In depth discussion about all aspects of infection control in the dental practice. universal precautions, special considerations

1. INFECTION CONTROL
IN
DENTISTRY

2. 2
WHY IS INFECTION CONTROL IMPORTANT IN
DENTISTRY?
 Infections present a significant hazard in the dental
environment.
 Both patients and dental health care personnel
(DHCP) can be exposed to pathogens.
 Contact with blood, oral and respiratory secretions,
and contaminated equipment occurs.
 Proper procedures can prevent transmission of
infections among patients and DHCP.

3. 3
RATIONALE
Rationale for infection control is to control iatrogenic,
nosocomial infections among patients, and potential exposure
of care providers to disease causing microbes during provision
of care.
 “Disease control or infection control”: means reducing the risk
of disease transmission.
 “Occupational exposure”: Reasonably anticipated skin, eye,
mucous membrane, or parenteral contact with blood or OPIM
that can result from the performance of an employee's duties.
 “Cross-infection” : disease transfer from one patient to the
other in the dental office.

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ROUTES OF DISEASE TRANSMISSION
 Percutaneous (high-risk): Inoculation of microbes from blood and
saliva through needles and sharps.
 Contact (high risk): Direct contact of non-intact skin or mucous
membranes to infected fluid, splash/spatter; tissue surfaces or
infective oral lesions.
 Inhalation (moderate risk): of airborne microorganisms through
bioaerosols or droplet nuclei.
 Indirect contact (low risk): with a contaminated instrument or
surface.

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CHAIN OF INFECTION
Pathogen
Source
Mode
Entry
Susceptible Host

6. 6
What is decontamination?
Decontamination and Spaulding’s classification
 SANITIZATION: First level of decontamination.
 DISINFECTION :second level
 STERILIZATION: third level

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Categories of tasks, work areas and personnel
 According to OSHA Guidelines:
 Category I : Tasks that involve exposure to blood, body
fluids or tissue.
 Category II : Tasks that involve no exposure to blood, body
fluids or tissues, but may be required to perform unplanned
category I tasks.
 Category III : Tasks that involve no exposure to blood,
body fluids or tissues.

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Adaptation of Spaulding’s Classification
Level Risks Control methods Materials/devices
Critical High Sterilization by:
Autoclave, Chemiclave
Dry heat, Full strength
gluteraldehyde
Items that pierce soft tissue, touch
bone. Scalpel blades, burs, extraction
forceps, elevators, needles, files, bone-
rongers, periodontal instruments, dental
explorers, biopsy punch, endodontic files
and reamers, and implants.
Semi-
critical
High Autoclave, Chemiclave
Dry heat, Full strength
gluteraldehyde
Items that enter the oral cavity, but do not
necessarily penetrate soft and hard tissue.
Mouth mirrors, handpiece, anesthetic
syringes, amalgam condensers, impression
trays, air/water syringe tips, high-volume
evacuator tips.
Non-
Critical
Moderate to
low
Surface disinfection by
intermediate level hospital
disinfectants –, phenols,
iodophors, quaternary
ammonium compounds
Items that do not enter the mouth or
penetrate soft tissues. Chair light handles,
instrument trays, high touch work
surfaces, bracket tables, chair controls,
Air/water syringes, hoses and dental
chairs.
Environm
ental
Low Disinfection with
intermediate to low level
disinfectant
Floors, walls and handles, not high touch
surfaces.

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Critical instruments Semicritical instruments
Non critical
instruments

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PERSONAL PROTECTION
Immunization Practical Barrier Techniques
Immunization of dental health care personnel
 Routine immunization for all common childhood diseases.
 Three areas of concern:
 Immunizations at the time of employment
 Immunization regimens which require booster doses
 Post-exposure

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Proposed protocol for HBV vaccine for Dental Health Care Workers in India
 At the time of employment:
three 1 ml doses at 0, end of 1 month and 6 months i.m.
 If a person is not immunized and is exposed to an infected patient’s body
fluids: A combination of Hepatitis B vaccine and an immunoglobulin (HBIg)
within 24 hours of exposure.
 If exposed person does not want to take the immunization:
two doses of HBIg – dose 1 within 24 hours
- dose 2 25 to 30 days after exposure.
Proposed protocol for HBV vaccine for dental undergraduate and postgraduate
students and dental teaching faculty in India
 Mandatory to be vaccinated against Hepatitis B with a three- dose regimen
and a booster.
 Dental assistants, hygienists, mechanics and all those who come in direct
contact with patient care, cleaning and sterilization of instruments in the
institution.
 Mandatory for institutions to provide free vaccinations.

