detail explanation about infection control in dental clinic , personal protective barrier technique and sterilization and disinfection

1. Dr. Akash Ardeshana
1st year MDS
(Department of paedodontics and preventive dentistry)
1

2. content
Introduction
Objective
Infection and infection control
Infectious disease in concern in dental practice
Cross Infection
Transmission of infection in dental clinic
2

3. General principle of infection control
Needle stick injury and management
Conclusion
Bibliography
3

4. introduction
The concept of asepsis and it role in the prevention
of infection control was put forward nearly two
century ago.
1850- general principle laid down by lgnaz
semmelweiss in europe and oliver holmes in USA.
Principle were accepted after Joseph lister’s studies
on prevention of wound infection from 1865 to
1891.
4

5. Infection control procedure, although well recognized
in general medicine and surgery, were late in coming
to dentistry.
Several factors changed the perception of infection
control in dental profession, first was that blood and
saliva could be vectors for viral infection.
Second was AIDS pandemic.
5

6. Objective
Elimination or reduction in spread of infection from
all types of microorganisms.
Breaking the cycle of infection and eliminating cross
contamination.
The clinician has a professional responsibility for
implementing effective infection control to protect
other patients, and a responsibility for safe practice for
all members of the dental team.
Ensuring and showing to patients that they are well
protected from risks of infectious disease.
6

7. Infection
Infection is deposition of organisms in the tissues
and their growth resulting in host reaction.
The number of organisms required to cause an
infection is termed as the infective dose:
Depend on: virulence of the organism
susceptibility of host
age, pre existing dose and drug
7

8. Infection control
Prevention of spread of microorganisms from their
hosts
Kills or removal of microorganisms from obejcts and
surface.
8

9. Infectious disease in concern in
dental practice
Viral infection
Bacterial infection
Fungal infection
Parasitic infection
9

10. Microorganism Major transmission
route
N. Gonorrhoeae Inhalation
T. Pallidum Inhalation
M. Tuberculosis Inhalation/inoculation
Strep. pyogenes Inhalation
Bacteria
10

11. microorganism Major transmission root
CMV Inhalation
Hepatitis virus Inoculation
HSV 1 and 2 Inoculation
HIV Inoculation
Measles virus Inhalation
Mumps virus Inhalation
Influenza virus Inhalation
Rubella virus Inhalation
adenovirus Inhalation
viruses
11

12. Fungal infection: candidiasis
Parasitic infection: pneumocystis carinii infection
12

13. Tuberculosis
Transmitted by inhalation, ingestion and inoculation.
Two main infection:
tuberculous cervical lymphadenenitis
pulmonary infection
Prevention:
Immunization with BCG vaccine,
Gloves and mask should be worn,
The inhalation, sedation and anaesthesia equipment
must always be treated with high-level disinfectants .
13

14. Herpes simplex virus
This is most common herpese virus
transmitted to dental clinic staff.
Transmission of infection to dental
staff can result in primary herpetic
stomatitis or herpetic whitlow
Transmission occur by direct contact
of abraded skin or intact mucosa
with infected lesion or secretion .
14

15. Hepatitis B virus
DNA virus.
Incubation period 45 to 180 days.
HbsAg main indicator for active infection.
the mode of transmission: direct contact with infected
blood.
Prevention: all members of dental team should be
vaccinated against hepatitis and maintained this
vaccination schedule.
15

16. Hepatitis C virus
It is a RNA virus.
Blood born transmission.
The acute phase of HCV infection is usually
asymptomatic and only approximately 10% individuals
have overt hepatitis.
16

17. HIV
Inability to survive outside host organism.
Acts similar to STDs’
Looses its infectivity once desiccated.
Transmission:
Direct contact between infected host and
mucosal surface or epithelial wound.
Small amount of virus present in saliva.
Person cannot get infected by saliva alone
17

18. 18

19. Cross Infection
Cross-infection is defined as the transmission of
infectious agents among patients and staff within a
clinical environment.
patient practitionar
patient
19

20. Transmission of infection in dental
clinic
Factors affecting infection transmission
Source of infection
Means of infection
Route of transmission
Susceptible host
20

21. Modes of disease transmission
Personal contact
Carrier contact
Droplet transmission
Indirect transmission
21

22. Risk of transmission during dental treatment
Risk of transmission of through saliva
Transmission from dental personal to patient
Infection control in dental practice s revised edition 2006
s.Anil, Georges kryier
22

23. Categories of task in relation to risk
Category I:
Tasks that involved exposure to blood, body fluid or
tissues.
Category II:
Tasks that do not involve routine exposure to blood,
body fluids or tissues.
Category III:
Tasks that involve no exposure to blood, body fluids or
tissues.
23

24. So The American Dental Association (ADA) and
Occupational Safety and Health Act (OSHA)
guidelines advise that all dental office staff in category
I and II and dentists be trained in infection control to
protect themselves and their patient.
Essential of preventive and community dentistry 4th edition soben peter
24

25. OSHA rules on blood borne
pathogens
1. Establish an exposure control plan
2. Employers must update the plan annually
3. Implement the use of universal precautions
4. Identify and use engineering controls
5. Identify and ensure the use of work practice
controls
25

26. 7. Provide personal protective equipment (PPE), such as
gloves, gowns, eye protection, and
8. Make available hepatitis B vaccinations to all
workers with occupational exposure
9. Make available post-exposure evaluation and follow-
up to any occupationally exposed worker.
10. Use labels and signs to communicate hazards
11. Maintain worker medical and training records
Occupational safety and health
administration: blood born pathogen 26

27. GENERAL PRINCIPLE OF INFECTION
CONTROL
Identifying high risk patients and source of infection.
Universal protection
Prevent environmental contamination
Use of sharp instruments and needles
Handling biopsy specimen
Prosthodontic consideration
Infection control during radiography
Biomedical waste
others
27

