophs thrive between 4°C and 25 °C.
Mesophiles grow best at moderate temperatures in the range of 20 °C to
about 45 °C. Pathogens are usually mesophiles.
Thermophiles and hyperthemophiles are adapted to life at temperatures
above 50 °C.
14. HOT AIR OVEN
A holding period of 160oC( 320oF) for 1 hr is used to
sterilize glassware, swabs, liquid paraffin, dusting
powder, fats and grease. It is suitable for dry powders
and water free oily substances.
Since hot air is a bad conductor of heat its penetrating
power is low.
It must be fitted with a fan to ensure even distribution of
air and elimination of air pockets.
The material should be arranged so as to allow free
circulation of air in between the objects.
15. The oven must be allowed to cool slowly for about 2hrs before the door is ope
since the glassware may crack due to sudden or uneven cooling.
16. ADVANTAGES
Effective and safe sterilization of metal instruments
and mirrors.
No corrosion of Carbon steel instruments and
burs.
DISADVANTAGES
Long cycles.
Poor penetration.
Uneven heating.
Damage to heat sensitive items.
17. GLASS BEAD AND HOT SALT STERILISER
The glass bead steriliser uses a metal cup
with glass beads of 1 mm diameter in it.
The hot salt container uses ordinary table salt.
The temperature range for both varies from
425oF To 475oF
18. MOIST HEAT
Moist heat kills microorganisms by denaturing proteins.
Denaturation involves changes in the chemical or
physical properties of proteins. It includes structural
alterations due to destruction of the chemical bonds
holding proteins in a three dimensional form.
As proteins revert to a two dimensional form they
coagulate & become nonfunctional.
19. Temperatures below 1000C
Pasteurization
Its purpose is to reduce the bacterial population of
a liquid such as milk and destroy organisms that
may cause spoilage
Spores are not affected by this method
20. Temperatures at 1000C (boiling)
Vegetative bacteria are killed almost immediately at 90-1000C,
but sporing bacteria require prolonged periods of boiling.
It is considered as a method for disinfection.
A minimum exposure period of 30min. is recommended to
kill vegetative bacteria.
Sodium bicarbonate 2% conc. is added to increase
the efficiency of process.
21. Advantages
Rapidity, economic , no elaborate equipment,
good penetration and harmless to wide range of
dental materials.
Diasadvantages
Dulls The Cutting Edges
Can Also Cause Corrosion
22. STEAM UNDER PRESSURE
Moist heat in the form of pressurized steam is regarded
as the most dependable method for destruction of all
forms of bacterial life including spores.
This method is incorporated into a device called the
AUTOCLAVE.
Over a hundred years ago, French ,German
microbiologists developed the autoclave.
23. As the water molecules in steam become more
energized, their penetration also increases
Same principle is used in home pressure cooker.
Pressure in autoclave –15lbs/sq. inch
Temperature121.50C
Time - 3 to 30 min
After the sterilization cycle, the sterilizer must
depressurize and the packs remain in the sterilizer for
drying.
The drying phase may take anywhere from 20-45
minutes. The unit must only be opened after completion
of the drying cycle.
24. • This method can be used for a broad variety of items such as
instruments, clothing, glassware and intravenous solutions etc.
•Limitations:
• Plastic ware melts in high heat
• Sharp instruments become dull ( corrosion )
• Many chemicals breakdown during the sterilization process,
and oily substances cannot be treated since they do not mix
with water.
• A new form of autoclave called the Prevacuum autoclave
has been developed, which draws air out of the chamber at
the beginning of the cycle. The major advantage of this is
minimal exposure.
25. NON IONISING RADIATION
UV RADIATION
The wavelength of UV radiation ranges from 328 nm to
210 nm .
Its maximum bactericidal effect occurs at 240–280 nm.
Inactivation of microorganisms results from destruction
of nucleic acid through induction of thymine dimers.
26. IONIZING RADIATION
X-raysand gamma rays have wave length shorter
than UV light.
As these rays can pass through microbial molecules,
they force electrons out of their shells, thereby causing
ionisation.
The ions quickly combine with & destroy proteins and
nucleic acid such as DNA, causing death.
Can be used for syringe sterilization.
27. FILTRATION:
Filtration does not kill microbes, it separates
them out. Membrane filters with pore sizes
between 0.2-0.45 μm are commonly used to
remove particles from solutions that can't be
autoclaved.
28. Earthenware filters:
Asbestos filters:
Sintered glass filters: These are made from
finely ground glass that are fused
sufficiently to make small.
particles adhere to each other. They are
usually available in the form of disc fused into
a glass funnel.