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STANDARD / UNIVERSAL PRECAUTIONS
 CDC recommends that all patients be treated as potentially
infectious.
 Appropriate level of infection control measures apply to all
patients.
 Level of infection control should be based upon the clinical
procedure to be carried out and reasonably anticipated risk.
 Standard Precautions apply to blood and also
- Body fluids, secretions, and excretions except sweat,
whether or not they contain blood
– Non-intact (broken) skin
– Mucous membranes
– Saliva has always been considered a potentially infectious
material in dental infection control

14. Hand hygiene
Gloves
Mask, eye protection
Clean environment
Clinical Waste
Patient Care
Equipment
Linen
Body fluid
spills
Accommodation
Preventing
exposure
Apron, Gown
There are 11
elements to
Standard Precautions

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HANDWASHING AND HANDCARE
Why Is Hand Hygiene Important?
 Hands are the most common mode of
pathogen transmission
 Reduce spread of antimicrobial resistance
 Prevent health care-associated infections

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 Hands Need to be Cleaned When
 Visibly dirty
 After touching contaminated objects with bare hands
 Before and after patient treatment (before glove
placement and after glove removal).
 RATIONALE FOR HANDWASHING:
 To reduce the number of microbes on the hands by
the process of cleaning mainly, apart from the
antimicrobial effect of germicidal soap.

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What should one use?
 Washing hands with plain soap and water
 Washing hands with water and antimicrobial soap
 Chlorhexidine gluconate – 0.75% to 4% concentration (CHG) –
dispensed as liquid soap or foam
 Parachlorometaxylenol (PCMX) liquid
 Iodine liquid or Triclosan liquid, gel or foam
 CHG 4% – as surgical scrub.
 Hand –sanitizers : alcohol-based
: without alcohol
 Recommended only when handwashing is impractical or cannot be
done.
 Limitation: do not clean hands adequately.

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Surgical soaps should have following properties:
 Substantivity or residual action
 Broad-spectrum antimicrobial activity
 Good kill-rate (i.e., fast or rapid action and reduce the
bacterial load efficiently)
 Good detergent
 Non-irritating to skin
 Fast-acting

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GLOVES
 Pathogenic microorganisms in blood, saliva and plaque can
contaminate the hands of DHCP;
 These microorganisms can infect the host by passing through
dermal defects, and they can contaminate instruments and
surfaces.
 Gloves prevent cross-contamination to patients and also protect
the hands of oral health care providers.
 Gloving is not a substitute for handwashing!

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TYPES OF GLOVES
 Single-use disposable non-sterile exam gloves
 Single-use disposable sterile surgical gloves
 Over-gloves or food handler gloves
 Utility gloves

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Recommendations for gloving
 Hands must be washed before gloving and after removing gloves.
 Check gloves for cuts or defects.
 Double gloving reduces the chances of contamination through
inherent pin-holes.
 Reuse of gloves increases risks. Microorganisms may enter
inherent pin-holes or tears.
 Washing gloves weakens them, makes them tacky.
 Gloves must be worn (clean, non-sterile gloves are adequate for non
invasive procedures) when in contact with blood, body fluids, secretions,
excretions and contaminated items / equipment; before touching mucus
membranes and non intact skin.
 Gloves may need to be changed between tasks and procedures on the same
patient.

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MASK, PROTECTIVE EYEWEAR and FACE
SHIELD
 A mask, eye protection or face shield must be
worn to protect mucous membranes of the
mouth, eyes and nose if there is a risk of
splashing or spray of blood or other body
fluid.
 Masks reduce infectious aerosol inhalation;
and protect mucus membranes from direct
contamination.