28. Identifying high risk patients and
source of infection
Understaning the disease and their root of
transmission that has high susceptibility.
Using the CDC recommended question for taking a
medical history.
Screening every new patient by taking proper medical
history and oral examination.
Continuing to update patients’s medical history.
28

29. Universal protection:
All infected patient cannot identified on the basis of
medical history, physical examination and laboratory
examination.
Hence, the philosophy is that to consider all patients to
be infected with pathogenic organisms.
Hence it recommended that certain basis infection
control procedure must be followed routinely for all
patients, referred to as Universal Protection
29

30. Universal protections for dental team, include:
Routine hand washing
Protective barrier technique
Immunization
30

31. Hand washing is the key to
Control of Infection
31

32. Hitsorical background
32

33. Ignaz Philipp Semmelweis (1818-65)
Hungarian obstetrician educated
at the universities of Pest and
Vienna, introduced antiseptic
prophylaxis into medicine.
In the 1840s, puerperal or
childbirth fever, a bacterial
infection of the female genital
tract after childbirth, was taking
the lives of up to 30% of women
who gave birth in hospitals.
Women who gave birth at home
remained relatively unaffected.
33

34. Semmelweis observed that women examined by
student doctors who had not washed their hands after
leaving the autopsy room had very high death rates.
He also noted that the lesions of his friend’s wound were
similar to those found at post-mortem on those who had
died of puerperal fever.
Semmelweis concluded that puerperal fever was septic and
contagious.
34

35. He ordered students to wash their hands with
chlorinated lime before examining patients; as a result,
the maternal death rate was reduced from 12% to 1% in
2 years.
Nevertheless, Semmelweis encountered strong
opposition from hospital officials and left Vienna in
1850 form the University of Pest.
EID Journel Volume 7, Number 2—April 2001
Author affiliation: Centers for Disease Control and Prevention, Atlanta GA, USA
35

36. Routine hand washing
Proper handwashing, hand antisepsis, or surgical hand
antisepsis are simple acts that help reduce the risk of
disease transmission.
Transient microorganisms can come to rest on the
hands following direct contact with patients or
contaminated environmental surfaces.
36

37. These microorganisms, which colonize the top layers
of the skin, are most frequently associated with
healthcare-acquired infections.
Fortunately they generally can be removed with
routine handwashing.
37

38. Indications for hand hygiene include:
when hands are visibly soiled.
after barehanded touching of inanimate.
objects likely to be contaminated by blood,
saliva, or respiratory secretions.
before and after treating each patient.
before donning gloves and
immediately after removing gloves.
38

39. Before Decontaminating Hands
Cuts and Abrasions must be covered with a waterproof
dressing
Remove all jewellery and watches.
Fingernails should be kept short and
clean.
Nail art and nail varnish should not be worn.
Roll up your sleeves
39

40. What to Wash your Hands with.
 Hands which are visibly soiled or potentially grossly
contaminated.
 Liquid soap and water
 Dried thoroughly with a good quality paper towel.
 Hands which are contaminated.
 Alcohol hand gel.
Guidelines for Infection Control in Dental Health Care Settings
Sharon K. Dickinson, CDA, CDPMA, RDA; Richard D. Bebermeyer, DDS, MBA
40

41. Alcohol Hand rubs
 Quick, easy and convenient method to rapidly disinfect
physically clean hands.
 Decontaminate hands where hand-washing facilities do
not exist or are inappropriate.
 The disinfectant used is alcohol also include a
moisturiser.
41

42. Hand Hygiene
HANDWASHING IS THE SINGLE MOST IMPORTANT
MEASURE FOR PREVENTING INFECTION.
Less frequently missed
Least frequently missed
Most frequently missed
42

43. 43

44. Sequence for Donning PPE
gown
mask
Goggles or face
shield
glove
s
44

45. Protective Clothing- gown
Protective garments are worn over street clothes
to protect them from contamination.
Wear protective clothing that covers persona
wear long sleeved gown
Gowns are to be changed between every patient.
45

46. Protective clothing can
include:
reusable or disposable
gown, laboratory coat, or
uniform.
Material may be natural or
man made.
Clean or starile.
46

47. How to put a Gown?
first select the appropriate
type for the task and the
right size for you.
. The opening of the gown
should be in the back.
secure the gown at the neck
and waist
47

48. Mask:
The provide protection to nose
and mouth from likely splashes
and sprays of blood or body
fluids.
Splashes and spray can be
generated from a client’s behavior
(e.g. coughing or sneezing) or
during procedures (e.g.
suctioning, irrigation or cleaning
equipment).
48

49. Place over nose , mouth and chin .
Fit flexible nose piece over nose bridge
Secure on head with ties or elastic
Adjust to fit.
49

50. Gloves:
For protection of personnel and
patients in dental care setting ,
medical gloves always must be
worn by dental health care
workers when there is potential for
contacting blood, blood
contaminated saliva, or mucous
membrane.
50

51. Gloves
Purpose – patient care, environmental services,
other
Glove material – vinyl, latex, nitrile, other
Sterile or non-sterile
One or two pair
Single use or reusable
51

52. The American Dental Association has condemned the
reuse of gloves, because this practice results in defect
in the glove material, which will diminished its value
as an effective barrier, and adequate removal of
previous patient pathogen cannot be uniformly
guaranteed.
52

53. Do’s and Don’ts of Glove Use
Wear patient-care gloves when a potential exists for
contacting blood, saliva, other potentially infectious
materials, or mucous membranes.
Wear a new pair of patient-care gloves for each patient.
Ensure that appropriate gloves in the correct sizes are
readily accessible
53

