Organic Name Reactions for the students and aspirants of Chemistry12th.pptx
sterilization-170117164543.pdf
1. Presented by Dr. Aishwarya Hajare
1st year post graduate student
1
2. Contents-
INTRODUCTION
TERMINOLOGIES
HISTORY
CLASSIFICATION
DETAILS OF INDIVIDUAL AGENTS
BIOLOGICAL CONTROLS
STERILIZATION IN DENTISTRY
STERILIZATION IN PERIODONTICS
INFECTION CONTROL
WASTE MANAGEMENT
RECENT ADVANCES IN STERILIZATION AND DISINFECTION
CONCLUSION
REFERENCES
2
3. Introduction
Microorganisms are ubiquitous.
Since pathogenic microorganisms cause contamination,
infection and decay, it becomes necessary to remove or
destroy them from materials and areas.
This is the objective of infection control and sterilization.
3
4. STERILIZATION Sterilization (or sterilisation) is a term referring to any
process that eliminates or kills all forms of life and other biological
agents including transmissible agents (such as fungi, bacteria, viruses, prions,
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.
( WHO Glossary )
STERILE: Free from all living microorganisms; usually described as a
probability (e.g., the probability of a surviving microorganism being 1 in 1
million).(CDC guidelines 2008)
4
5. DISINFECTION: Destruction of pathogenic and other kinds of
microorganisms by physical or chemical means. Disinfection is less lethal
than sterilization, because it destroys the majority of recognized pathogenic
microorganisms, but not necessarily all microbial forms (e.g., bacterial
spores).(CDC guidelines 2008)
Disinfection is a process of removing or killing most, but not all, viable
organisms.
MIMS-PLAYFAIR,5th
5
6. ANTISEPSIS is the prevention of infection, usually by
inhibiting the growth of bacteria in wounds or tissues
BACTERICIDAL AGENTS: Those which are able to kill
bacteria.
BACTERIOSTATIC AGENTS: Only prevents the
multiplication of bacteria which may however remain alive.
DECONTAMINATION: The process of rendering an article
or area free of danger from contaminants, including microbial,
chemical, radioactive and other hazards.
6
7. History of sterilization
Hippocrates of Cos (460-377 BC), was the first to separate medicine from
philosophy and disproved the idea that disease was punishment for sin. He
also advocated irrigation of wounds with wine or boiled water,
foreshadowing asepsis.
Ignaz Semmelweis, an Hungarian obstetrician, advocated in 1847 the value
of handwashing and fingernail scrubbing.
7
8. In 1862, French chemist and microbiologist
Louis Pasteur publishes his findings on how
germs cause disease, which he later uses to
develop the pasteurization process.
Joseph Lister, an English physician, reduced the
mortality rate of his patients in 1867 by using a
carbolic solution spray as he operated, he then
used it in the wound.
Charles Chamberland, Louis Pasteur’s pupil
and collaborator, developed the first pressure
steam sterilizer, or autoclave in 1876.
8
9. The research of Robert Koch and his associates in 1881 on the disinfecting
properties of steam and hot air mark the beginning of the science of
disinfection and sterilization. They devised the first non pressure flowing
steam sterilizer.
Aesculap created the first rigid instrument container, originally made of
stainless steel, in Germany. In the early 1900’s, responding to the needs of
the military hospitals and aid stations, Aesculap manufactured chrome-plated
containers for safe transport of sterile instruments..
9
10. METHODS OF STERILIZATION AND DISINFECTION
PHYSICAL METHODS
• SUNLIGHT
• DRYING
• DRY HEAT
• MOIST HEAT
• FILTRATION
• RADIATION
• ULTRASONIC AND SONIC
VIBRATIONS
CHEMICAL METHODS
• ALCOHOLS
• ALDEHYDES
• DYES
• HALOGENS
• PHENOLS
• SURFACE-ACTIVE
AGENTS
• METALLIC SALTS
• GASES
10
11. Sunlight:- Active germicidal effect due to the combined effect of U.V and heat
rays. e.g.:- river, tanks & lakes.
Drying:- 4/5ths of weight of bacterial cell consist of water and hence drying has
a deleterious effect on many bacteria.
Heat :- most reliable and commonly applied way of sterilization
Dry heat
11
Flaming:- Inoculating loops or wires, the tip of
forceps & needles and spatulas are held in a bunsen
flame till they become red hot in order to be
sterilized.
Incineration :- Rapidly destroying materials such as
soiled dressings, bedding, animal carcasses,
pathological materials etc.
PHYSICALAGENTS
13. HOT AIR OVEN:-
It’s the most widely used mode of sterilization
Temp.- 160°C ( 320° F ) for 1-2 hr.
Uses :-
- Glasswares like glass syringes, petridishes, flasks,
pipettes & test tubes.
- Surgical instruments like scalpels, scissors, forceps
etc..
- Chemicals such as liquid paraffin, fats, greases,
Sulphonamide, dusting powder etc. 13
14. Precautions:-
1) Not to be overloaded.