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MASKS
 Masks have 3 layers:
- outer (aesthetic) layer
- middle (fluid shield) layer
- inner layer
 Masks should have at least
95% bacterial filtration
efficiency for small particle
aerosols (3.0-3.5 µm).
 “Strike through”: passing of
liquids from outer to inner
surface.
 Mask worn for longer than 20
minutes – the outer surface
becomes a nidus for
pathogenic bacteria.
Fluid shield mask
1: outer facing
2: filter media
3: Loncet breathable film
4: inner facing

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Protective eyewear
 Prevent physical injury, as well as infection.
 With top and side shields – best protection;
 With face shields (masks should be worn
with face shield)
 Contaminated eyewear : wash, rinse and
disinfect
 Wear during lab. Work, reprocessing of
instruments, trimming models, dentures,
cutting wires

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Chin length face shield
with protective
eye glasses

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Protective clothing: Apron / Gown / Footwear
 Fluid resistant full-sleeved gown to protect the uniform from:
– soiling during procedures and patient care activities that are
likely to generate splashes or sprays of blood or body fluids.
– contamination with micro-organisms when bed-making, any
direct patient care or direct contact with the environment of
an isolated patient.
 When removing visibly contaminated clothing, fold the soiled
area inside.
 Send to commercial laundry or wash with hot water at 80º C for
10 minutes using strong detergent and bleach, if possible.
 Always remove protective clothing before leaving the surgery.
 Use protective footwear, to prevent contamination of the feet,
e.g. during operations. Remove contaminated footwear when
procedure is finished.

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Preventing Occupational Exposure
 Cover all cuts and abrasions with waterproof dressings.
 Use devices such as Pocket Mask as an alternative to
mouth-to -mouth resuscitation.
 Take care to prevent sharps injuries.
 Precautions:
 Point sharp end away from the hand.
 Pick up sharp instruments individually
 Do not touch rotating instruments
 Dispose immediately after use
 Wear heavy utility gloves
 Recapping dental syringes:
 Do not remove uncapped needle from syringe.
 Never recap needle with both hands
 Use re-sheathing device
 Do not bend, break or otherwise manipulate by hand
 Dispose into solid sharps container

29. 29

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Blood and Body Fluid Spillages
 Disinfect all blood and body fluid spillages immediately
wearing protective clothing (gloves, apron and if risk of
splash, goggles).
 Completely cover either by disposable towels, which are then
treated with 10,000 ppm sodium hypochlorite solution or by
sodium dichloroisocyanurate granules. At least 5 minutes must
elapse before the towels etc are cleared and disposed of as
clinical waste.
 Wear appropriate protective clothing, which will include
household gloves, protective eyewear and a disposable apron
and, in the case of an extensive floor spillage, protective
footwear. Good ventilation is essential.

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 Ensure that the clinical areas are clean.
 Particular attention must be paid to cleaning of
horizontal surfaces, floors, beds, bed-side equipment
and other frequently touched surfaces.
 If areas are not clean the domestic supervisor must be
informed.
Environment

32. Clinical Waste: Recommended labeling and
color coding
COLOR
CODING
TYPE OF
CONTAINER
WASTE CATEGORY TREATMENT
OPTIONS
YELLOW Plastic bag Human anatomical waste, animal
waste, microbiological & biotech.
waste. Solid waste (items
contaminated with blood/body
fluids, eg. Cotton, soiled dressing,
etc.)
Incineration / deep
burial
RED Disinfected
container /
plastic bag
Microbiological & biotech waste,
disposable items other than waste
sharps, such as tubings, catheters,
i.v sets, solid waste.
Autoclaving /
microwaving / chemical
treatment
BLUE / WHITE
TRANSULECT
Plastic bag /
puncture proof
container
Waste sharps, disposable items. Autoclave / microwave
/ chemical treatment &
destruction / shredding
BLACK Plastic bag Discarded medicines, cytotoxic
drugs, incineration ash, chemical
waste.
Disposal in secured
landfill.

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Additional Measures
 Rubber dams
 Surface covers
 High volume aspiration
 Pre operative patient rinse
 Pre treatment tooth brushing
 Use of rubber cups instead of
bristle brushes during polishing
 Antiretraction valves
 Flushing water through the
handpiece between patients

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Surface covers
 Single-use disposable, water proof barriers
 Light handles, hand operated chair controls,
suction hoses, chairs, bracket tables
 clear plastic wrap, aluminium foil, paper
with impervious plastic backing,
polyethylene sheets and tubing.
 Must be replaced after each patient and
disposed of as contaminated waste

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CONTAMINATION DURING DENTAL PROCEDURS

36. 36

37. 37
Decontamination of instruments and
equipment
 3 stages:
 Pre-sterilization cleaning
 Sterilization
 Storage

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Pre-sterilization cleaning
 Separation of waste and instruments.
 Instruments securely taken to the reprocessing area –
handpieces removed, all other items need to be cleaned first.
 Cleaning of instruments:
 To reduce the bioburden, remove accumulated debris.
» Hand Scrubbing Ultrasonic Cleaning
 Inspection and packaging of cleaned instruments.