54. Do’s and Don’ts of Glove Use
(cont’d)
Change gloves
During use if torn and when heavily soiled (even during
use on the same patient)
After use on each patient
Discard in appropriate receptacle
Never wash or reuse disposable glove.
54

55. 55

56. Protective eyewear
In dentistry two type
of product generally
available goggles or
eye shields and face
shields
56

57. How to Don Eye and Face
Protection
Position goggles over
eyes and secure to the
head using the ear
pieces or headband.
Position of face shield
over the face and secure
on brow with handle
band adjust to fit
comfortably
57

58. Sequence for removing PPE
gown
mask
Goggles or face
shield
gloves
58

59. How to Remove Gloves (1)
Using one gloved hand, grasp the
outside of the opposite glove near
the wrist.
Pull and peel the glove away from
the hand.
59

60. How to Remove Gloves (2)Slide one or two fingers of the
ungloved hand under the
wrist of the remaining glove.
Peel glove off from the
inside, creating a bag for both
gloves.
Discard in waste container.
60

61. Remove Goggles or Face Shield
Using ungloved hands,
grasp the “clean” ear or
head pieces and lift
away from face.
If reusable, place them
in a designated
receptacle for
subsequent
reprocessing.
Otherwise, discard.
61

62. Removing Isolation Gown
Unfasten ties.
Peel gown away from neck and
shoulder.
Turn contaminated outside toward
the inside.
Fold or roll into a bundle.
Discard.
62

63. Removing a Mask
Untie the bottom, then top,
tie
Remove from face
Discard
PPE Use in Healthcare Settings
63

64. Immunization procedure
The dental health care workers
are at a greater risk than the
general population, of
acuquiring hepatitis B and
AIDS through contact with
patient.
64

65. Immunization procedure available
to dental health care workers.
65

66. Serum hepatitis vaccine
Recombivax (by merck) and Engerix-B (Smithklin
Beecham) for hepatitis B are used.
Vaccine is given in three separte doses.
2nd dose is given after month of first dose and third
dose is given after six month of first dose.
The vaccine offers immunity for at least 7 years.
However some authorities in the uk have suggested
that a booster dose may be required after 5-7 years.
Infection control in dental practice s revised edition 2006
s.Anil, Georges kryier 66

67. Prevent environmental
contamination
All procedures and
manipulation of potentially
infective materials should be
performed carefully to
minimize droplates, splatters
and aerosols
67

68. Use of sharp instruments and
needlesAll sharp instrument should be
disposed of in designated puncture-
resistant containers.
Orthodontics wire and bands also
considered sharps, and disposed off
accordingly.
Unsheathed needles should not
remain on the instrument tray or in
operating.
68

69. 69

70. Clinical operating area
Special designated plastic are
used to cover the chair and
unit
Changes the bag after each
patient
70

71. Handling biopsy specimens
Should put in sturdy containers with with sacure lid to
prevent leaking during transportation.
71

72. prosthodontic
Dentist or dental assistant
prepares a potentially
infectious impression for by
rinsing the impression and
placing it in a biohazard
labeled plastic bag without
contaminating the bag’s
outer surface.
72

73. Dental radiograph
The staff working in radiology department usually, is
not aware of the medical history .
Hence ,it is essential to take certain precaution
73

74. Waste disposal in health care
settingWho classification of waste is
follows:
General nonhazardous
Sharps
Chemical and
pharmaceutical
Infectious
Other hazardous medical
wastes.
74

75. Aims of Waste Treatment:
Disinfection
Reduction in the bulk volume
Making surgical waste unrecognizable
Rendition of the dangerous recyclable itams unusable
75

76. 76

77. 77

78. Other precaution
Use of antimicrobial mouth rinse.
Rubber dam isolation
Minimizing dental aerosols and splatter
Minimize biofilm formation in water line.
78

79. Needle stick injuryMeasure for prevention:
Ensuring that the needle is
covered, when not in use.
Keeping full control and
concentration while handling.
Used needle should never be
recapped utilizing both hand.
79

80. An uncapped needle or syringe should not be passed
from assistant to surgeon.
Needle should not be purposely bent or broken by
hand.
Needle can safely re-capped by help of forceps to grasp
the cap.
80

81. Risk of HBV, HCV and HIV Transmission after
Occupational Per-cutaneous Exposure
HBV risk varies depending on e-antigen status of
source person
– If e-antigen positive, risk is up to 30%
– If e-antigen negative, risk is 1-6%
• HCV risk is 1.8%
• HIV risk is 0.3%
Elise M. BELtrami Risk and Management of Blood-Borne Infections in
Health Care Workers
Clin Microbiol Rev. Jul 2000; 13(3): 385–407. 81

82. Post-accidental management:
Remove the gloves
Wash the site with running water and soap
Inform the patient about the incident
To take blood specimens of both
82

83. If the patient is known or suspected HBV carrier.
prophylactic
Clinician never had vaccination
HBIG withi 48 hr.
Course of HB vaccination
Clinician have been vaccinated
If Ab titre is more then
100 IU/L
Within the previous yr.
No further action
Low Ab titer Booster dose
83

84. Presently, there is no prophylaxis
for HCV.
Monitoring the liver function and
testing for anti-HCV antibody.
May respond favourably, is treated
at the earliest sign of infection with
IF-a
84

85. In case ,the patient is seropsitive, has
AIDS or refuses the test.
Evaluated clinically and
serologically.
Advice to report if any febrile illness
that may occur within 12 week.
The HIV test should then be
repeated approximately 6 to 12
weeks after contamination and on a
periodic basis if seronegative .
85