2) Must be fitted with fans for even distribution of
hot air.
3) Materials to be sterilized should be perfectly dry.
4) Rubber materials (except silicone rubber) will
not withstand the temperature.
5) Allowed to cool for 2 hrs before opening the
doors.
14
Advantage:
Economical.
Does not rust metals
Easily monitored .
Used for anhydrous
oils & powder.
Disadvantage :
Hot air is bad
conductor of heat
hence it has less
penetrating power
15. • pasteurisation of milk.
• Inspissation.
• Vaccine bath.
• Low temperature steam formaldehyde.
TEMPERATURE
BELOW 100O C
• Boiling
• Tyndallisation
• Steam sterilizer at 1000 C
TEMPERATURE
AT 100O C
• Autoclave
TEMPERATURE
ABOVE 100O
MOIST HEAT
15
16. AUTOCLAVING
Boiling water alone is INSUFFICIENT to kill spores and viruses
water boils when its vapour pressure equals to that of surrounding atmosphere
Hence, when pressure increases inside closed vessel
Temperature at which water boils increases
saturated steam has penetrative power
When steam comes in contact with a cooler surface it condenses to water
and gives up latent heat to that surface. The large reduction in volume of steam
sucks in more steam to the site and the process continues till the temperature of
article is raised to that of steam.
16
17. 17
AUTOCLAVE
Three major factors for effective autoclave:
1. Pressure: 15psi.
2. Temperature: 121oC
3. Time: 15 mins.
Higher temperature and pressure require shorter time
for sterilisation.
Pressure (psi)
• 15
• 20
• 20
Temperature
(°C)
• 121
• 126
• 134
Time (mins)
• 15
• 10
• 3
18. Types of autoclave
DOWNWARD DISPLACEMENT
Also known as Gravity displacement unit.
This is because of the method of air removal in the sterilization
chamber.
POSITIVE PRESSURE DISPLACEMENT
It’s an improvement over downward displacement autoclave.
Steam is created in a second, separate chamber and held until the
proper amount to displace all of the air in the sterilization
chamber is accumulated.
The steam is then released into the sterilization chamber in a
pressurized blast, forcing the air out through the drain hole and
starting the sterilization process
18
19. NEGATIVE PRESSURE DISPLACEMENT
one of the most accurate types of unit available
Once the sterilization chamber door is closed, a vacuum pump removes
the air.
Steam is created in a second, separate chamber.
Once the air has been completely removed from the sterilization
chamber, the steam is then released into the sterilization chamber in a
pressurized blast much like that of a positive pressure displacement unit.
The negative pressure displacement unit is able to achieve a high
"Sterility Assurance Level" (SAL), but the system can be quite large and
costly.
19
20. TRIPLE VACUUM AUTOCLAVE
A triple vacuum autoclave is set up/function in a
similar fashion to a negative pressure displacement.
This is repeated three times, hence the name "triple
vacuum" autoclave. This type of autoclave is suitable
for all types of instruments and is very versatile
20
21. Classification of a autoclave
Classification Suitable for Processing Used by
N Type (Downward
Displacement)
Unwrapped solid
instruments for immediate
use.
S Type (Vacuum) Items specified by the
autoclave manufacturer.
N.B. Eschmann units
suitable for naked and
single wrapped solid and
hollow items.
Medical Surgeries
Podiatrist
Tattooist
Body Pierces
B Type (Vacuum) Unwrapped & wrapped
solid and hollow
instruments. Porous loads,
e.g drapes & gowns.
Dentists
Plastic surgeons
Day surgeries
21
22. 1. Ensure complete air removal for temperature
to reach 121°C.
2. Ensure loose packing in the chamber.
3. Tightly sealed materials may become
dangerously pressurized causing injury when
removed.
22
Considerations during autoclaving
USES:
Disposable syringes, Non disposable syringes,
Glassware, Metal instruments, surgical dressing,
Surgical instruments, Laboratory equipment, Culture
media, Pharmaceutical products.
23. 23
Advantage:-
Economical.
Good penetration.
Short cycle time.
Easily monitored
No special chemicals
or exhaust required.
Disadvantage:-
Moisture retention
Causes corrosion
Carbon steel gets
damaged
Dulling of unprotected
cutting edges.
Destruction of heat
sensitive materials.
24. Filtration helps to remove bacteria from heat labile such as sera and solutions of
sugars or antibiotics used for preparation of culture media.
24
Candle Filter
Sintered Glass Filters Membrane Filters
Asbestos Filter
25. RADIATION
1) Non-ionising radiation:
Uses longer wavelength and lower energy. And hence lose
the ability to penetrate substances, and can only be used for
sterilizing surfaces
Eg. infrared radiation is used for rapid mass sterilization of
prepacked items eg. Syringes, catheters.
UV radiation is used for disinfecting enclosed areas like
operation theaters, laboratories.
2) Ionising radiation:
Uses short wavelength, high-intensity radiation with high
penetrative power to destroy microorganisms.