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Inspection and packaging of cleaned instruments
 After sonication – rinse, dry, inspect for residual debris.
 Packing of instruments prior to sterilization will depend
upon the type of sterilization, and nature of items to be
sterilized.
 Packaged instruments can be stored; non packaged
instruments have to be used immediately.
 Clearview sterilization pouches – single-wall paper, sealed
nylon, and paper/plastic pouches.
 If instruments are to be cold sterilized, they should not be
packaged.

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INSTRUMENT STERILIZATION
PHYSICAL AGENTS CHEMICAL AGENTS
• Heat – moist 1. Agents acting on the cell membrane
- dry - Surface acting agents (quaternary
ammonium compounds)
• Ionizing radiation - Phenols
X-rays - Organic solvents (alcohol, chloroform)
ß-rays 2. Agents that denature proteins
Gamma rays - Acids and alkalies
• Ultraviolet rays 3. Agents acting on functional groups of
• Filtration proteins
- Heavy metals (copper, silver, mercury)
- Oxidizing agents (iodine, chlorine, hydrogen
peroxide)
- Alkylating agents (formaldehyde, ethylene
oxide)

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MOIST HEAT
I. Temp. below 100°C : a. HOLDER METHOD
b. FLASH METHOD
II. Temp. around 100°C : a. TYNDALLIZATION
b. HOT WATER BOILERS
III. Temp. above 100°C : AUTOCLAVES
 Mechanism of microbial inactivation by moist heat:
 Structural damage to cell membrane.
 Coagulation of proteins, and denaturation of spore enzymes.
 Damage to bacterial chromosomes.

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STEAM AUTOCLAVE
 Charles Chamberland in 1879.
 Sterilization using steam under pressure
 Temp.-time combinations:
 Temp. °C (Pressure) Minimum hold time
 134-138 ( 30 psi) 3-5 min.
 121-124 ( 15 psi) 15-20 min.
 Characteristics :
 Destroys all forms of microbial life, including bacterial endospores in the
recommended time;
 Additional ‘safety factor’ interval must be allowed…. Reach and maintain
121°C for 45 min.
 Sterilization intervals vary with load size, nature of materials, instruments;
and packaging.
ADVANTAGES DISADVANTAGES
-short cycle time - Corrosion of unprotected carbon steel
-Good penetration - Dulling of cutting edges
-Wide range - May destroy heat sensitive materials.

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 Areas of problems:
- Faulty preparation of materials (packaging)
- Improper functioning of sterilizer (temp. / pressure)
- Presence of air in chamber ( delay upto 10 times longer)
- Excess water in steam ( passageway for microorganisms)
- Corrosion of carbon steel instruments (1% sod. Nitrite)
 Acceptable materials:
- cloth goods, high quality S/S instr., glass slabs, stones, dishes, heat resistant
plastics, handpieces that can be autoclaved.
 Limitations of use:
- rusting/corrosion of carbon steel instr.
- needles, oil, wax, dry powder should not be autoclaved
 Other types:
Statim cassette autoclave Autoclave with pre-vacuum &
post-vacuum features

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Steam autoclave
Statim autoclave
Chemiclave

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Chemical Vapour Sterilizer Ethylene oxide sterilizer
Parameters: 132°C at 20-40 psi, 20 min. Room temp. (25°C), 10-16 hrs.
Chemical: Deodorized alcohol, formald., Ethylene oxide gas
ethyl methyl ketone soln.
Advantages: Short cycle High penetrability.
No rusting Suitable for heat labile materials.
Instr. Dry at the end of cycle No residue on evaporation.
Does not dull cutting edges Suitable for materials that cannot
be exposed to moisture.
Suitable for Ortho. s/s wires
Disadv.: Instr. Must be completely dried Long cycle time.
Destroy heat sensitive plastics Tissue irritation
Chemical odor Explosive (“spark shield”)
Acceptable Metal instruments Suction tubing, handpieces, radio
materials graphic film holdrs, prosth. Appl.