86. Type Drugs regimen
Basic (28 days) Zidovudine +
lamivudine
600 mg/day (300 mg bid, 200
mg or 100 mg 4 hourly) + 150
mg
Expanded (28 days) As above +
indinavire or
Nelfinavir or
neviriapine
800 mg 8hourly, 750 mg tid, or
200 mg bid
HIV post exposure chemoprophylaxis for health worker
Textbook of oral and maxillofacial surgery second edition by NEElima Anil
Malik 86

87. Title Occupationally Acquired Human Immunodeficiency Virus (HIV)
Infection: National Case Surveillance Data During 20 Years of the HIV
Epidemic in the United States
Author Ann N. Do , MD; Carol A. Ciesielski , MD; Russ P. Metler , JD, MSPH; Teresa
A. Hammett , MPH; Jianmin Li , DPE, MEd; Patricia L. Fleming , PhD
Journal Infection Control and Hospital Epidemiolog Vol. 24, No. 2 (February
2003) (pp. 86-96).
Level of
evidence
III
Objectives: To characterize occupationally acquired human immunodeficiency virus
(HIV) infection detected through case surveillance efforts in the United
States.
Materials
and
Methods
Review of data reported through December 2001 in the HIV/AIDS Reporting
System and the National Surveillance for Occupationally Acquired HIV
Infection.
87

88. Result Of 57 healthcare workers with occupationally acquired HIV
infection, most (86%) were exposed to blood, and most (88%) had
percutaneous injuries. The circumstances varied among 51
percutaneous injuries, with the largest proportion (41%) occurring
after a procedure, 35% occurring during a procedure, and 20%
occurring during disposal of sharp objects. Unexpected
circumstances difficult to anticipate during or after procedures
accounted for 20% of all injuries. Of 55 known source patients, most
(69%) had acquired immunodeficiency syndrome (AIDS) at the time
of occupational exposure, but some (11%) had asymptomatic HIV
infection. Eight (14%) of the healthcare workers were infected
despite receiving postexposure prophylaxis (PEP). .
conclusion Prevention strategies for occupationally acquired HIV infection should
continue to emphasize avoiding blood exposures. Healthcare workers
should be educated about both the benefits and the limitations of PEP,
which does not always prevent HIV infection following an exposure.
Technologic advances (eg, safety‐engineered devices) may further
enhance safety in the healthcare workplace.
88

89. Conclusion
The most of postoperative infections result from the
faulty surgical technique, inadequate asepsis and
disinfection.
The success of prevention and control of infection in
healthcare areas is largely dependent on the aseptic
technique of all personnel, who perform the invasive
procedures, the sterility of all items directly concerned
in such procedure and the disinfection of all surface.
89

90. Bibliography
1. Infection control in dental practice s revised edition
2006 S.Anil, Georges kryier
2. Textbook of oral and maxillofacial surgery second
edition by Neelima Anil Malik
3. EID Journel Volume 7, Number 2—April 2001
Author affiliation: Centers for Disease Control and
Prevention, Atlanta GA, USA
4. Essential of preventive and community dentistry 4th
edition soben peter
5. Occupational safety and health administration:
blood born pathogen
90

91. 6. Guidelines for Infection Control in Dental Health
Care Settings , Sharon K. Dickinson, CDA, CDPMA,
RDA; Richard D. Bebermeyer, DDS, MBA
7. Text book of pediatric dentistry third edition Nikhil
Marwah
8. Journal ofInfection Control and Hospital
Epidemiolog Vol. 24, No. 2 (February 2003) (pp. 86-
96).Ann N. Do , MD; Carol A. Ciesielski , MD; Russ P.
Metler , JD, MSPH; Teresa A. Hammett , MPH; Jianmin
Li , DPE, MEd; Patricia L. Fleming , PhD 91

92. Thank you
92

93. Dr. Akash Ardeshana
1st MDS
Paedodontics and preventive dentistry
93

94. • application of standard precautions rather than universal
precautions;
• work restrictions for health-care personnel (HCP) infected with
or occupationally exposed to infectious diseases;
• management of occupational exposures to bloodborne
pathogens, including postexposure prophylaxis.
• Selection and use of devices with features designed to prevent
sharps injury;
• hand-hygiene products and surgical hand antisepsis;
• contact dermatitis and latex hypersensitivity;
• sterilization of unwrapped instruments;
CDC Guidelines for Infection Control in
Dental Health-Care Settings --- 2003
94

95. • dental water-quality concerns
• dental radiology;
• aseptic technique for parenteral medications;
• preprocedural mouth rinsing for patients;
• oral surgical procedures;
• laser/electrosurgery plumes;
• tuberculosis (TB);
• Creutzfeldt-Jakob disease (CJD) and other prion-related
diseases;
• infection-control program evaluation; and
• research considerations.
95

96. contents
Introduction and history
Definition of various terminology
A rational approach to disinfection and sterilization
Changes in Disinfection and Sterilization
Principles of sterilization
Factors that affect the efficacy of disinfection and
sterilization
96

97. Method of sterilization
Sterilization control
Operation room procedure.
Decontamination cycle
Conclusion
bibliography
97

98. introduction
Microorganism are ubiquitous .
Since they cause contamination, infection and decay, it
becomes necessary to remove or destroy them from
material or from areas.
The process of sterilization is used to prevent
contamination by extraneous organisms.
The method of sterilization employed depend on the
purpose for which it is carried out
98

99. B
A
C
K
G
R
O
U
N
D 99

100. Definition of various terminology
Sterilization: Sterilization describes a process that
destroys or eliminates all forms of microbial life and is
carried out in health-care facilities by physical or
chemical methods .
Disinfection: Disinfection describes a process that
eliminates many or all pathogenic microorganisms,
except bacterial spores, on inanimate objects
100