29. SONIC AND ULTRASONIC
VIBRATIONS:
Sonic and ultrasonic vibrations: sound waves of
frequency >20,000 cycle/second kills bacteria and some
viruses on exposing for one hour. High frequency sound
waves disrupt cells.
They are used to clean and disinfect instruments as well
as to reduce microbial load.
30. STERILITY ASSURANCE:
All the efforts that go into the preparation of instruments are
futile if the sterilization process itself is not successful.
There is no way of seeing that instruments are sterile by
simply observing the sterilizers and packs, even though a
chemical or mechanical indicator may have changed.
An indicator such as autoclave tape may change colour
when exposed to heat, but there is a possibility that the heat
was not present for the proper length of time or that there
was inadequate pressure.
Indicators that go on the outside of the packs are useful for
identifying processed and unprocessed packs. Failure of
sterilization can occur due to mechanical malfunction of the
sterilizer or due to operator error. There are several methods
to provide assurance of sterility
31. Chemical indicators:
Chemical indicators indicate the presence of
certain conditions during the sterilization cycle,
such as the presence of heat and steam.
32. Class 1 - Process Indicators: These are placed on the
outside of packs and are useful in determining which packs
have been properly processed versus those that have not.
Class 1 process indicators include autoclave tape and the
colour change indicators embedded on the outside of
sterilization packaging materials.
Class 2 - Bowie-Dick Indicators: These show the pass/fail
in pre vacuum sterilizers. This test is conducted daily with the
chamber empty, (10) during the first cycle of the sterilizer, and
is available as a kit from commercial sterilization monitoring
companies.
Class 3 - Temperature-Specific Indicator: These react to
one of the critical parameters of sterilization and indicate
exposure to a specific value such as temperature or psi.
33. Class 4 - Multi-parameter Indicators: These react to
two or more of the critical parameters in the same
manner as Class 3 indicators.
Class 5 - Integrating indicators: These are designed
to react to all critical parameters of sterilization cycles.
36. Biological monitoring:
The use of biological monitors (spore tests) is the
most reliable method to validate that the sterilizer
is functioning and that the sterilization of
instruments is effective .
These monitors consist of paper strips or vials
impregnated with bacterial spores that are
specifically resistant to the sterilization process.
New spore tests have been developed that
enable completion of biological monitoring in-
office and yield results in as little as 24 hours.
37. According to the Centers for Disease Control, dental instruments are
classified into three categories depending on the risk of transmitting
infection
Critical
instruments
steam under pressure
(autoclaving), dry
heat, or heat/chemical
vapour
forceps, scalpels,
bone chisels, scalers
and surgical burs
Semi-critical
instruments
Sterilization is not
feasible and,
therefore, high-level
disinfection is
appropriate
contact mucous
membranes or non
intact skin, such as
mirrors, reusable
impression trays and
amalgam condensers
Non-critical
instruments
be reprocessed
between patients by
intermediate-level or
low-level
disinfectionbe
contact only with
intact skin such as
external components
of x-ray heads, blood
pressure cuffs and
pulse oximeters.
38. Some instruments and materials are single-use only.
Single use items should be segregated in the operatory,
and those that are sharp or otherwise pose a risk of
injury must be discarded into a sharps container Items
without risk, such as a saliva ejector, can be thrown into
the trash.
39. Cleaning and disinfection strategies for blood
spills
Strategies for decontaminating spills of blood
and other body fluids differ by setting and
volume of the spill.
The person assigned to clean the spill should
wear gloves and other PPE as needed.
40. Visible organic material should be removed with
absorbent material Nonporous surfaces should be
cleaned and then decontaminated with either an
hospital disinfectant effective against HBV and
HIV or an disinfectant with tuberculocidal claim
(i.e., intermediate-level disinfectant).
However, if such products are unavailable, a
1:100 dilution of sodium hypochlorite (e.g.,
approximately ¼ cup of 5.25% household chlorine
bleach to 1 gallon of water) is an inexpensive and
effective disinfecting agent.
41. The Centers for Disease Control and Prevention (CDC)
states that,“Contaminated instruments should be
handled carefully to prevent exposure to sharp
instruments that can cause percutaneous injury.’’
The Occupational Safety and Health Administration
(OSHA) says, “The person handling the instruments
through removal, cleaning, packaging and sterilization
needs to use heavy-duty gloves to help prevent injury
with sharp contaminated instruments.”