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DRY HEAT
 Less efficient than moist heat; bacterial spores are more resistant – may require
temp. of 140°C for 3 hours to get killed.
 Two methods:
Flaming Hot air oven
 Mechanism of action: oxidation, protein denaturation
 Temperature Holding time
› 160°C › 120 min.
› 170°C › 60 min.
› 180°C › 30 min.
Suitable materials: glassware, glass syringes, oils, oily injections, metal instr, mirror
Advantages: - Does not dull cutting edges
- Does not rust or corrode.
Disadv. : - Long cycle
- Poor penetration
- May discolor and char fabric
- Destroys heat labile items.

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IONIZING RADIATION
 X-Rays, ß-Rays, γ-Rays
 Induce defects in microbial DNA.
 Spores are more resistant.
 Used for sterilization of single-use disposable items.
ULTRAVIOLET RADIATION
 UV rays of 240-280 nm most efficient for sterilization.
 Formation of non coding lesions in microbial DNA and bacterial death.
 Used in disinfecting drinking water, air disinfection in hospitals,OTs.
FILTRATION
 Used for sterilization of thermolabile parenteral solutions,serum,etc.
 Membrane filters most commonly used.

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MONITORING OF STERILIZATION
 Studies have shown a 51% sterilization failure rate in dental
sterilizers.
 Two types of tests to check the decontamination process of heat
sterilization:
Chemical indicators Biological monitors
 Test for the sterilizing conditions Monitor the actual sterilization process

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Chemical indicators for monitoring sterilization
 Class 1 - Process Indicators. These are placed on the outside of packs and are
useful in determining which packs have been properly processed versus those
that have not. Class 1 process indicators include autoclave tape and the color
change indicators embedded on the outside of sterilization packaging materials.
 Class 2 - Bowie-Dick Indicators. These show the pass/fail in prevacuum
sterilizers. This test is conducted daily with the chamber empty, during the first
cycle of the sterilizer.
 Class 3 -Temperature-Specific Indicators. These react to one of the critical
parameters of sterilization and indicate exposure to a specific value such as
temperature or psi.
 Class 4 - Multi-parameter Indicators. These react to two or more of the critical
parameters in the same manner as Class 3 indicators.
 Class 5 - Integrating indicators. Designed to react to all critical parameters of
sterilization cycles. When used properly, integrating indicators may serve as
the basis for the release of processed items.

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BIOLOGICAL MONITORS OF
STERILZATION
 Contain bacterial spores that are more
resistant to heat.
 Calibrated concentrations of B.
stearothermophilus or B. subtilis spores.
 Autoclaves & chemiclaves:
B.stearothermophilus
 B. subtilis: dry heat ovens & ethylene oxide
 Intra-office biological monitoring highly
recommended.
 Positive culture results indicate that not all
spores were killed, and items sterilized may
not be sterile.

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CHEMICAL DISINFECTION
 Chemical germicides for disinfection are classified by EPA:
 STERILANTS: All bacterial endospores, vegetative microorganisms, and
viruses.
 HIGH-LEVEL DISINFECTANT: All veg. bacteria, fungi and viruses,
including M. tuberculosis.
 Sterilant for short duration of contact: High-level disinfectant.
 INTERMEDIATE LEVEL DISINFECTANT: Veg. bacteria, fungi and
viruses (1 hydrophilic, 1 lipophilic), plus tuberculocidal.
 LOW-LEVEL DISINFECTANT: Veg. bacteria, some viruses, no kill claim
for M. tuberculosis.
 HOSPITAL DISINFECTANT: Marker organisms, associated with
nosocomial infections
- S.aureus, S. typhimurium, P. aeruginosa

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 Properties of an ideal disinfectant:
- Broad spectrum antimicrobial
- Fast acting
- Not affected by physical factors
- Non toxic, non irritating
- Surface compatibility
- Residual effect
- Easy to use
- Odorless
- Economical.
 Types of Disinfectants:
Immersion disinfectants Surface disinfectants