This radiation can come in the form of gamma or X-rays
that react with DNA resulting in a damaged cell.
Since there is no appreciable increase in the temperature, it
is also known as COLD STERILIZATION.
Used for sterilizing plastics, swabs, metal foils etc. 25
26. Gamma radiation
The Nature of Gamma Radiation -A form of pure energy that is
generally characterized by its deep penetration and low dose rates,
Gamma Radiation effectively kills microorganisms throughout.
Benefits of Gamma Radiation include:
1. precise dosing
2. rapid processing
3. uniform dose distribution
4. system flexibility
5. dosimetric release–the immediate availability of product after
processing.
Penetrating Sterilization: Even with High-Density Products Gamma
Radiation is a penetrating sterilant.
Substantial Decrease in Organism Survival: Gamma Radiation kills
microorganisms by attacking the DNA molecule. 26
27. ULTRASONIC and SONIC CLEANING
More effective than manual cleaning.
Removes dried serum, whole blood, plaque, zinc phosphate
and polycarboxylate cements from instruments, metal
surfaces and dentures.
Minimizes handling of contaminated instruments.
During cleaning, totally submerge instruments in the
ultrasonic solution for 2 to 20 minutes .
Ultrasonic solution should be changed atleast once a day.
27
28. Flash sterilization
“Flash” steam sterilization was originally defined by Underwood
and Perkins as sterilization of an unwrapped object at 1320C for 3
minutes at 27-28 lbs. of pressure in a gravity displacement
sterilizer.
Currently, the time required for flash sterilization depends on the
type of sterilizer and the type of item (i.e., porous vs non-porous
items).
Uses:
- Flash sterilization is considered acceptable for processing cleaned
patient-care items that cannot be packaged, sterilized, and stored
before use.
- It also is used when there is insufficient time to sterilize an item by
the preferred package method.
28
29. BIOLOGICAL CONTROLS FOR DIFFERENT
STERILIZATION METHODS
METHOD OF
STERILIZATION
BIOLOGICAL CONTROL
Hot Air Oven Bacillus subtilis subsp. Niger
Clostridium tetani
Autoclave Bacillus stearothermophilus
Filtration Serratia marcescens,
Pseudomonas diminuta
Ionizing Radiation Bacillus pumilis 29
30. CHEMICAL AGENTS
LIQUIDS GASES
• Alcohols
• Aldehydes
• Phenols
• Halogens
• Heavy Metals
• Surface Active Agents
• Dyes
• Formaldehyde
• Ethylene Oxide
• Plasma
30
31. Protein coagulation
Disruption of the cell membrane
Removal of the free sulphydryl groups
Substrate competition
31
32. CLASSIFICATION
OF INSTRUMENTS
Critical
instruments
Semi-critical
Instruments
Non-critical
Instruments
32
Penetrate the soft tissue
Contact the bone
Enter into or contact the
blood stream
They should be
thoroughly cleaned and
heat sterilized if they are
to be reused.
Eg: Surgical instruments,
Scalers, Scissors
Surgical dental burs
Scalpel blades
Forceps
Bone grafts
Contact the mucous
membrane but will not
penetrate the soft
tissue
Eg : Mouth mirror,
impression trays,
handpieces, probe,
tweezers
Come into contact
with intact skin
Eg : X-Ray tubes, Light
handles, Counter tops
34. ALCOHOL
Mechanism of Action : Denaturation of Proteins
Isopropyl alcohol
70% ethyl alcohol
Ethyl alcohol is active against the fungal
spores and used to treat cabinets and
incubator
Suitable for skin preparation before
venepuncture
Disadvantage : . Inflammable
. Mucous membrane irritant.
. Promotes rusting.
34
Used as a skin
disinfectant
35. 35
A)Formaldehyde (formalin)
In aqueous solution it acts as a bactericidal and sporicidal
Active against Gram -ve bacteria, spores, viruses (HB, HIV) & fungi
Aqueous soultion: Formalin(37% solution) - 10% formalin +
0.5% Na tetraborate used to clean metal instrument e.g.
Endoscope, dialysis equipment.
Gaseous form: Fumigation of wards/corridors/ICU’s
DISADVANTAGE: Have pungent odour & irritating effect on
skin & mucous membrane.
ALDEHYDES
36. High level disinfectant
Especially active against tubercle bacilli,f ungi
and viruses
Less toxic than formaldehyde
Can be safely used to treat corrugated rubber
anaesthetic tubes, face masks, metal instruments.
Exposure time: > 10hrs.
36
B.GLUTARALDEHYDE / CIDEX ( 2% alkaline NaHCO3)
37. PHENOLS:
Acts by cell membrane damage thus releasing cell contents and
causing lysis
Eg. Cresol ( LYSOL) ,chlorhexidine ( SAVLON),chloroxylenol
(DETTOL)
Phenol is commonly found in mouthwashes, scrub soaps and
surface disinfectants
Low efficiency disinfectant
Used for decontamination of the hospital environment, including
laboratory surfaces, and noncritical medical items.