42. Instrument washers:
Instrument washers use high-velocity hot
water and a detergent to clean instruments
Instrument washers for dental offices come in
two different designs.
One is a counter-top model,
kitchen dishwasher
Some models have the ability to dry the
instruments after washing, some do not
43. Packaging:
Packaging used for instruments and cassettes
prior to sterilization includes wrap, paper pouches,
plastic pouches, combination paper/plastic
pouches and nylon tubing.
Sterilization packaging is specifically designed to
allow penetration of heat, steam or vapour and
then to seal the sterilized instruments inside the
package for sterile storage .
After sterilization, instruments should remain in
packages until use.
44. disinfectants:
An ideal antiseptic or disinfectant should have
following properties:
Should have wide spectrum of activity
Should be able to destroy microbes within
practical period of time
Should be active in the presence of organic
matter
Should make effective contact and be
wettable
Should be active in any pH
Should be stable
45. Should have long shelf life
Should be speedy
Should have high penetrating power
Should be non-toxic, non-allergenic, non-irritative
or non-corrosive
Should not have bad odour
Should not leave non-volatile residue or stain
Efficacy should not be lost on reasonable dilution
Should not be expensive and must be available
easily Such an ideal disinfectant is not yet
available.
46. Classification of disinfectants:
1. Based on consistency
a. Liquid (E.g., Alcohols, Phenols)
b. Gaseous (Formaldehyde vapor, Ethylene oxide)
2. Based on spectrum of activity
a. High level
b. Intermediate level
c. Low level
3. Based on mechanism of action
a. Action on membrane (E.g., Alcohol, detergent)
b. Denaturation of cellular proteins (E.g., Alcohol, Pheno
c. Oxidation of essential sulphydryl groups of enzymes (E.g., H2O2, Halogens)
d. Alkylation of amino-, carboxyl- and hydroxyl group (E.g., Ethylene Oxide,
Formaldehyde)
e. Damage to nucleic acids (Ethylene Oxide, Formaldehyde)
47. Infection control in dentistry requires the use of
disinfectants in several forms
1.Surface disinfectants
2.Immersion disinfectants
3.Hand antimicrobials
48. Surface disinfection is the treatment of
envioronmental surfaces such as cabinets, chairs,
lights, x-rays and similar surfaces where the items are
too large or sensitive to be immersed in disinfecting
chemicals. It is accomplished by spraying or wiping the
solution on the surface.
Immersion disinfection also called cold sterilisation is
the immersion of instruments, plastics, in a liquid
disinfectant. Time is usually 5 to 30 minutes
49. Immersion sterilization is the use of an agent that
has the capability of killing all living microorganisms
and infective agents in 6 to 10 hours. The items
should be completely immersed in the solution
Hand antimicrobial treatment it is the specific
art of washing or otherwise treating hands with a
chemical soap or lotion with resulting reduction in
the number of hand microbes
50. The tuberculocidal claim is used as a
benchmark to measure germicidal potency.
Germicides labeled as "hospital disinfectant"
without a tuberculocidal claim pass potency
tests for activity against three representative
microorganisms: Pseudomonas aeruginosa,
Staphylococcus aureus, and Salmonella
choleraesuis
51. LEVELS OF DISINFECTION
1.High level disinfection – these disinfectants
must inactivate resistant bacterial spores and all
other microbial forms
E.g. ethylene oxide gas, immersion
gluteraldehyde solutions
2. Intermediate level disinfection– these disinfectants
do not inactivate spores during routine use but they
destroy other forms of microbes
E.g. formaldehyde, chlorine compounds,
iodophors, alcohols, phenolic compounds
52. 3.Lowlevel disinfectants - provide the
narrowest antimicrobial range
E.g. quaternary ammonium compounds, simple
phenols and detergents. Such compounds are
suitable for cleaning environmental surfaces
53. ALCOHOLS:
Mode of action: Alcohols dehydrate cells, disrupt
membranes and cause coagulation of protein.
Examples: Ethyl alcohol, isopropyl alcohol and methyl
alcohol
Application-It can be used to disinfect surfaces. It is
used to disinfect clinical thermometers. Methyl alcohol
kills fungal spores.
Disadvantages: Skin irritant, volatile (evaporates
rapidly), inflammable.
54. ALDEHYDES
GLUTERALDEHYDE
2% solution is effective. It destroys
vegetative cells within 10 min to 30min
and spores in 10 hrs.
Itis recommended for use on surgical
instruments where residual blood may be
present.
It can be used to sterilize optical equipment
such as the optic fiber endoscopes.