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Commonly used disinfectants in Dentistry
1. GLUTERALDEHYDE
 EPA recommended for immersion use as sterilant / high-level disinfectant.
 Used as immersion sterilant in dentistry for items that cannot withstand repeated
heat sterilization, and are not disposable.
 Available as neutral, alkaline and acidic soln, conc. of 2 to 3.2%
Advantages Disadvantages
 High biocidal activity. 1. Not an antiseptic.
 Sporicidal at prolonged contact. 2. Only for immersion and not for
 surface use
 Active in the presence of bioburden. 3. Severe tissue / respiratory irritant
 Prolonged shelf and active life. 4. Allergenic
 Generally non-corrosive. 5. Must have good ventilation and
 evacuation
 Compatible with most materials. 6. Can sensitize users
 Penetrates blood, pus & organic debris. 7. Discolors some metals, corrosive
activity may increase on dilution.

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2. CHLORINE PREPARATIONS
A. SODIUM HYPOCHLORITE SOLUTIONS
- Available as household bleach (used in 0.5% conc. sod. hypo.)
- Used as surface disinfectant, and also immersion disinfectant in Prostho.
and as holding solution for endodontic files.
 Advantages Disadvantages
 Rapid antimicrobial action. Very corrosive to metals
 Broad-spectrum kill. Damages plastic and rubber, clothes
 Effective in dilute solution. To be prepared daily
 Economical. Unpleasant odor
Toxic disinfection by-products
Irritate skin, eyes, and mucus membranes.
B. CHLOROUS ACID AND CHLORINE DIOXIDE
- Provide high level disinfection in three minutes.
- Used as surface disinfectant.
Advantages Disadvantages
 3 minutes for disinfection. Highly corrosive to metals and certain
 plastics on prolonged exposure.
 Reports of mucus memb. sensitivity.
 Adequate ventilation needed.

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3. PHENOLS AND DERIVATIVES
- Carbolic acid – classical antiseptic for surgical procedures.
- Synthetic phenols – currently approved by EPA: Biphenols and triphenols.
- Used as surface and immersion disinfectants.
Advantages Disadvantages
 Triphenols are better than Dual Phenols May affect some polymers.
 Broad Spectrum Kill. Some have film accumulation.
 Compatible with most materials. May not be used in neonatal and
pediatric practices due to possible
adverse reaction.
 Residual biocidal action. Should be prepared freshly.
 Fast acting Epithelial toxicity in exposed tissues.
4. IODINE AND IODOPHORS
- Iodine: Oldest skin antiseptic.
- skin irritation, hypersensitivity, corrosion of metals, staining of skin and
clothing.
- Iodophors; complex of elemental iodine or triiodide, with a carrier. Used for
skin preparation for surgery, effective handwashing antiseptics.
Advantages Disadvantages
 Broad spectrum Unstable at high temperatures
 Short biocidal activity Dilution and contact time critical
 Few reactions · Solution to be prepared daily
 Residual biocidal action May discolor some surfaces

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5. Hydrogen Peroxide (0.05%)
- Recently introduced disinfectant.
-Release nascent oxygen, may be of use for surface disinfection.
- Not currently recommended by EPA.
Advantages Disadvantages
 Rapid antimicrobial action Not many reported disadvantages as it
 Broad-spectrum kill is still new in the market
 Effective in dilute solution Can be corrosive on metals, and dangerous
to skin (burns) if used in high conc.
 Prolonged shelf and active life.
 Compatible with metals, plastics
 and impression materials.
 Good for use in dental laboratories.

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6. ALCOHOLS
- Not recommended by ADA or CDC as disinfectant for dental practice.
- Synergistic action with phenolics. May be used for surface disinfection.
Advantages Disadvantages
 70% Isopropyl alcohol, ethyl alcohol- Not recommended for use as surface disinfectants.
Bactericidal, virucidal, tuberculocidal. Activity rapidly diminishes in presence of blood
and saliva.
 Corrosive on metals, destroy rubbers & plastics.
 No sporicidal activity.
7. QUARTERNARY AMMONIA COMPOUNDS
- Cationic surface-active disinfectants.
- Not approved by ADA for instrument or surface disinfection.
Advantages Disadvantages
 Bactericidal at low conc. Not tuberculocidal, sporicidal or virucidal against
 Particularly active against G +ve bacteria. hydrophilic viruses.
 Good cleaners Inactivated by hard water, inactivated by organic
matter.
 Some have M.tuberculosis kill claim Alcohol based quats may affect low viscosity
impression dimensional stability.