37
38. HALOGENS :
A) Chlorine compounds:
Bleaching powder or hypochlorite solution
mostly used disinfectant for HIV infected
material.
in concentration of 0.05 or 0.5% used for
surface material and instruments disinfection
Should be prepared daily because of
instability of sodium hypochlorite solution
Active against bacteria, spores, fungi and
viruses (HB, HIV) 38
39. B) IODOPHORS & IODINE
Active against bacteria, spores & some
viruses & fungi
Suitable for skin preparation, mouthwash &
as a surgical scrub
(7.5% Povidone+iodine= Betadine)
39
40. SALTS
Salts of heavy metals have toxic effect on bacteria.
The salts of copper , silver and mercury are used as disinfectant.
SURFACE ACTIVE AGENTS
substances which alter energy relationships at
interfaces,producing a reduction of surface tension, are known as
surface active agents. E.g. quaternary compounds
40
41. ETHYLENE OXIDE
• Highly inflammable and in concentration more than 3% highly
explosive and hence not used for fumigation of rooms
• Mix with carbon dioxide or nitrogen to eliminate its explosive
tendency
• Effective against all types of micro-organism including
viruses and spores.
41
44. The four accepted methods of sterilization in dental offices
are:
Steam pressure sterilization (autoclave)
Chemical vapor pressure sterilization(chemiclave)
Dry heat sterilization(dryclave)
Ethylene oxide(ETOX) sterilization
44
45. It is performed in a steam autoclave. For light load of instruments
the time required at 121o C is 15 minutes at 15lbs of pressure. It
works on principle as that of pressure cooker.
Advantages: rapid and effective.
Disadvantages: items sensitive
Tends to rust carbon steel instruments and burs.
Sterilization of burs in autoclaves.
burs can be protected by keeping them submerged in small amounts
of 2% sodium nitrite solution.
Steam pressure sterilization(autoclave)
45
46. Performed in a chemiclave.
Operate at 131oC and 20lbs of pressure. they are similar to steam
sterilizer and have cycle of 30minutes.
• carbon steel and other corrosion sensitive instruments and pliers
are sterilized without rust or corrosion.
• items sensitive.
The 1938 patent of Dr. George Hollenback and the work of
hollenback and harvey in 1940s culminated in the development of
an unsaturated chemical vapor system , also called harvey
chemiclave.
Chemical vapor pressure sterilization
46
47. Advantages
1. Carbon steel and other
corrosion-sensitive
instruments are said to be
sterilized without rust.
2. Relatively quick turnaround
time for instruments.
3. Load comes out dry.
4. Sterilization is verifiable.
Disadvantages
1. Items sensitive to the
elevated temperature will be
damaged. Vapor odor is
offensive, requires aeration.
2. Heavy cloth wrappings of
surgical instruments may not
be penetrated to provide
sterilization.
47
48. Conventional dry heat ovens
Short cycle, high temperature dry heat oven.
They have heated chambers that allow air to circulate by gravity flow.
A rapid high temperature processing that uses forced draft oven(air circulates with a
fan or blower)
Operate at approximately 188oC-191oC
Dry heat sterilization
48
49. Advantages
1.Reasonable price
2. carbon steel instruments and
burs do not rust or corrode or lose
temper or cutting edges.
3. Rapid cycles possible at high
temperatures
Disadvantages
1.rubber and plastic materials
might damage.
2. heavy load of instruments
defeats sterilization.
3. Improper calibration may
damage instruments
49
50. Etox sterilization is the best method for sterilizing complex
instruments and delicate materials.
Advantages
Operates effectively at low temperatures
Gas is extremely penetrative
Can be used for sensitive equipment like handpieces.
Sterilization is verifiable
Disadvantages
Potentially mutagenic and carcinogenic.
Requires aeration chamber ,cycle time lasts hours
Usually only hospital based.
Ethylene oxide sterilization
50
51. OPERATORY ASEPSIS
In the dental operatory, operatory surfaces that are
repeatedly touched or soiled are best protected with
disposable covers(barriers)that can be discarded after
each treatment.
For dental unit trays, paper, plastic film or surgical pack
wraps (paper or towels) should cover the entire tray.
Clear plastic 15-gallon waste container bags fit many
chair backs , control units , and x-ray equipment.
Plastic restaurant silverware bags it suction handles and
air water syringe handles.
51
52. Gigasept which contains succindialdehyde and
dimethoxytetrahydrofuran are used for disinfection of
plastic and rubber materials eg: dental chair
52
53. Asepsis of surgery theaters
Fumigation is done by two methods:
1. Electric boiler method- 500 ml of formaldehyde
(40%) added to distilled water in electric boiler.
When the water heats fumes are generated.
2. Potassium permanganate – heat is induced by
oxider action of potassium permanganate. 500ml
of formaldehyde is added to potassium
permanganate which reacts and generates fumes.