55. DISADVANTAGE
It can damage many metal items.
E.g. nickel coated impression trays & carbon steel
burs will often discolour and corrode, respectively
when immersed in gluteraldehyde solution for
prolonged periods
It can cause hypersensitivity on repeated
exposure so instruments immersed in
gluteraldehyde should be thoroughly rinsed in
sterile water prior to use
56. FORMALDEHYDE
It is gas at high temperatures & solid at room
temperature.
In aqueous solutions, it is bactericidal, sporicidal
and virucidal.
When 37 gms. of the solid are suspended in
100ml of water a solution called formalin results.
Formalin is utilized for inactivating virus in vaccines
& producing toxoids from toxins.
10% Formalin containing 0.5% sodium tetraborate is
used to sterilize clean metal instruments.
57. FUMIGATION
Electric Boiler Fumigation Method:
For Each 1000 cu.ft of the volume of the operation
theatre 500ml of formaldehyde (40% solution)
added in 1000ml of water in an electric boiler.
Switch on the boiler, leave the room and seal the
door. After 45 minutes (variable depending to
volume present in the boils apparatus) switch off the
boiler without entering in to the room .
58. Potassium Permanganate Method: For every 1000 cubic
feet add 450gm of Potassium permanganate (KMnO4) to 500
ml of formaldehyde (40% solution). Take about 5 to 8 bowels
(heat resistant; place it in various locations) with equally
divided parts of formaldehyde and add equally divided
KMnO4 to each bowel. This will cause auto boiling and
generate fume.
Neutralize Residual formalin gas with Ammonia by exposing
250 ml of Ammonia per liter of Formaldehyde used.
Place the ammonia solution in the centre of the room and
leave it for 3 hours to neutralize the formalin vapour
59. ETHYLENE OXIDE (EO):
Mode of action: It is an alkylating agent. It acts by
alkylating sulfydryl-, amino-, carboxyl- and hydroxyl-
groups.
Properties: It is a cyclic molecule, which is a colorless
liquid at room temperature. It has a sweet ethereal
odor,
readily polymerizes and is flammable.
Application: It is a highly effective chemisterilant,
capable of killing spores rapidly. Since it is highly
flammable, it is
usually combined with CO2 (10% CO2+ 90% EO) or
dichlorodifluoromethane. It requires presence of
humidity. It has
60. good penetration and is well absorbed by
porous material. It is used to sterilize heat
labile articles such as bedding,
textiles, rubber, plastics, syringes, disposable
petri dishes, complex apparatus like heart-lung
machine, respiratory and dental equipments.
Efficiency testing is done using Bacillus subtilis
var niger.
Disadvantages: It is highly toxic, irritating to
eyes, skin, highly flammable, mutagenic and
carcinogenic.
61. HALOGEN
These are a group of highly reactive elements whose
atoms have 7 electrons in the outer shell.
Two halogens chlorine & iodine are commonly used for
disinfection.
62. CHLORINE
Available as gas
organic compound
inorganic compounds
Most commonly used as hypochlorites
The disinfectant action results from it’s ability to
liberate free chlorine.
In aqueous solutions the liberated Cl ions
reacts with water to form hypochlorous acid.
63. DAKIN’s solution
0.5% sodium hypochlorite
Extensively for wounds during the I & II World
War
It is used to treat athlete’s foot.
64. Chloramines
Chloramines-T are organic compounds
Chlorine and amino groups.
Compounds release free chlorine more
slowly than hypochlorite solutions
More stable.
Used for general wound antisepsis and root canal
therapy
65. IODINE
Iodine is more reactive and more germicidal.
Iodine acts on the tyrosine portions of protein
molecules.
Tincture of iodine 2% iodine solution in ethyl alcohol
used as an antiseptic for application over skin and
mucous membrane
DISAD VANTAGES
Irritating
Allergic
Corrodes metal
Stains skin and clothes
66. Clinical sterilization:
Infection control:
• Microorganisms are ubiquitous.
• Since pathogenic microorganisms cause
contamination, infection and decay, it becomes
necessary to remove or destroy them from
materials
and areas.
67. Preprocedural mouth rinse:
Phenolic related essential oils; Bis-biguanides;
Quaternary ammonium compounds; Halogens;
Oxygenating agent; A commercial mouthrinse containing
0.05 percent CPC when used as a preprocedural
mouthrinse was equally effective as CHX in reducing the
levels of spatter bacteria generated during ultrasonic
scaling.
