INFECTION CONTROL IN A DENTAL PRACTICE

1. Dr. Rohit Bansal

3.  The recent upsurge in life threatening diseases-
HIV,HBV,HCV has forced dental practioners to give
emphasis to infection control.
 Dental health care workers, through occupational
exposure, may have a 10 times greater risk of
becoming a chronic hepatitis B carrier than the
average citizen.

5. Responsibility of infection control is that of
each student , faculty member , & staff
person involved in patient care & clinical
management

7.  STERILIZATION describes a process that
destroys or eliminates all forms of microbial
life including spores.
 DISINFECTION describes a process that
eliminates many or all pathogenic
microorganisms, except bacterial spores, on
inanimate objects.

8.  CLEANING is the removal of visible soil (e.g.,
organic and inorganic material) from objects and
surfaces and normally is accomplished manually or
mechanically using water with detergents or
enzymatic products.
Guideline for Disinfection and Sterilization in
Healthcare Facilities, 2008 Vol. 52 / RR-17

9.  An EXPOSURE can be defined as a percutaneous
injury (e.g., needlestick or cut with a sharp object)
or contact of mucous membrane or non-intact skin
(e.g., exposed skin that is chapped, abraded, or
with dermatitis) with blood, saliva, tissue, or other
body fluids that are potentially infectious.
Centers for Disease Control

11.  Protect patients and member of the dental team.
 Reduces and minimizes the concentration of
infectious microbes in oral environment.
 Break the cycle of infection to eliminate cross
infection.

13. A) Airborne contamination
B) Hand-to-surface contamination
C) Cross infection
D) Patient vulnerability
E) Personnel vulnerability

14.  A high speed handpiece is capable of creating
airborne contaminants in the form of aerosols,
mists and splatter.
 AEROSOLS are invisible particles ranging from 5-
50 microns which carry any respiratory pathogens
to the lungs.

15.  MISTS are droplets approaching 50microns. Both
aerosols and mists produced by cough of patient
with unrecognized active pulmonary or Pharyngeal
tuberculosis are likely to transmit the infection.
 SPLATTER are particles larger than 50 microns and
are visible which has a distinct trajectory i.e. usually
falls within 3 feet of patient mouth. Splatter has a
potential of causing infection of dental personnel by
blood borne pathogens.

16.  With saliva contaminated hands, the dentist
could repeatedly contact or handle unprotected
Operatory surfaces during treatment if not
careful.
 Amalgamators, light curing devices, camera
equipment are also subjected to heavy
contaminations by soiled hands.
 Contamination free maintenance
of these items is a priority
objective today.

17.  Cross infection can be defined as the
transmission of infectious agents between
patients and staff within a clinical environment.
 Transmission may result from person to person
contact or via contaminated objects.
 Transmission of infection from one person to
another requires a source of infection. The
infective agent is transmitted through blood,
droplets of saliva and instruments contaminated
with blood, saliva and tissue debris.

18.  Transmission of cross infection in Conservative
Dentistry and Endodontics may occur by direct
contact of tissue with secretions or blood, from
droplets containing infectious agent, or via
contaminated sharps or instruments which have
been improperly sterilized.

19.  Although infection risks for dental patients have
not been as well investigated as those of hospital
patients, they appear to be low.
 When dental personnel experience exposure of
saliva, blood, and possible injury from sharp
instrumentation while treating patients, they are
more vulnerable to infections if they have not had
proper immunizations or used the protective
barriers.

21. 1.Employer must provide HB immunization to employees
without charge within 10 days of employment
2.Universal precautions should be taken.
3.Must implement work control practice.
4.Provide facilities & instructions for washing hands.
5.Must prescribe safe handling of sharp items(Eg. one
handed technique).
6.Disposal of single use sharp items in puncture resistant
colored containers close to the place of use.
7.Use a basket/ cassette to place into & retrieve reusable
sharp instruments from soaking pans & ultrasonic
cleaners.
8.Prohibit eating & storage of eatables where blood &
infectious materials are present.
9.Place blood & contaminated specimens in suitable leak
proof closed containers.