53
54. DENTAL RADIOGRAPHY
CDC(MMWR),dec19,2003vol.52
• Contamination of working area occurs from saliva.
• X-ray tube head, exposure selector and timer button are likely to get
contaminated by saliva.
• Precaution to be taken up :
1. Put on gloves.
2. Place the film packets and film holders in special tray.
3. Contaminated films(exposed films) to be placed in separate tray.
54
55. 4. Film holding device to be rinsed in running water to remove
saliva.
5. Metallic part to be autoclaved.
6. Plastic attachments to be kept in chlorhexidine solution.
7. Wipe the x-ray tube head, exposure selector, timer button and film
packets with detergents.
8. Tube can be wrapped in disposable plastics.
9. Film packets to be discarded in yellow bags.
55
56. BIOPSY SPECIMEN
CDC(MMWR),dec19,2003vol.52
• Biopsy collection & transportation can also be a source of
infection.
• It should be kept in sturdy containers with secure lid.
• Avoid contaminating the external surface of the container.
• Swab used for collecting micro-organisms should be
transferred slowly and carefully to the swab container.
56
57. • BIO-FILMS :
CDC(MMWR),dec19,2003vol.52
• Tubes connecting hand-pieces, air/water syringe &
ultrasonic scaler unit are harbor of wide range of
micro-organisms.
• They colonize and replicate on the inner surface of
tubings.
• They serve as reservoir for micro-organisms.
57
58. Following measures should be taken to prevent this :
A) Anti-retraction valves : (one way flow check valve). To prevent
transfer or aspiration of potentially infected material in the tubings.
B) Bacterial filter : Filters to be fitted in water lines of hand-pieces &
water syringes.
C) Chemical Disinfectants : Tubings are flushed with disinfectants like
sodium hypochlorite.
D) Aspirators : Cleaned and flushed after every patient for 20 – 30
secs.
To be flushed with disinfectant at the end of the day.
58
60. DENTAL CASTS
CDC(MMWR),dec19,2003vol.52
Spraying until wet or
Immersing in a 1:10
dilution of sodium
hypochlorite or an
iodophor then rinse
Casts to be disinfected
should be fully set (i.e.
stored for at least 24
hours)
60
ADA recommends use of
Chlorine compounds
Iodophors
Combination of synthetic
phenols
Glutaraldehyde.
61. • Sterilize instruments like articulators, wax knives, spatula, shade
guide, acrylic bur etc.
• Custom impression trays, base plates, occlusal rim and all other
prosthesis must be disinfected, after construction & before use in
patient.
• Articulators, casts, base plates to be disinfected by 1:10 chlorine
solution following each session or before returning to laboratory.
• Dentures washed & soaked in sodium hypochlorite for 5 mins before
delivery.
61
62. ROTARY INSTRUMENTS - BURS
Diamond and carbide burs:
After use they are placed in 0.2%
gluteraldehyde and sodium phenate (Eg.
Sporicidin) for at least 10 minutes,
cleaned with a bur brush or in an ultrasonic
bath.
Sterilize in an autoclave or dry heat
Steel burs:
May get damaged by autoclaving. Can be
sterilized by using a chemical vapor sterilizer or
glass bead sterilizer at 2300C for 20-30 seconds.
62
63. ENDODONTIC INSTRUMENTS
CDC(MMWR),dec19,2003vol.52
• Glass Bead or salt sterilizer is the best option, but they do not
sterilize the handle.
• Sterilization achieved in 10 seconds
• Dry heat is used, with instruments in closed metal or perforated
metal boxes.
• Sterilization achieved at 218oC for 15 seconds
• Gutta percha points are pre-sterilized.
• Contaminated points are sterilized by 5.25% sodium
hypochlorite.(1 min immersion).
• Then rinse with hydrogen peroxide & dry it. 63
64. • Silver cones sterilized by passing slowly over the flame for
3-4 times.
• Can also be sterilized in hot salt sterilizer.
• Files to be handled with tweezer.
• Glass slab is sterilized by swabbing the surface with
tincture of thiomersal, followed by swabbing with alcohol.
• Cement spatula is sterilized by flamming 3 or 4 times over
bunsen flame.
64
66. IMPLANTS
Pre sterilized with Gamma radiation
In case the implants needs to be re-sterilized conventional
sterilization techniques are not satisfactory
Steam sterilization should not be used as it results in contamination
of surfaces with organic substances
Dry heat sterilization also leaves organic and inorganic surface
residue
Radio frequency glow discharge technique (RFGDT) or Plasma
cleaning is used.
In this, material to be cleaned is bombarded by high energetic ions
formed in gas plasma in a vacuum chamber.
Removes both organic and inorganic contaminants.
66
67. Sterilization in periodontal clinic
All diagnostic instruments are sterilized by washing in korsolex and
sterilized.
