sterilization and disinfection

1. PRESENTED BY :
DR.AKANKSHA SINGH
{PG 1ST YEAR}

2.  TERMINOLOGIES
 HISTORY
 CLASSIFICATION
 SPAULDING’S CLASSIFICATION
 DETAILS OF INDIVIDUAL AGENTS
 BIOLOGICAL CONTROLS
 STERILIZATION IN DENTISTRY
 STERILIZATION IN PERIODONTICS
 INFECTION CONTROL
 COVID IN DENTISTRY
 WASTE MANAGEMENT
 RECENT ADVANCES IN STERILIZATION AND DISINFECTION
 CONCLUSION
 REFERENCES

3.  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.

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 )
It is a process by which an article ,surface,or medium is made free of all
microorganisms either in vegetative or spore form.
C.P.Baveja(4th edition)

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)
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)

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.

7.  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.
 “the golden age of microbiology”-mid to late 1800
 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.

8. • 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

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.
• Moden inection control reccommendations &sterilization
guidelines were stated by centre for disease control in
1973
• Comprehensive guidelines for infection control came into
effect in dec.1991

10. PHYSICAL METHODS CHEMICAL METHODS
• SUNLIGHT
• DRYING
• DRY HEAT
• MOIST HEAT
• FILTRATION
• RADIATION
• ULTRASONIC AND
• SONIC VIBRATIONS
• ALCOHOLS
• ALDEHYDES
• DYES
• HALOGENS
• PHENOLS
• SURFACE-ACTIVE
AGENTS
• METALLIC SALTS
• GASES
(ANANTHNARAYAN & PANIKER’S)
7TH EDITION

11. CDC GUIDELINES [2008]

12. CLASSIFICATION OF INSTRUMENTS
NON CRITICAL
INSTRUMENTS
SEMI CRITICAL
INSTRUMENTS
CRITICAL
INSTRUMENTS
• 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

13. LEVEL OF DISINFECTION
Level of
disinfection
Items Time Disinfectant
High level Critical and
semicritical items
(except
thermometers and
hydrotherapy tanks)
>=20 min.
(sterilization x ,then
hld)
Gluteraldehyde,hydr
ogen
peroxide,peracetic
acid,chlorines
Intermediate level Semicritical and
noncritical(except
environmental
surfaces)
<=10 min. Alchohols,iodophore
s,phenolics,chlorine
s,
Low
level(environmental
surfaces)
noncritical Alchohols,iodophore
s,phenolics,chlorine
s
Soben peter

15. Sunlight
• Active germicidal effect due to the combined
effect of U.V and heat rays.
• It plays an important role in spontaneous
sterilization that occurs in natural conditions.
Drying
• Moisture is essential for bacteria
• 4/5ths of weight of bacterial cell consist of water
and hence drying has a deleterious effect on
many bacteria.
• Viruses and spores are unaffected by drying

16. HEAT
FLAMIMG
INCINERATION
HOT AIR OVEN
DRY HEAT
MOIST HEAT
•TEMP. BELOW
100DEGREE
•TEMP. AT 100 DEGREE
•TEMP. ABOVE 100
DEGREE

17. Principle- -
 Protein denaturation.
 Oxidative damage.
 Toxic effects of elevated levels of
electrolytes.

18. INCINERATION
 Rapidly destroying materials such
as soiled dressings, bedding,
animal carcasses, pathological
materials etc. by burning to
prevent spread of infection..
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.

19. 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.

20. Precautions:-
• Not to be overloaded.
• Must be fitted with fans for even distribution of hot air.
• Materials to be sterilized should be perfectly dry.
• Rubber materials (except silicone rubber) will not withstand the temperature
• Allowed to cool for 2 hrs before opening the doors.
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

21. MOIST HEAT
TEMPERATURE
BELOW 100 C
• Pausterization of
milk
• Insipassation
• Vaccine bath
• Low temperature
steam
formaldehyde
TEMPERATURE
AT 100 C
• Boiling
• Tyndallisation
• Steam sterilizer at
100⁰c
TEMPERATURE
ABOVE 100 C
• autoclave

22. Inspissation
 Some serum or egg media,such
as Lowenstein-Jensen and
loeffler’s serum,are rendered
sterile by heating at 80-85⁰c
temp. For half an hour
Pausterization
Two types of method:
Holder method:-63⁰ c for 30 min.
Flash method:-72⁰ c for 20 seconds
followed by cooling quickly to 13⁰ c
or lower

23. Steam sterilizer
 Steam at 100⁰c for 90 min.
 Koch and Arnold’s steam
sterilizer used for media which are
decomposed at high temp. of
autoclave
Tyndallisation
 Steam at 100⁰c for 20 min. on 3
consecutive days
 Principle:-first exposure kills all
vegetative forms, in the intervals
between te heatingthe remaining
spores convert into vegetative
forms
 Used for egg, serum, or sugar
media

24. PRINCIPLE
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

25. Three major factors for effective
autoclave:
1. Pressure: 15psi.
2. Temperature: 121⁰C
3. Time: 15 mins.
 Higher temperature and
pressure require shorter time
for sterilization.
Components of autoclave:-
pressure
• 15
• 20
• 20
temperature
• 121
• 126
• 134
time
• 15
• 10
• 3

26. Classification of autoclave

27. 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

28. 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.