22. 10.Employer must provide employees with necessary
Personnel Protective Equipment(PPE).
11.Ensure that employees correctly use & discard
PPE.
12.After Treatment attend to housekeeping
requirement.
13.Employer must provide written schedule for
cleaning & decontamination
14.Contaminated equipment must be
decontaminated before service
15.Employer must provide laundering of protective
garments used for universal precautions at no cost
to employees.
16.Must implement engineering control(

23. HOUSEKEEPING is a term that relates to cleanup of
treatment-soiled operatory equipments,
instruments, counters, and floors as well as
management of used gowns and wastes.
WORK PRACTICE CONTROLS AND ENGINEERING
CONTROLS are term used to describe precautions
(e.g., careful handling of sharp instruments, and
not putting hands into sharp containers) and use
of devices to reduce contamination risks (e.g.,
using high volume suction, rubber dam, and
protective sharp containers.

25.  Infection control procedures must be applied
for all patients, because all patients must be
considered potentially infectious.
 Identification of infectious patients is not
possible even by medical history which
cannot provide complete information for the
detection of all disease carrier states.
 Some patients may be unaware of infection or
past exposure to any infectious disease.

26. GLOVES:
 OSHA regulation specify that all clinical
personnel must wear treatment gloves during
treatment procedures.
 Gloves should not be washed, after each patient
new gloves should be worn.
 The value of gloves was emphasized by finding
that without gloves, occult blood persisted under
dentist’s fingernails for several days after patient
contact (J Am Dent Assoc 105:358-362 1982)
 Gloves also help to prevent very painful and
transmissible herpetic infections to fingers.

27.  FDA regulations says that less than 4% can have
leak detectable by water test.
 Viruses have been found to penetrate no more
than one intact latex glove out of 100.
 While cleaning and sorting sharp instruments
one should wear puncture-resistant utility
gloves.
 Nitrile latex gloves are preferred they can be
washed inside and out, disinfected as well as
autoclaved, as needed.

28. Remove gloves that
are cut, punctured
and torn.
Donot wash,disinfect
or Sterilize gloves for
reuse

29. How to wear the gloves correctly:
How to remove the gloves

31. MASKS
 When the susceptible person wears a mask most
of the contaminated droplets spreading onto the
person’s face from infected person are blocked .
 When an infected human coughs or sneezes,
particles of varying sizes ranging from large
particle droplets (about 100 µm in diameter) to
small particle droplets (about 0.1 µm in
diameter) are created.
 Masks have pore sizes from
0.3∼50 µm in diameter .

33.  Masks are not adequate to hold back measles,
influenza, and other aerosols.
 Masks with highest filtration are rectangular,
folded types used for surgeries.
 Dome shaped masks are adequate barriers
against spatter and are considered to prevent
HB and HIV infection.
 The mask should be between every patients or
whenever it becomes moist or visibly soiled.

34. HEADCAP:
 Hair should be properly tied and long hair should be
either covered or restrained from face. Hence, head cap
must be used.
PROTECTIVE EYEWEAR
 Clinicians, helping staff and patients must protect their
eyes against foreign bodies, splatter and aerosol
during operative procedures by using protective
glasses.
 Eyewear protects eyes from damages from instruments
and contamination from microbes such as Hepatitis B
virus, which can be transmitted via conjuctiva.

35. PROTECTIVE OVERGARMENT
 An over garment must be protective of clothing
and skin.
 Over garment must be changed whenever
becoming moist or visibly soiled.
 Laundering with regular cycle with regular
laundry detergent is considered acceptable,
following manufacturer’s direction
 Hot water up to 700 with 50 to
150 ppm chlorine can be used
to disinfect it.