Periodontal instruments
SHARP
e.g. knives,
scissors,
Files
Tissue holding forceps
BLUNT
Mouth mirrors,
tweezers,
artery forceps,
suture holding forceps
Periosteal elevator
67
68. Sharp instruments are ideally sterilized by :
conventional hot air oven
by not sterilized:
Boiling
Autoclave
2% glutaraldehyde
Blunt instruments are sterilized by
Autoclave
68
69. Sutures
Sutures are pre sterilized by gamma radiation
Sutures are re- sterilized by two recommed methods are
1. Soak for a full 10 minutes completely immersed in
povidone iodine 10% solution, then rinse in sterile
saline/water.
2. Ethylene Oxide – gas sterilisation.
Sterilising/disinfecting by other methods (autoclaving,
boiling, alcohol-soaking) are not recommended.
Glutaraldehyde has been taken off the market since May
2002. It was never intended to be a suture soaking solution
due to its high toxicity and the inability to ensure that all the
solution is rinsed off before use
69
70. ULTRASONIC SCALERS
CDC(MMWR),dec19,2003vol.52
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 inserts 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 considered
ineffective methods with risk of damage to materials as per American
Dental association Supplement to J.A.D.A. 8/92.
70
71. Effect of sterilization on
instruments
Sterilization Type of instrument
Stainless steel Carbon steel
Saturated steam at 250°F Amorphous substance
formed near cutting edge;
no dulling.
Dulling and oxidation of
cutting surfaces
Formalin-alcohol vapor at
270°F
Cracking of wire edge; no
dulling.
Some oxidation of
surfaces; no dulling.
Dry heat at 320°F Chipping of wire edge; no
dulling.
No visual change.
Dry heat at 340°F Chipping of wire edge; no
dulling.
No visual change
Effects of Sterilization on Periodontal
Instruments Roger B. Parkes,* and Robert A.
Kolstadf Accepted for publication 31 August
1981 71
72. Recent advances in sterilization and
disinfection
Various new methods of sterilization are under investigation and
development.
Peroxide vapor sterilization - an aqueous hydrogen peroxide
solution boils in a heated vaporizer and then flows as a vapor into
a sterilization chamber containing a load of instruments at low
pressure and low temperature
Ultraviolet light - exposes the contaminants with a lethal dose of
energy in the form of light. The UV light will alter the DNA of
the pathogens. Not effective against RNA viruses like HIV.
72
73. Plasma Sterilization
Plasma is basically ionized gas. When you apply an
electric field to a gas, it gets ionized into electrons and
ions.
Plasma is usually comprised of UV photons, ions,
electrons and neutrals.
A plasma is a quasi-neutral collection capable of
collective behavior
Their combined photolytic, chemical and electric
action efficiently kills most micro-organisms.
74. Ozone
Ozone sterilization is the newest low-temperature
sterilization method recently introduced in the US and is
suitable for many heat sensitive and moisture sensitive or
moisture stable medical devices
Ozone sterilization is compatible with stainless steel
instruments.
Ozone Parameters • The cycle time is approximately 4.5
hours, at a temperature of 850F – 940F.
74
75. Newer Disinfectants
Persistent antimicrobial-drug coating that can be applied to inanimate and
animate objects containing silver (Surfacine)
A high-level disinfectant with reduced exposure time (ortho-
phthalaldehyde)
An antimicrobial drug that can be applied to animate and inanimate objects
(superoxidized water)
77. BASIC CONCEPT OF INFECTION CONTROL
Prevent spread of infection from the Clinician to
the patient
Prevent the spread of infection from the Patient
to the Clinician
Prevent the spread of infection from one patient
to another
77
Patient
Operator
Other
personnel
67
78. For routine dental examination procedures, hand washing is achieved
by using either a plain or antimicrobial soap and water.
The purpose of surgical hand antisepsis is to eliminate transient flora
and reduce resident flora to prevent introduction of organisms in the
operative wound, if gloves become punctured or torn.
At the beginning of a routine treatment period, watches and jewelry
must be removed and hands must be washed with a suitable cleanser.
Hands must be lathered for at least 10 seconds, rubbing all surfaces and
rinsed.
Clean brushes can be used to scrub under and around the nails.
Must be repeated at least once to remove all soil.
78
82. Hegde et al in their study stated that the bar soap under
the "in use" condition is a reservoir of microorganisms
and washing hands with such a soap may lead to
spread of infection. (Microbial contamination of "in
use" bar soaps in dental clinics. Indian J Dent Res
2006;17:70-3)
82
67
85. Masks
Types:
1. Surgical masks (required to have
fluid-resistant properties).
1. Procedure/isolation masks
Made up from a melt blown placed between non-woven fabric
Layers of a Mask
1. an outer layer
2. a microfiber middle layer - filter large wearer-generated particles
3. a soft, absorbent inner layer - absorbs moisture.
Available in 2 sizes: regular and petite.
85
86. N95 PARTICULATE RESPIRATOR
National Institute for Occupational Safety and
Health (NIOSH) introduced a rating system which
identifies the abilities of respirators to remove the
most difficult particles to filter, referred to as the
most penetrating particle size (MPPS), which is
0.3µm in size.