101. Cleaning: Cleaning is the removal of visible soil (e.g.,
organic and inorganic material) from objects .
Asepsis is the state of being free from disease-causing
contaminants (such as bacteria, viruses, fungi, and
parasites) or, preventing contact with microorganisms.
Guideline for Disinfection and Sterilization in
Healthcare Facilities, 2008
William A. Rutala, Ph.D., M.P.H.1,2, David J. Weber, M.D.,
M.P.H.1,2, 101

102. A RATIONAL APPROACH TO
DISINFECTION AND STERILIZATION
More than 30 years ago, Earle H. Spaulding devised a
rational approach to disinfection and sterilization of
patient-care items and equipment.
This classification scheme is so clear and logical that it has
been retained, refined, and successfully used by infection
control professionals and others when planning methods
for disinfection or sterilization.
Spaulding believed the nature of disinfection could be
understood readily if instruments and items for patient
care were categorized as critical, semicritical, and
noncritical according to the degree of risk for infection
involved in use of the items.
102

103. Critical Items
Critical items confer a high risk for infection if they are
contaminated with any microorganism.
This category includes surgical instruments, scaling
instruments, surgical burs, implants.
sterilized with steam if possible.
Heat-sensitive objects can be treated with EtO,
hydrogen peroxide gas plasma.
if other methods are unsuitable, sterilized by liquid
chemical sterilants.
103

104. Semi-critical Items
Sem-icritical items contact mucous membranes or
nonintact skin .
E.g Mirrors, Plastic instruments, amalgam condensers
Semicritical items minimally require high-level
disinfection using chemical disinfectant .
104

105. Noncritical Items
Noncritical items are those that come in contact with
intact skin but not mucous membranes.
E.g. , blood pressure cuffs, , stethoscope .
105

106. Changes in Disinfection and
Sterilization Since 1981
First, formaldehyde-alcohol has been deleted as a
recommended chemical sterilant or high-level disinfectant
.
Second, several new chemical sterilants have been added,
including hydrogen peroxide, peracetic acid, peracetic acid
and hydrogen peroxide in combination.
Third, 3% phenolics and iodophors have been deleted as
high-level disinfectants.
106

107. Fourth, isopropyl alcohol and ethyl alcohol have been
excluded as high-level disinfectants .
Fifth, a 1:16 dilution of 2.0% glutaraldehyde-7.05% phenol-
1.20% sodium phenate has been deleted as a high-level
disinfectant.
Sixth, the exposure time required to achieve high-level
disinfection has been changed from 10-30 minutes to 12
minutes or more .
Guideline for Disinfection and Sterilization in Healthcare Facilities, 2008
William A. Rutala, Ph.D., M.P.H.1,2, David J. Weber, M.D., M.P.H.1,2, 107

108. Principles of sterilization
All used instrument should thoroughly cleaned.
The sterilizing agent to be contact with every surface
of each item.
All sterilizing equipment must be regularly serviced
and maintained.
Follow the manufacturer’s instruction.
108

109. Factors that affect the efficacy of
disinfection and sterilization
Types of organisms
Number of organisms
Concentration of disinfecting agent
Presence of organic material (e.g., serum, blood)
Nature (composition) of surface to be disinfected
Contact time
Temperature
pH
Biofilms
109

110. Russell AD. Bacterial resistance to disinfectants: present knowledge and
future problems. J. Hosp. Infect. 1998;43:S57-68.
110

111. Number of organisms
Microbial load-the total number of organisms
which determine the exposure time of killing
agent
not all organisms die at the same time
higher numbers of organisms require longer exposure
111

112. Concentration of disinfecting agent
a proper concentration of disinfecting agents ensure
the activation of target organisms, e.g.,
povidone-iodine should be dilluted with water before
use because there is not enough free iodine to kill
microorganisms in concentrated solution
112

113. Presence of organic material
(such as blood, mucus, pus)
affects killing activity by inactivating the disinfecting
agent, e.g,
by coating the surface to be treated, prevents full contact
between object and agent (Glutaraldehyde)
easily inactivate bleach (Sodium hypochlorite)
For optimal killing activity, instruments and surfaces
should be cleansed of excess organic material before
disinfection !!!
113

114. Nature (composition) of surface to be disinfected
some medical instruments are manufactured of
biomaterials that exclude the use of certain
disinfection and sterlization methods because of
possible damage, e.g.,
endoscopic instruments cannot be sterilized by the
heat in an autoclave
114

115. Contact time
the amount of time a disinfectant or sterilant is in
contact with the object is critical!e.g.,
Betadine(alcohol and iodine) must be in contact
with object for at least 1 to 2 min.to kill microorg.
the spores of bacteria and fungi need a
muchlonger time
determine whether it is disinfecting or sterilizing the
object.
115

116. Temperature
Disinfectants are generally used at room temp.
(20C-22)
their activity is increased by an increased temp.
and decreased by a drop in temp
116

117. Biofilms
communities of microorganisms
can be on a surface of either inanimate or animate
objects, e.g.,
make disinfection more difficult
the concentration of the disinfectant and the
contact time need to be increased
117

118. pH
An increase in pH improves the antimicrobial activity
of some disinfectants (e.g., glutaraldehyde, quaternary
ammonium compounds) but decreases the
antimicrobial activity of others (e.g., phenols,
hypochlorites, and iodine).
The pH influences the antimicrobial activity by
altering the disinfectant molecule or the cell surface
118

119. method of
sterilization
Physical method
Chemical method
119

120. Physical methods
120

121. Sunlight
Appreciable bactericidal activity
Primary action due to ultraviolet rays
Semple and greg studied that typhoid bacilli
exposed to the sun on pieces of white cloth were
killed in 2 hours whereas in dark they were alive
after six days
121