68. Hand sterilization:
For routine dental examination procedures, hand washing is
achieved by using either a plain or antimicrobial soap and water.
The purpose of surgical hand antisepsis is to eliminate transient
flora and reduce resident flora to prevent introduction of organisms
in the operative wound, if gloves become punctured or torn.
At the beginning of a routine treatment period, watches and jewelry
must be removed and hands must be washed with a suitable
cleanser
69. Personal barrier protection:
• Personal protective equipment (PPE), or barrier
precautions, are a major component of Standard
precautions.
• PPE is essential to protect the skin and the mucous
membranes of personnel from exposure to infectious or
potentially infectious materials.
• The various barriers are gloves, masks, protective eye
wear, surgical head cap & overgarments.
70. eye wear
causes of eye damage:
1. Aerosols and spatter may transmit infection
2. Sharp debris projected from mouth while
using air turbine handpiece, ultrasonic scaler
may cause eye injury.
3. Injuries to eyes of patients caused by sharp
instruments especially in supine position
71. PERIODONTIC INSTRUMENT
Ultrasonic scalars:
Soak inserts in a container containing 70% isopropyl
alcohol for removal of organic debris; Rinse cleaned
inserts thoroughly in warm water to remove all
chemicals.
As a final rinse, replace the insert into the scaler
handpiece and operate the scaler for 10 seconds at the
maximum water flow setting to flush out any retained
chemicals; Dry completely with air syringe; Package in
proper wrap, bags, pouches, trays, or cassettes; Add
spore tests and chemical indicators;
Ethylene Oxide is the preferred method of choice;
Dry heat and chemical vapor methods of sterilization are
72. Handpiece asepsis:
Oral fluid contamination problems of rotary equipment
and especially the high-speed hand piece involve:
contamination of hand-piece external surfaces and
crevices; turbine chamber contamination that enters the
mouth; water spray retraction and aspiration of oral
fluids into the water lines of older dental units; growth of
environmental aquatic bacteria in water lines; exposure
of personnel to spatter and aerosols generated by
intraoral use of rotary equipment
73. Better infection-control measures than chemical treatment alone are
currently available for handpieces and their attachments to provide
a greater assurance that they do not contribute to the spread of
diseases. These measures include either autoclaving or dry heat
treatment in conjunction with cleaning and chemical disinfection.
Prasanth et al. (2010)[40] in their study showed that usage of
high vacuum suction simultaneously to using airotor
handpiece or ultrasonic scaler resulted in decrease in the
production of aerosols. They also stated that flushing 0.5%
sodium hypochlorite in the dental waterline tubings helps in
the reduction of biofilm formation.
74. A one-handed ‘scoop’ technique or a mechanical device designed
for holding the needle sheath curing recapping is the recommended
approach for recapping (all needles need to be recapped after use
or when replacing on the operative tray or prior to disposal).
Syringes and needles, scalpel blades, and other sharp items must
be placed in puncture-resistant containers for later disposal (there
are several companies that provide containers and pick up
services). Needles should not be bent or broken prior to disposal.
75. Blood borne disease
To reduce the risk of disease transmission, the American Dental
Association (ADA), the Occupational Safety and Health Association
(OSHA), and the CDC have set standards of infection control for
dental health care personnel (DHCP)
Exposure to blood borne pathogens is significantly reduced via the
use of personal protective equipment (PPE) during dental treatment
76. The advent of rapid HIV screening technologies allows
the individuals to learn their HIV status approximately in
20 minutes, well within time frame of a routine dental
visit. If the rapid test is positive it should be followed up
with a confirmatory tests like western Blot or
immunofluorescence antibody.
77. Post exposure prophylaxis first aid should
be administered as necessary. Puncture
wounds and other injuries to the skin should
be washed with soap and water; mucous
membranes should be flushed with water . use
of antiseptics is not contraindicated. The
application of caustic agents (e.g., bleach) or
the injection of antiseptics or disinfectants into
the wound is not recommended.
78. To reduce the possibility of virus and other microorganisms
contaminating treatment water within dental hand pieces, ultrasonic
scales, or air/water syringes, these items should be discharged for
20-30 seconds after each patient’s visit and before next use (even if
a device is equipped with an anti retraction valve).
79. Air borne disease
The chain of aerobiological infection begins with the dispersion into
the air of bacteria and viruses.
The principle source of such contamination is the mouth with
saliva, blood, sub gingival fluids and moisture from the naso
pharynx constituting the largest reservoir of infectious organisms.
These fluids are projected into the air by coughing, sneezing and
general exhalation.