The “N” means “Not resistant to oil”.
N95: captures at least 95% of particles at MPPS.
N99: captures 99% of particles at MPPS.
N100: captures 99.97% of particles at MPPS.
86
87. When should I wear an N95
respirator?
N95 particulate respirator 87
88. 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
88
89. Over garments
Gown type Situation and Rationale
Cotton/linen, reusable or disposable, long-
sleeved isolation gowns
Use if contamination of uniform or clothing is
likely or anticipated
Fluid resistant isolation gown or plastic apron
over isolation gown
Use if contamination of uniform or clothing
from significant volumes of blood or body fluids
is likely or anticipated (fluids may wick through
non-fluid resistant reusable or disposable
isolation gowns)
Fluid impervious gowns e.g., Gortex® Use if extended contact or large volume
exposure (e.g., large volume blood loss during
resuscitation of MVA victim or surgical assist)
89
90. Footwear
Most hospitals have their own policies regarding footwear.
Footwear with open heels and/or holes across the top can
increase the risk of harm to the person wearing them due to
more direct exposure to blood/body fluids or of sharps being
dropped for examples.
90
91. OCCUPATIONALLY ACQUIRED INFECTIONS
HIV : 0.3%
Hepatitis C : 1.8%
Hepatitis B (HBeAg +ve) : 30%
Occupational exposures that may result in HIV, HBV,
or HCV transmission include needlestick and other
sharps injuries; direct inoculation of virus into
cutaneous scratches, skin lesions, abrasions, or burns;
and inoculation of virus onto mucosal surfaces of the
eyes, nose, or mouth through accidental splashes
All health care professionals should be immunized
against Hepatitis A, Hepatitis B, Varicella, MMR, DPT,
Rubeola, Meningitis, Polio, Influenza, Tetanus,
Diptheria, Rubella.
91
67
92. Post exposure prophylaxis-HIV
Wound care:
Clean wounds with soap and water
Flush mucous membrane with water.
No evidence of benefit for: – application of antiseptics or
disinfectants
– squeezing puncture sites
Chemoprophylaxis
Initiating occupational 4 week regimen of PEP
(zidovudine+ lamivudine+nevirapine)as soon as
possible, ideally within 2 hours of exposure.
HIV- antibody testing should be performed for atleast 6
months post exposure
92
67
93. HIV Infection Control
(OSHA regulations)
• Measures at the time of Surgery :
• Proper hand washing.
• Surgical attire for operation theater.
• Cover the operation table with waterproof &
disposable sheet.
• Patient to be posted at the end of the operation list.
• Staff with laceration or abrasion on their hands are
excluded from the theatre.
93
94. • Number of staff member to be kept minimum.
• Separate members outside the operation theater for fetching the
drugs, equipments etc.
• Disposable foot covers, caps, mask, plastic gowns and protective
eye wear.
• Wearing of double gloves.
• Face mask or cap, if contaminated with splatter of blood, should
be replaced immediately.
• Scissors & diathermy should be used instead of blade or
scalpels.
94
95. • Sharp instruments not to be handed directly, but to be
delivered via kidney tray.
• Patient allowed to recover in operation theater instead of
recovery room and directly transferred to ward.
• In case of spillage of blood or body fluid, it should be
moped up using gloves and old linen/paper towel or news
paper.
• Sent for incineration in plastic bag.
• Area to be covered with 1% sodium Hypochlorite.
• Floor is wiped with soap and water followed by 1% sodium
hypochlorite.
95
96. • Gloves removed at last after removing mask, cap and
gowns.
• All sharp instruments kept in puncture proof plastic
container.
• Proper labeling done & sent for incineration.
• Needles to be capped before shredding.
• Non sharp waste kept in large plastic bag, labeled and
sent for incineration.
• Reusable instruments autoclaved.
• Then washed with soap and water.
• Re-autoclaved.
96
97. • Non-autoclavable instruments immersed in 2%
glutaraldehyde solution for 1 hour.
• Then cleaned with warm water and detergents.
• Again soaked in glutaraldehyde for 3 hours.
• Suction bottle should contain 30 ml of 2%
glutaraldehyde or 60 ml of 1% sodium hypochlorite.
• It is carefully emptied out, rinsed and autoclaved after
surgery.
• Ventilator tubes rinsed in running tap water and
immersed in 2% glutaraldehyde for 2 hours.
97
98. • Laboratory specimen placed in 10 % formalin jar,
with tight leak proof cork.
• It is kept in a bag and tightly closed and sealed, before
transportation to laboratory.
• Operating table, floor and walls to be thoroughly
cleaned with 1% sodium hypochlorite.
• Equipments or surfaces that cannot be easily
disinfected are covered with aluminium foil or
disposable plastic covers during surgery.
98
99. • Measures for Health Care workers (OSHA regulations)
A proper staff education and training.
Vaccination of all employees.