29. 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
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
Considerations during autoclaving:

30. USES:
• Disposable syringes,
• Non disposable syringes,
• Glassware,
• Metal instruments,
• surgical dressing,
• Surgical instruments,
• Laboratory equipment,
• Culture media,
• Pharmaceutical products.
advantages
•Economical
•Good
penetration
•Short cycle
time
Early monitored
No social
chemical or
exhaust required
disadvantages
Moisture
retention
Causes
corrosion
Carbon steel
gets damaged
Dulling of
unprotected
cutting edges
Destruction of
heat sensitive
materials

31. Filtration
It helps to remove bacteria from heat labile such as sera and
solutions of sugars or antibiotics used for preparation of culture
media.
Mechanism:a negative or positive pressure is necessary to
draw the fluid through filter into a sterile container
Membrane filter
Asbestos filter
Sintered
glass
filter
Candle
filter

32. 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.

33. 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.

34. 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

35. ULTRASONIC AND SONIC
CLEANING DEVICES
 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.

36. 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.

37. Chemical
agents
liquid gases
• Alchohol
• Aldehyde
• Phenol
• Halogen
• Heavy
metals
• Surface
active agents
• dyes
• Formaldehyde
• Ethylene Oxide
• Plasma

38. MODE OF ACTION OF
CHEMICALAGENTS
 Protein coagulation
 Disruption of the cell membrane
 Removal of the free sulphydryl groups
 Substrate competition

39. 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.

40. ALDEHYDES
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.

41. B.GLUTARALDEHYDE / CIDEX ( 2% alkaline
NaHCO3)
• High level disinfectant
• Especially active against tubercle bacilli, fungi and
viruses
• Less toxic than formaldehyde
• Can be safely used to treat corrugated rubber
anaesthetic tubes, face masks, metal instruments.
• Exposure time: > 10h

42. 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.

43. 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)

44. B) IODOPHORS & IODINE
 Active against bacteria, spores & some viruses &
fungi
 Suitable for skin preparation, mouthwash & as a
surgical scrub
(7.5% Povidone+iodine= Betadine)

45. 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

46. 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

47. RECOMMENDED CONCENTRATIONS
DISINFECTANT CONCENTRATION
Ethyl alchohol 70%
glutaraldehyde 2%
lysol 2.5%
savlon 2%
dettol 4%
Bleaching powder(calcium
hypochlorite)
14 gm in 1 L
Sodium hypochlorite 1%,0.1%
Betadine(iodophore) 2%

48. STERILISATION
AND
DISINFECTION
IN DENTAL
CLINIC

49. The four accepted methods of sterilization in dental offices
are:
1. Steam pressure sterilization (autoclave)
2. Chemical vapor pressure sterilization(chemiclave)
3. Dry heat sterilization(dryclave)
4. Ethylene oxide(ETOX) sterilization

50. Chemical vapor pressure
sterilization
 Performed in a chemiclave.
 Operate at 131⁰C 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.

51. Advantages
1. Carbon steel and other corrosion-
sensitive instruments are said to be
sterilized without rust.
2. Relatively quick turn around 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

52. Dry heat sterilization
 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 188⁰C-191⁰C
 Sterilization time is 6 minutes for unwrapped instruments and 12
minutes for wrapped instruments

53. 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

54. Ethylene oxide sterilization
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

55. 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.

56.  Plastic restaurant silverware bags it suction handles and
air water syringe handles
 Gigasept which contains succindialdehyde and
dimethoxytetrahydrofuran are used for disinfection of
plastic and rubber materials eg: dental chair

57. 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.

58. 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

59. 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.

60. Impression trays are sterilized as follows:
metallic - autoclave
plastic – ethylene oxide
Disinfection of alginate impressions –
Methods
-Spraying
- Immersion
Iodophors, sodium hypochlorite (1:10 concentration ) ,
phenols, formaldehyde, glutaraldehyde.

61. 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 218⁰C 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.

62.  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

63. -Cross infection control,journal of dental nursing

64. 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.

65. • Texbook of microbiology by Prof. CP Baveja.(3rd edition)
• Operative dentistry chp- infection control by Sturdevant.(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 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 Disease
References

67. PRESENTED BY :
DR.AKANKSHA SINGH
{PG 1ST YEAR}
PART 2

68.  STERILIZATION IN PERIODONTICS
 INFECTION CONTROL
 COVID IN DENTISTRY
 WASTE MANAGEMENT
 RECENT ADVANCES IN STERILIZATION AND DISINFECTION
 CONCLUSION
 REFERENCES

69. Sterilization in
periodontal clinic

70.  Sharp instruments are sterilized by aldehyde based sterilizer as they are heat
sensitive
SHARP
e.g. knives, scissors, Files Tissue holding forceps
BLUNT
Mouth mirrors,
tweezers,
artery forceps,
suture holding forceps,
Periosteal elevator

71. Sutures
• Sutures are pre sterilized by gamma radiation
• Sutures are re- sterilized by two recommended methods :
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

72. 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

73. 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

74. Effect of sterilization on instruments
sterilization Types of instruments
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(1981)

76. 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 patient
patient
operator
Other
personnel

77.  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.