In a dental surgery, however, this process is exacerbated
significantly by the use of the high-speed instruments such as ultra
sonic scalers and drill
80. As a result of the droplets and the dust-borne
microorganisms, dental patients and dental health care
workers may be exposed to a variety of microorganisms
- via blood, oral or respiratory secretions. Such
pathogens may include Cytomegalovirus, hepatitis B
virus, hepatitis C virus, herpes simplex virus types 1 and
2, human immunodeficiency virus (HIV), Mycobacterium
tuberculosis, Staphylococci, Streptococci, and other
viruses and bacteria
81. In a calm room, for example, a droplet of 2
microns in diameter requires an average of 4.2
hours to settle.
surgery is equipped with an air conditioning or
a ventilation system, or if you simply open your
window, the microorganisms are rapidly
spread - often lifting from surfaces where they
have previously settled and floating freely
around the surgery and into other practice
rooms.
82. Decontaminating the air
Filtration Filtration or decontamination by filtration
forces air through a HEPA filter (high efficiency
particle arrestor). Used extensively in operating
theatres and other highly sensitive medical
environments, these filters have proved to be
effective in reducing airborne contamination. In
fact, the filters are capable of trapping particles as
small as 0.3 microns – sufficient to prevent the
majority of bacteria that measure between 0.1 and
10 microns
83. Ozonization
Ozonisation subjects the air to high voltage
charges.This results in the separation of
adjacent oxygen atoms which thus brings
about the creation of the ozone isotope.
84. Ionization
Ionisation uses charged electrodes to project
negative ions into the air; a process which
occurs in nature when lightning accompanies
a thunder storm.
The microorganisms floating in the air attract
these negatively charged ions, become
heavier as a result and then precipitate on to
surfaces
85. Sterilization
Only air sterilization assures the destruction of
aerobiological microorganisms via a single
process and without the creation of secondary
harmful waste.
When subjected to sustained ultraviolet
irradiation the DNA of all bacteria and viruses
are ruptured thus rendering them sterile and
incapable of reproduction
86. Limit the use of ultrasonic scalers and
highspeed handpieces in actively infected
patients.(Aerosolized M.tuberculosis can survive
more than nine hours). High volume suction is
mandatory for carrying out any procedure to
minimize aerosol generation.
87. Use a well constructed, soft pleated, high filtration face
masks. Standard face masks do not protect against TB
transmission, hence particulate face masks should be
used and often changed at regular intervals. Face
masks should have atleast 95% Bacterial filtration
efficiency (BPE) for particles 3μm diameter. While
treating patients with symptoms of active TB, the
operator should wear respirators rather than routine face
masks.
88. Clinical waste disposal:
Red indicates the anatomical waste;
yellow indicates waste which requires disposal by
incineration only;
black indicates domestic waste minimum
treatment/disposal required is landfill, municipal
incineration;
Blue is for medicinal waste for incineration;
White is for amalgam waste for recovery
89. Decontamination is the process of removal of
contaminating pathogenic microorganisms from the
articles by a process of sterilization or disinfection. It is the
use of physical or chemical means to remove, inactivate, or
destroy living organisms on a surface so that the organisms
are no longer infectious.
Sanitization is the process of chemical or mechanical
cleansing, applicable in public health systems. Usually
used by the food industry. It reduces microbes on eating
utensils to safe, acceptable levels for public health.
Asepsis is the employment of techniques (such as usage
of gloves, air filters, uv rays etc) to achieve microbe-free
environment.
Antisepsis is the use of chemicals (antiseptics) to make
skin or mucus membranes devoid of pathogenic
microorganisms.
90. CONCLUSION:
Pervasive increases in serious transmissible diseases
over the last few decades have created global concern
and impacted the treatment mode of all health care
practitioners. Emphasis has now expanded to assuring
and demonstrating to patients that they are well
protected from risks of infectious disease. Infection
control has helped to allay concerns of the health care
personnel and instill confidence and in providing a safe
environment for both patient and personnel.
91. References
Text book of Microbiology Anant Narayan.
Text book of Microbiology C P Baweja.
Rajasekar, et al.ijr Tuberculosis and precautions in
Dental office Volume 4 | Issue 1 | January 2017
Lakshya Rani et al /J. Pharm. Sci. & Res. Sterilization
Protocols in Dentistry – A Review Vol. 8(6), 2016, 558-
564
Sridhar Rao P.N et al Sterilization and Disinfection june
2008
Karen ward et al special report airborne contamination in
dentistry 2017