122. Drying
Moisture is esssential for growth of bacteria
Drying in air has deletorius effect on some
bacteria
Unreliable method
Spores are unaffected
122

123. Heat
Most reliable method
Method of choice unless contraindicated
Factors influencing heat sterilization :
1. Nature of heat (Dry / Moist)
2. Temperature and time
3. Number of microorganisms
4. Characteristics of microorganisms
5. Type of material to be sterilize
123

124. Principles of different heat sterilizations
Dry Heat Moist Heat
Protein
denaturation,
oxidative damage
and toxic effect of
elevated levels of
electrolytes
Denaturation and
coagulation of
protein
124

125. Dry heat sterilization
It involves heating air with transfer of heat energy
from the air to the instrument.
Alternative method particularly ,the sharp instrument.
Advantage : the instrument do not rust, low cost
Disadvantage: time consuming and high temperature
require.
125

126. Hot air oven:
For laboratory glassware , glass syringe
and instrument.
Kelsey (1969) reported that the long
time require for sterilization , due to
poor conduction of air and poor
penetration by dry heat.
Custer and coyle (1970) found that
carbon steel instrument can loose their
hardness because of dry heat.
126

127. Relation of temperature and time.
C f TIME (MINUTE)
160 320 120
170 340 60
150 300 150
140 2050 180
127
Journal of American Dental Association Vol
122 December 1991

128. Spore testing should be done once a week to verify
proper functioning of the sterilization with the help of
bacillus atrophaeus strips.
128

129. Moist heat sterilization : autoclave
Steam sterilization involves heating water to generate
steam in closes chamber.
Known for destruction of all forms of microorganism
because
high penetrating capacity and give up a large amount
of latent heat.
129

130. Advantages
The results are consistently good, and reliable
The instrument can be wrapped prior to sterilization
Time efficient
Good penetration
Disadvantages:
Blunting and corrosion of sharp instrument
Damage to certain rubber goods
130

131. Principle of Autoclave
Large reduction in volume sucks inn more steam to the area
This process continues till the temperature
of that surface is raised to that of steam
Steam (Condensed water) under pressure
ensures killling of microbes present
Temperature at which water boils also increases
Saturated steam comes in contact with
cooler surface
Condenses to water and gives up latant heat
to that surface
When water boils when its vapour pressure is equal to surrounding atmosphere
Pressure inside closed vessel increases
131

132. Autoclave Temperature and Time Pressure Chart
Sterilizer temperature` Pressure time
Unwrapped
items
121 15psi 15 min
132 30psi 3 min
Lighty wrapped 132 30psi 8 min
Heavily wrapped 132 30psi 8 min
Journal of American Dental Association Vol 122 December 1991
132

133. The two basic types of steam sterilizers (autoclaves) are the
gravity displacement autoclave and the high-speed
prevacuum sterilizer.
133

134. 134

135. The gravity displacement autoclaves are primarily used to
process laboratory media, water, pharmaceutical products,
regulated medical waste, and nonporous articles whose
surfaces have direct steam contact.
The advantage of using a vacuum pump is that there is
nearly instantaneous steam penetration even into porous
loads.
The Bowie-Dick test is used to detect air leaks and
inadequate air removal
135

136. To avoid minimize corrosive action of steam on metals,
crawford and oldenburg (1967) recommended the
addition of ammonia to the autoclave.
Accepted dental therapeutics (1977) recommendeds
use of dicyclohyxylammonium nitrate or
cyclohexylamine and decylamine
Bertlotti and hurts (1978) recommended 2 percent
sodium nitrate.
136

137. Flash Sterilization
Overview. “Flash” steam sterilization was originally defined
by Underwood and Perkins as sterilization of an
unwrapped object at 132C for 3 minutes at 27-28 lbs. of
pressure in a gravity displacement sterilizer.
Flash sterilization is a modification of conventional steam
sterilization.
137

138. Uses. Flash sterilization is considered acceptable for
processing cleaned patient-care items that cannot be
packaged, sterilized, and stored before use
138

139. Glass beads sterilization:
This method employs a heat transfer device.
The temperature achieved is of 220*c.
Warm–up time of at least 20 minutes
The media used are glass beads, molten metal or salt
kept in a cup.
Use for small instrument like endodontic files, burs,
rotary instruments
Sterilization time 10 sec.
139

140. Oliet et al (1958) reported that
temperatures vary in different
areas of sterilization.
Grossman (1974) recommended
the use of salt media.
140

141. low-temperature sterilization
Ethylene oxide (ETO) (has been widely used as a low-
temperature sterilant since the 1950s .
Overview
ETO is a colorless gas that is flammable and
explosive.
parameters (operational ranges) are: gas concentration
(450 to 1200 mg/l); temperature (37 to 63oC); relative
humidity (40 to 80%)(water molecules carry ETO to
reactive sites); and exposure time (1 to 6 hours)
Association for the Advancement of Medical Instrumentation.
Ethylene oxide sterilization in health care facilities: Safety and
effectiveness. AAMI. Arlington, VA, 1999.
141

142. 142
Mode of Action.
The microbicidal activity of ETO is considered to be
the result of alkylation of protein, DNA, and RNA.
ETO inactivates all microorganisms although bacterial
spores (especially B. atrophaeus) are more resistant than
other microorganisms. For this reason B. atrophaeus is the
recommended biological indicator.
Uses.
ETO is used in healthcare facilities to sterilize critical
items (and sometimes semicritical items) that are
moisture or heat sensitive and cannot be sterilized by
steam sterilization.