• Universal precautions to be observed.
• Proper hand washing.
• Careful handling of sharp objects & instruments.
• Proper sterilization, disinfection or disposal of
instruments after use.
• Use of gloves, mask, gowns etc.
99
100. 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 instruments or basket of instruments into an
ultrasonic cleaning device, rinse them, and then carefully
inspect the instruments for debris.
instruments likely to rust , dip into a rust inhibitor solution.
Drain & dry instruments with absorbent towel.
100
103. Effect of sterilization on
instruments
Sterilization Type of instrument
Stainless steel Carbon steel
Saturated steam at 250°F Amorphous substance
formed near cutting edge;
no dulling.
Dulling and oxidation of
cutting surfaces
Formalin-alcohol vapor at
270°F
Cracking of wire edge; no
dulling.
Some oxidation of
surfaces; no dulling.
Dry heat at 320°F Chipping of wire edge; no
dulling.
No visual change.
Dry heat at 340°F Chipping of wire edge; no
dulling.
No visual change
Effects of Sterilization on Periodontal
Instruments Roger B. Parkes,* and Robert A.
Kolstadf Accepted for publication 31 August
1981 103
104. • Divided into two categories :
A) Bio-hazardous materials.
B) Non-bio-hazardous materials.
A) Bio-hazardous materials consist of waste materials :
– 1. Soaked with blood or other body secretions.
– 2. Capable of causing infectious disease.
– 3. Having a poisonous effect.
– 4. Human tissue removed during surgery.
– 5. Teeth and associated tissues.
– 6. Gloves.
104
Waste management
106. Waste Management
Categories of bio-medical waste in india
Options Waste category
Category 1 Human anatomical
waste(tissues
,organs,body parts)
Category 2 Animal waste
Category 3 Microbiology and
biotechnology waste
Category 4 Waste sharps
(needles,syringe,sca
lpels…)
Category 5 Discarded medicine
and cytotoxic drugs
106
67
107. Waste Management
Category 6 Solid waste(items contaminated
with blood and fluid including
cotton dressing….)
Category 7 Solid waste (waste generated
from disposable items )
Category 8 Liquid waste(waste generated
from laboratory and washing
cleaning …)
Category 9 Incineration ash
Category 10 Chemicals used in production of
biological, chemical used in
disinfection
107
67
108. COLOUR CODES
COLOUR TYPE OF
CONTAINER
WASTE
CATEGORY
TREATMENT
OPTIONS
YELLOW PLASTIC BAGS Human and animal
wastes, Microbial
and
Biological wastes
and soiled
Wastes, eg. human
tissues, body
parts, organs,
lab cultures,
specimens,
items
contaminated
with blood
Incineration,
deep burial
RED DISINFECTED
CONTAINER/PLAS
TIC BAGS
Microbiological and
Biological wastes,
Soiled wastes,
Solid waste,
eg.
Disposable
items like
catheters, IV
Autoclave,
microwave,
chemical burial
108
109. COLOUR CODE TYPE OF
CONTAINER
WASTE
CATEGORY
TREATMENT
OPTIONS
BLUE/WHITE
TRANSPARENT
PLASTIC
BAG,PUNCTURE
PROOF
CONTAINER
Waste sharps
and solid waste,
eg. .Sharps,
needles ,
scalpels,
disposable
items like
catheter, IV set
etc
Autoclave/
Microwave
/
Chemical
Treatment
Destructio
n
BLACK PLASTIC BAG Discarded
medicines,
incinerated
ashes,
chemicals used
for disinfection
etc.
DISPOSAL IN
SECURED LAND
FILLS
109
110. CONCLUSION
A steady increase in the serious transmissible diseases over the
last few decades have created a 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.
The dental health care provider has to follow high standards of
infection control for the safety of the patients and the dental
health care workers
110
67
111. References
Texbook of microbiology by Prof. CP Baveja.(3rd edition)
Operative dentistry chp- infection control by
Studervant.(4th edition)
Essentials of preventive and community dentistry Soben
peter (3rd edition)
Textbook of clinical periodontology, Newman, Takei,
Carranza, 11th edition.
WHO glossary
Article on Sterilization of Suture material by Ingrid Cox
dated 2004 17(50) from Community Eye Health Journal.
Article on effects of sterilisation on periodontal instruments
by Roger B. Parkes and Robert A. Kolstadf Accepted for
publication 31 August 1981 Journ Periodont
Article on recent advances in sterilization by William
A.Rutala and David Weber( Emerging Inectious Diseases
111
112. Sterilization and disinfection of dental instruments by ADA
Disinfection & sterilization of dental instruments TB MED
266, 1995
CDC, guidelines for disinfection & sterilization in health
care facilities 2008.
Infection prevention and control, college of respiratory
therapists Ontario, june 2011
New CDC guidelines for selected infection control
procedures, chris miller.
CDC guidelines for infection control in dental health care
settings, Dec19, 2003/vol.52.
Sterilization of ultrasonic inserts
112