36.  Hand should be washed for a period of 15 sec to
6 minutes.
 For routine treatment period watches, jewelry,
and rings should be removed, wash hand with
suitable cleanser. Lather hands for atleast 10 sec,
rubbing all surfaces, and rinse.
 Use a clean brush to scrub under and around
nails. When changing gloves, washing hand is
required.
 Hand cleansers containing a mild antiseptic like
3% PCMX (p-chloro, meta-xylenole) or
chlorhexidine are preferred to control transient
pathogens and to suppress overgrowth of skin
bacteria.

37. Indication of Hand Hygiene
 When hands are visibly contaminated.
 Before and after treating each patient (e.g., before
glove placement and after glove removal.
 After barehanded touching of inanimate objects
likely to be contaminated by blood or saliva.
 Before regloving after removing gloves that are
torn, cut, or punctured.
 Before leaving the dental operatory, dental
laboratory, or instrument processing area.

40.  Spaulding’s Classification(1968)

41.  CDC recommends that
1) Critical and Semi-critical instruments are to be
Heat sterilized.
2) Semi-Critical items are sensitive to heat
treatment and should be treated with High level
Disinfection after cleaning.
3) Non critical items can be treated intermediate to
low level disinfectant after cleaning.

42.  Use a designated processing area to control
quality and ensure safety
 Divide processing area into work areas
◦ Receiving, cleaning, and decontamination
◦ Preparation and packaging
◦ Sterilization
◦ Storage

45.  Sterilization provides a method of instrument
recycling that can be monitored and documented to
show that conditions for control of disease
transmission were indeed established.
 Most instruments contact mucosa or penetrate oral
tissues, it is essential that reused instruments be
thoroughly cleaned and sterilized by accepted method
that can be routinely tested and monitored.

46. PHYSICAL METHOD
 Sun Light
 Drying
 Heat
◦ Dry
◦ Moist
 Filtration
 Gas
 Irradiation
 Ultra sonic cleaning
 Oil

47. CHEMICAL METHOD
 Phenol Derivatives : Phenol, Cresol, resorcinol, chloroxylenol
 Oxidizing agents : Pot. Permanganate, Hydrogen Peroxide,
Benzoyol Peroxide
 Halogens : Iodine, chlorine
 Biguanide : Chlorhexidine
 Quarternary Ammonium (Cationic) : Cetrimide, Zephiran
 Soaps : of Sodium & Potassious
 Alcohols : Ethanol, Isopropanol.
 Aldehydes : Formaldehyde, Glutaraldehyde
 Acids : Boric acid, acetic acid
 Metallic salts ; Silver Nitrate, Zince Sulfate, Zinc Oxide,
calamine, Ammoniated mercury.
 Dyes : Gentian violet, proflamine, Acriflamine
 Furan derivatives : Nitro flurazone

48.  The four accepted method of sterilization are
1. Steam pressure sterilization (Autoclave)
2. Chemical vapor pressure sterilization (Chemiclave)
3. Dry heat sterilization (Dryclave)
4. Ethylene oxide sterilization.

49.  Sterilization with steam under pressure is performed
in a steam autoclave
 The time required at 1210 C is 15 mins at 15 lbs of
pressure.
 Time for wrapped instruments can be reduced to 7
mins if temperature is raised to approximately 134o C
at 30 lbs pressure.
 Advantages of Autoclave
1) Most rapid and effective
2) Most effective for sterilizing cloth, surgical
packs and towel packs.

50.  Types of Autoclaves
1) Gravitational Displacement Sterilizers
2) Steam Sterilizers with Pre- and Post- Vaccume
processes
 Disadvantages of Autoclave
1) Items sensitive to heat cannot be sterilized.
2) It tends to corrode carbon steel burs and
instruments.
3) Steam appears to corrode the steel neck and shank
portion of some diamond instruments and carbide
burs.

51.  Sterilization by chemical vapor under pressure is
performed in Chemiclave
 Chemical vapor pressure sterilizer operates at 2700
F(1310 C) and 20 pounds of pressure.
 They have a cycle time of half an hour.