143. Hydrogen Peroxide Gas Plasma
Overview. New sterilization technology based on
plasma was patented in 1987 and marketed in the
United States in 1993.
143

144. Mode of Action
This process inactivates microorganisms primarily by the
combined use of hydrogen peroxide gas and the generation
of free radicals (hydroxyl and hydroproxyl free radicals)
during the plasma phase of the cycle.
Uses :
Materials and devices that cannot tolerate high
temperatures and humidity, such as some plastics, electrical
devices, and corrosion-susceptible metal alloys, can be
sterilized by hydrogen peroxide gas plasma
144

145. Irradiation:
Ionizing radiation
Non ionizing radiation
145

146. Ionizindiation:
Include x-ray , gamma rays, and high speed electron.
It is effective for heat labile items.
Bellamy(1959) it has greater penetration properties.
The lethal action is due to effect on the DNA of
nucleus and on the other vital cell compound.
commonly used by industry to sterilize disposable
material.
146

147. Non-ionizing radiation
Ultraviolet Radiation (UV)
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.
Use: operating rooms, isolation
rooms, and biologic safety cabinets.
147

148. 148

149. Infrared:
Another form of dry heat sterilization
Most commonly use to purify air, such as in the
operating room
149

150. Boiling water
Boiling water produces a temperature of 100 c at
normal atmospheric pressure.
It require 10 minutes exposure to this temperature,
to kill many bacteria and some viruses.
However , prolonged time of 24 hr is require to kill
bacterial spores, and even this prolong time will
not kill many viruses.
150

151. STERILIZATION CONTROL
To ensure that potentially infectious agents are
destroyed by adequate sterilisation regimes
Three levels:
physical: measuring device control (temp., time,
pressure)
chemical: substances that undergo a colour change or
have melting points within the sterilizing range
-Browne's tubes, Bowie Dick tape
-give an immediate indication of a successful or non-
successful sterilization
151

152. Browne's tubes are glass tubes that contain heat
sensitive dyes. These change colour after
sufficient time at the desired temperature.
Before heat exposure, the contents of the tube appear
red.
As heating progresses, the colour changes to green.
Only when the tube is green sterilisation
conditions can be considered adequate.
www.surgicalnote.co.uk/node/210 152

153. Bowie Dick tapeis applied to articles being
autoclaved.
Before heat exposure, the tape is uniformly buff
in colour.
After adequate heating, the tape develops dark
brown stripes.
The pack on the left has been properly sterilised;
that on the right has not.
Chemical indicator
153

154. biological:
Bacillus stearothermophilus spores
survives steam heat at 121ºC for 5 min. and is killed at
121ºC in 13 min.
validate and determine the adequacy of steam or
chemical vapor sterilisation
Bacillus subtilisspores
validate and determine the adequacy of ethylene
oxide or dry heat sterilisation
154

155. 155
CHEMICAL DISINFECTION

156. Properties of an ideal disinfectant.
Broad spectrum: should have a wide antimicrobial spectrum
Fast acting: should produce a rapid kill
Not affected by environmental factors: should be active in the
presence of organic matter (e.g., blood, sputum, feces) and
compatible with soaps, detergents, and other chemicals
encountered in use
Nontoxic: should not be harmful to the user or patient
Surface compatibility: should not corrode instruments and
metallic surfaces and should not cause the deterioration of cloth,
rubber, plastics, and other materials
Residual effect on treated surfaces: should leave an antimicrobial
film on the treated surface
Easy to use with clear label directions .
156

157. Odorless: should have a pleasant odor or no odor to
facilitate its routine use
Economical: should not be prohibitively high in cost
Solubility: should be soluble in water
Stability: should be stable in concentrate and use-
dilution
Cleaner: should have good cleaning properties
Environmentally friendly: should not damage the
environment on disposal
157

158. alcohol
Overview.
two water-soluble chemical compounds—ethyl
alcohol and isopropyl alcohol
These alcohols are rapidly bactericidal rather than
bacteriostatic against vegetative forms of bacteria;
they also are tuberculocidal, fungicidal, and
virucidal but do not destroy bacterial spores.
Their cidal activity drops sharply when diluted
below 50% concentration, and the optimum
bactericidal concentration is 60%–90% solutions in
water. 158

159. Mode of Action
The most feasible explanation for the
antimicrobial action of alcohol is
denaturation of proteins.
Microbicidal activity:
Ethyl alcohol, at concentrations of 60%–
80%, is a potent virucidal agent.
Isopropyl alcohol (20%) is effective in
killing the cysts of Acanthamoeba
culbertsoni.
159

160. Phenols
Used as Disinfectant
Used by Joseph Lister in form
of carbolic acid
High concentration phenolic
compounds
Acts as a protoplasmic poisons
Precipitate Protein
Destroy cellwall
160

161. Lipophillic virus are susceptible
Spores are resistant
Two or more synthetic phenols in
combination
Action against hydrophilic viruses
Accepted by ADA for surface
disinfectant on precleaned
surfaces
161

162. Aldehydes
formaldehyde ( HCHO)the most imporatant is a water-
soluble gas -formalin (35% solution of this gas in water) or
glutaraldehyde (disinfectant and sterilizer!!!)
denaturat proteins and nucleic acids
irritate mucosa, skin contact may result inflamations or allergic
eczemas
broad-sepctrum: againts bacteria, fungi, and viruses
chemosterilizerin higher concetrations (sporicidial)
Application: -disinfectionof surfaces and objects (plastic
and rubber items)
sterilizerof choice for heat-sensitive medical equipment
162

163. A 2 percent glutaraldehyde (cidex)
require immersion of 20 minutes
for disinfection.
Stonehill et al (1963) reported that
cidex kills vegetative bacteria ,
spores, fungi and virus by
alkylation on a 10 hr contact.
163

164. Chloride compound:
Overview. Hypochlorites,
the most widely used of the
chlorine disinfectants, are
available as liquid (e.g.,
sodium hypochlorite) or
solid (e.g., calcium
hypochlorite). The most
prevalent chlorine
5.25%–6.15% sodium
hypochlorite is used.
164