80. 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)

81. Masks
Types:
1. Surgical masks (required to have
fluid-resistant properties).
2. 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.

82. Eye wear
CAUSES OF EYE DAMAGE:
• Aerosols and spatter may transmit infection
• Sharp debris projected from mouth while using air
turbine handpiece, ultrasonic scaler may cause
eye injury.
• Injuries to eyes of patients caused by sharp
instruments especially in supine position

83. Over garments
GOWN TYPE SITUATION AND RATIONALE
Cotton/linen, reusable or disposable, longsleeved
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)

84. 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

85. OCCUPATIONALLY ACQUIRED INFECTIONS
 HIV : 0.3% (0.1%-0.4%)
 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.

86. HIV Infection Control (OSHA)
ocupational safety and healthy administration
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
 Number of staff member to be kept minimum.

87.  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.

88.  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

89.  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

90.  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.

91.  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.

92. 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.

93. Prior to dental treatment
Before entering a dental office –
Delay non-urgent dental and cosmetic services.ADA,CDC
Prevent crowding in appointment setting by booking
appointments.ADA
Dental procedures in patients with a history of COVID-19 should
be postponed for at least 1 month.WHO

94. Use telephone triage, teleconferencing, or Teledentistry options as
alternatives to in-office care, if possible.CDC
High-risk patients like diabetic and immunocompromised patients
are treated at the early hours of a dental office opening.NHS
Ask staff to stay home if they are sick.CDC,ADA
Actively screen and record the temperature of each staff.Send staff
home if they develop symptoms while at work.CDC,NHS

95. At dental office
 Actively screen the patient at the time of check-in. Patients with fever should
refer to specific medical centers..CDC
 No accompanying individuals should be allowed.
 Offer hand wash or hydroalcoholic solutions (with 60–75% alcohol) for hand
disinfection upon entrance to the dental office.NHS,ADA
 Provide a large room with adequate ventilation in the waiting area.NHS
 Appropriate zoning and separation measures should be undertaken. Waiting
rooms and reception areas should allow for 2-m separation, ideally marked on
chairs and flooring.NHS

96.  Require the use of facemasks or cloth face coverings by everyone entering the
dental office.CDC
 Dental professionals should implement PPE (isolated wearing like N-95 masks,
Health or FFP2-standard masks, gloves, face shields, goggles, gown, surgical cap,
shoe cover).CDC
 Preparation of materials and instruments in advance and cover surfaces with
disposable protections.NHS
 Materials stored in a refrigerator should be sterilized before and after each
treatment.WHO
 Patients should be treated in an isolated and well-ventilated room with negative
pressure relative to the surrounding area.CDC

97. During dental treatment
 Hand hygiene should be performed before and after all patient contact,
contact with potentially infectious material, and before putting on and after
removing PPE. CDC
 Use alcohol-based hand rub (ABHR) with 60–75% alcohol. If hands are
visibly soiled, use soap and water for at least 20 s before returning to
ABHR.ADA
 Preoperative antimicrobial mouth rinse like peroxide could reduce the
number of microbes in the oral cavity. Since SARS-CoV-2 may be
vulnerable to oxidation, use 1.5% hydrogen peroxide or 0.2% povidone as
a preprocedural mouth rinse. ADA

98.  Rubber dams and high-volume saliva ejectors can help minimize
aerosol or spatter in dental procedures.ADA
 use extraoral dental radiographs, such as panoramic radiographs or
cone-beam C.T., as appropriate alternatives of intraoral radiography
 If aerosol-generating procedures are inevitable for emergency care, use
4-handed dentistry.CDC
 Avoid the use of aerosol-generating procedures, handpieces/ultrasonic
instruments, 3-in-1 syringes, and the air-water syringe whenever
possible.ADA,CDC

99. Waste management
Divided into two categories :
A)Bio-hazardous materials.
B) 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.

100. B) Non-bio-hazardous materials consist of waste materials : –
1. Matrix bands.
2. Masks, caps, gloves, patient’s napkin’s.
3. Impression materials.
4. X- ray packets & surface covers.

101. Categories of bio-medical waste in india
options Waste catergory
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,scalpels…)
Category 5 Discarded medicine and
cytotoxic drugs

102. 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

103. Color codes

104. 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

105. 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

106. 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.

107. 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 (orthophthalaldehyde)
 An antimicrobial drug that can be applied to animate and inanimate objects
(superoxidized water)

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.

111. • Texbook of microbiology by Prof. CP Baveja.(3rd edition)
• Ananthnarayan and paniker’s textbook (7th 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 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 Disease
References

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.
• Banaker et.al BMC oral health