52.  Advantages of Chemiclave
Carbon steel and other carbon sensitive burs,
instruments and pliers are sterilized without rust or
corrosion
 Disadvantage of Chemiclave
1)Items sensitive to elevated temperature will be
damaged
2) Instruments must be very lightly packed.
3) Towel and heavy clothing cannot be sterilized.

53. CONVENTIONAL DRY HEAT OVENS
 Dry heat sterilization can be readily achieved at
temperature above 1600 C.
 Conventional dry heat sterilizer have heated chambers
that allow air to circulate by gravity flow (gravity
convection).
 Packs of instruments should be kept 1 cm apart
 Foil wrap or special nylon bags are used.
 60-90 mins are required for sterilization of medium
load lightly wrapped instruments.

54.  Disadvantages
1) Without careful calibration, more sterilization
failures are obtained with gravity convections dry
heat ovens than any other type of sterilizer
2) The most accurate way to calibrate a sterilization
cycle is by using external temperature gauge
(pyrometer) attached to a thermocouple wire.

55. SHORT CYCLE, HIGH-TEMPERATURE DRY HEAT
OVENS
 A rapid high temperature process that uses a
forced-draft oven (a mechanical convection oven
that circulates air with fan or blower)
 It reduces total sterilization time to 6 mins for
unwrapped and 12 mins for wrapped instruments
 It operates at a temperature range of 370 to 3750
F.
 Advantages
Carbon steel and burs do not rust, corrode, or loose
their temper or cutting edges if they are well dried
before processing

56.  Disadvantages
1) Rubber or plastic goods can get damaged
2) Heavy loads of instruments and heavy wrapping
can cause failure.
3) Cycles are not automatically timed in some of the
sterlizers.

57.  It is the best method of sterilization of complex
instruments and delicate materials.
 Automatic devices sterilize items in several hours
and operate at elevated temperature well below
1000 C
 Less expensive device operates at room
temperature to sterilize overnight

58.  Advantages
Units with large chambers hold more instruments or
packs per cycle
 Disdvantages
Porous or plastic materials absorb the gas and require
aeration for 24 hours or more before it is safe for them
to contact skin or tissues.

59. Boiling Water
 Boiling water does not kill spores and cannot
sterilize instruments
 Incase of sterilizer breakdown only this method
should be followed
 Well cleaned items must be completely submerged
and allowed to boil at 1000 C for 10 mins
Ultraviolet light
 Used for sanitizing room air to help control TB
bacilli
 Not effective against RNA viruses such as HIV
 Not effective against bacterial spores
 Incomplete exposure of all surfaces & poor
penetration of oil & debris

60.  It is a rapid mode of sterilization which uses table
salt consisting of 1% Silico-aluminate, Sodium
Carbonate or Magnesium Carbonate.
 Salt can be replaced by Glass Beads provided that
the beads sizes < 1mm in diameter because larger
beads are not efficient enough due to the presence
of large spaces in between.
 The instrument is sterilized in 5-15s at a
temperature of 437-465°F even if inoculated with
spores.
 Disadvantage: Doesn’t completely sterilize the
instrument i.e. the handle.

61.  Sterilization not only protects patients from cross
infections, but also protects personnel from the
infection of previous patients as well.
 In dental offices, sterilization must be monitored
weekly with biologic spore tests using heat
resistant spores and tested daily with color change
process-indicator strips.
 STERILIZATION MONITORING HAS 4 COMPONENTS
1. Sterilization indicators and date
2. Process indicator strips
3. Biologic monitoring strips
4. Documentation notebook

62.  Sterilization indicators, both tapes and bags are marked
with heat sensitive dyes that change color easily upon
exposure to heat or sterilizer chemicals
 Process indicator strips provides an inexpensive,
qualitative, daily monitor of sterilizer function,
operation and heat penetration into packs
 Biologic monitoring strips consists of spores dried on
absorbent paper and are calibrated to be killed when
sterilization conditions are reached and maintained
for necessary time to kill all
pathogenic microorganisms.
( Bacillus stearothermophilus)

64.  It is a two step procedures
 1st step is vigorous scrubbing of the surfaces to
be disinfected and wiping them clean.
 2nd step wetting the surface with a disinfectant
and leaving it wet for the time prescribed by
the manufacturer.
 Preferred disinfectants are those that can
inactivate polio or Coxsackie's viruses because
they are non lipid viruses similar to HB virus in
resistance.