165. They have a broad spectrum of
antimicrobial activity,
do not leave toxic residues,
unaffected by water hardness, a
inexpensive and fast acting,
remove dried or fixed organisms and
biofilms from surfaces.
165

166. Hydrogen peroxide:
Hydrogen peroxide works by producing destructive
hydroxyl free radicals that can attack membrane lipids,
DNA, and other essential cell components.
A 0.5% accelerated hydrogen peroxide demonstrated
bactericidal and virucidal activity in 1 minute and
mycobactericidal and fungicidal activity in 5 minutes .
Commercially available 3% hydrogen peroxide is a
stable and effective disinfectant
166

167. Iodophors
Iodine solutions or tinctures long have been used by
health professionals primarily as antiseptics on skin or
tissue .
Iodine can penetrate the cell wall of microorganisms
quickly, and the lethal effects are believed to result
from disruption of protein and nucleic acid structure
and synthesis.
iodophors are bactericidal, mycobactericidal, and
virucidal but can require prolonged contact times to
kill certain fungi and bacterial spores
167

168. Operating room procedure
Through cleaning of the floor.
Cleaning of the wall with hand compression sprayer.
168

169. Fumigation is initiated after setting up of instrument
(steri trax) in place
The chemical used is 40 % formalin for 30 minutes.
About 180 ml is used for a room of the size 1000 cubic
feet.
169

170. Parameters Optimal level
1 Relative humidity Over 70%
2 Temperature 30-40 C
3 Formaldehyde levels 5 ppm or more
Parameter and the optimum levels for effective fumigation
170

171. Masks
Eye protection
hair/bread cover
Footwear
Antiseptic enviroment
Hand scrub and hand disinfection
Preparation of surgical site
171

172. Decontamination cycle
172

173. Cleaning
Disinfection
Inspection
manual
ultrasonic
173

174. Packing
Sterilization
Storage
use
174

175. Recommended sterilization procedures for commonly used dental
instruments / equipments
175

176. 176Infection control in dental practice revised edition2006 S.anil Georges krygier

177. 177Infection control in dental practice revised edition2006 S.anil Georges krygier

178. Title Knowledge and attitude of general dentists of Ahwaz about disinfection of
dental impressions
Author Raju, T. B. V. G.1 Garapati, Satish2Agrawal, Rupika3Reddy, Sridhara4Razdan,
Ankur5 Kumar, S. Kishore6
Level of
evidence
journal Journal of International Oral Health. Nov/Dec2013, Vol. 5 Issue 6, p108-112. 5p. 4
Color Photographs, 1 Chart, 1 Graph.
aim Aim of the study was to compare 4 different methods of sterilizing endodontic
files in dental practice.
Methods and
material
The present study was performed on 100 K-files, 21 mm long and of size 25. Of
these, 20 files were taken as control group, and the remaining 80 files were
divided into 4 groups of 20 files each and they were tested for the efficacy of
sterilization with different methods: Autoclave, glass bead, glutaraldehyde and
CO2 laser
Results The study showed that the files sterilized by autoclave and lasers were completely
sterile. Those sterilized by glass bead were 90% sterile and those with
glutaraldehyde were 80% sterile
conclusion The study concluded that autoclave or laser could be used as a method of
sterilization in clinical practice and in advanced clinics; laser can be used also as
a chair side method of sterilization
178

179. Title Knowledge and attitude of general dentists of Ahwaz about disinfection of
dental impressions
Author Lavaf, Shirin
Azizi, Arash1 drarashazizi@yahoo.com
Shantia, Maryam
Level of
evidence
journal Journal of Isfahan Dental School. 2013, Vol. 8 Issue 7, p676-683. 8p.
aim The aim of this study was to evaluate the knowledge and attitudes of dentists
about disinfection of dental impressions
Methods and
material
In this descriptive study 93 general dentists were randomly selected in Ahvaz in
2010. To collect data, a questionnaire which included demographic data and 15
questions about knowledge and 14 questions about attitude was prepared.
Results The results of this study showed that the majority of dentists in Ahwaz have good
attitude toward disinfection and the related equipment but they have poor
knowledge about the use of disinfecting agents, necessitating continuous
educational programs in this respect
179

180. 180

181. 181

182. conclsion
When properly used, disinfection and sterilization can
ensure the safe use of invasive and non-invasive
medical devices. However, current disinfection and
sterilization guidelines must be strictly followed.
182

183. Guideline for Disinfection and Sterilization in
Healthcare Facilities, 2008 William A. Rutala,
Ph.D., M.P.H.1,2, David J. Weber, M.D., M.P.H.1,2,
183

184. 1. Guideline for Disinfection and Sterilization in
Healthcare Facilities, 2008 William A. Rutala, Ph.D.,
M.P.H.1,2, David J. Weber, M.D., M.P.H.1,2,
2. Infection control in dental practice revised edition2006
S.anil Georges krygier.
3. Text book of microbilogy 8th edition ananthnarayan
4. Text book of oral and maxillofacial surgery 2nd edition
Neelima MaliK
5. Text book of pediatric dentistry third edition Nekhil
Marwah.
184

185. 6. www.surgicalnote.co.uk/node/210
7. Association for the Advancement of Medical
Instrumentation. Ethylene oxide sterilization in
health care facilities: Safety and effectiveness. AAMI.
Arlington, VA, 1999.
8. Journal of American Dental Association Vol 122
December 1991
9. Russell AD. Bacterial resistance to disinfectants:
present knowledge and future problems. J. Hosp.
Infect. 1998;43:S57-68.
185

186. THANK YOU
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