65.  Activity of disinfectants is reduced by organic debris. Iodine's
are specially sensitive to the presence of blood.
 Most water based disinfectants are effective for removing
dried blood
 Disinfectants containing 70-79% ethyl alcohol are considered
most effective disinfectants on cleaned surfaces (J Am Dent
Assoc 119:493-94 1989)
 Disinfection cannot occur unless fresh disinfectant is
reapplied to a thoroughly cleaned surface and disinfection
does not sterilize. ( Am J Epedemiol 116:828-833,1989)
 Most disinfectants, except plain phenol, appear to be active in
approximately 5 mins. Equipments should be left wet until
next patient is seated approximately 5 mins.

66. Low Level Disinfectant
 Ethanol and Isopropyl alcohols are commonly used
alcohols which have antibacterial activity but not effective
against viruses and spores.
 Cant be used for
1) Carbon steel instruments
2) Rubber instruments.
Intermediate level, Broad spectrum Disinfectant
 Phenol are used for this catogary of disinfection. But it
must be noted that these are toxic to living tissues.
 There spectrum includes Lipophillic viruses, Fungi and
Bacteria but no spores.
 Used for disinfection of inanimate objects such as walls,
floors, etc.

67. Liquid Sterilants And High Level Disinfectants
 Liquid sterilants are those that can kill bacterial spores in 6 to
10 hours.
 These sterilants are high level disinfectants and are EPA
registered
 E.g.. Glutaraldehydes at 2-3% concentrations.
 Glutaraldehydes are irritating, sensitizing to skin and
respiratory passages.
 Disinfectants in heavy use often lost activity during the 2nd
week.

68.  Don’t use more than 2% Glutaraldehydes to wipe
dental chairs or units
 Most require 20 mins to kill TB bacilli while
phenolic complexes and alcohol acts within 10
mins.
 Uses:
Used for plastic instruments like suction tips,
cheek retractors.
 Most require 2-6 hours for complete sterilization

70.  Restorative and endodontics instruments are
readily processed by autoclave or Chemiclave.
 Sterilization dental cements, calcium sulphate
is done by gamma radiation
 Rubber dam is sterilized by ethylene oxide.
 Carbon steel instruments and burs are best
sterilized by dry heat or chemiclave.

71. Handpiece
 Hand pieces are semi critical items requiring
sterilization
 They must be properly cleaned and lubricated
then autoclaved
 Fiber optic hand pieces dim with repeated heat
sterilization over a period of month or year due
to it’s oil residue and debris baked on the end of
optical fibers.
 It should be sterilized with alcohol or other
organic solvents.
 Ethylene oxide gas is gentlest method of
steriliztion used for handpieces.

72. Impressions
 Precautions are required for IC in making impression.
 Universally apply barrier protection for personnel against
contamination from mucosa, saliva, and blood by use of
adequate PPE, such as gloves, masks, and appropriate
overgarments.
 Impressions should be disinfected with EPA approved
tuberculocidal disinfectant after washing or rinsing with clean
tap water.
 Disinfection is done by 1:10 dilution (0.5%) of household liquid
chlorine bleach for 10 minutes or 5.25% sodium hypochlorite
freshly prepared

73. Dental Radiology
 Standard precautions
 PPE(atleast gloves)
 Clean & disinfect
equipment
 Heat sterilize film holding
device
 Handle exposed X-rays in
Aseptic manner

78. Infection control measures in dentistry are most
vital for mutual health safety of patient and
health care professionals. There are several key
players and elements to achieve the highest
standard of infection control. These include the
Dental health care professionals and the
patients. Rigid implementation of evidences
based infection control measures should be
strictly followed in dental practice.