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Dental Handpieces
 Contamination:
- Surface contamination by direct contact
- Internal – through cartridge chamber
- Water retraction
 Current Guidelines:
- Sterilization by autoclave, chemiclave or newer generation, shorter
cycle dry heat ovens
- Disinfection – as per manufacturer’s recommendations
 Precautions:
- Proper lubrication prior to sterilization.
- Do not sterilize with other instruments.
- Do not operate handpiece without bur; do not sterilize with the bur
installed.
- Run the handpiece for 20 sec. after use.
- Do not immerse in disinfectant solution, gluteraldehyde should not
be used

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 Newer handpieces
- Can withstand repeated heat sterilization
- Solid fibre-optic rod
- New heat resistant cartridges
- Ceramic bearings
- Lubrication-free handpieces
 Two new systems:
The turbonet system Decident disposable
disinfectant sleeve

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 Rotary instruments:
- Diamond and carbide burs – autoclave
- Carbon-steel burs – chemical vapour sterilization
- glass bead sterilizer
- Retentive pin-twist drills – steam autoclave, chemiclave
 Visible light-curing units
 Triple syringe / air-water syringe
 Ultrasonic scaler
 Compressor:
- Clean, oil-free air
- Good quality filter
- Drain the air receiver daily
- Service regularly

63. 63
Dental Unit Water Supply
 Contamination:
- Retraction valves
- Internal contamination
- Water supply
 Acceptable microbial counts < 500 CFU/ml
 Precautions:
- Check/ Anti-retraction valves
- Sterilization
- Flushing the air/water lines
Disinfection of the Dental unit:
 Within the dental unit:
- Hydrogen peroxide, hypo, gluteraldehyde.
 Disinfection of the unit water line:
- Povidone iodine, sterile water.
 Disinfection of the mains water supply:
- 15% Sod. Hypo. for 10 min. each day.

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INFECTION CONTROL IN PROSTHETICS
 Semi-critical instruments Non-critical:
and items:
- Impressions - Articulators and face bows
- Prosthesis which have been worn - Mixing bowls and spatulas
- Face-bow fork - Shade and mold guides
- Wax knife - Prosthetic rulers
- Prosthesis at try-in stage - Wax rims (discard)
- Metal dispensing syringes
for impressions
- Bite blocks
- Polishing stones and rag wheels
- Impression trays returned from the lab
( Al. or Cr. Plated-heat sterilization,
plastic trays-discard)

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Impressions
 Rinse under running water
 Alginate impressions: hypo 1:5 or 1:10; 2% gluteraldehyde
 Results: insignificant distortion for study casts, not for master casts;
surface quality not adversely affected
 Reversible hydrocolloid impressions: iodophor (1:213), bleach
(1:10), 2% gluteraldehyde
 ZOE and compound impressions: limited data available
ZOE – 2% gluteraldehyde or iodophor; compound – hypo 1:10
 Elastomeric impressions: gluteraldehyde 1 or 2 % ,iodophor, 5.2%
sodium hypochlorite, chlorine dioxide (diluted)
 Prosthesis:
Metal dentures Acrylic dentures
- Iodophors – 1st choice - Sodium hypochlorite
- Hypo 1:5 for 5 min. - Gluteraldehyde with phenolic
buffer (sporicidin) should not be used

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Orthodontics
 Orthodontists have second highest incidence of Hepatitis B among
dental personnel.
 Orthodontic pliers – damage after repeated autoclaving
- lubricate the hinges
- dip in 1% sodium nitrite
 Chemical vapour sterilization – minimal damage
 Convection heat, rapid heat sterilization
 Bands, wires, brackets – band cassettes – rapid dry heat, steam or
chemical vapour sterilization
 2% gluteraldehyde overnight

67. 67
Endodontics
 Precleaning disinfection: holding
solution; synthetic phenols, hypo
5.2%
 Ultrasonic cleaning
 Sterilization: instrument trays –
chemiclave or autoclave
 Gutta percha points: hypo 1:5 for 5
minutes
 Glass-bead/hot salt sterilizers
 For endodontic files and rotary instruments.
 Temp. 218-246°C for a minimum 15 sec.
immersion
 Hot salt is preferable to glass beads

68. 68
Dental Radiology
 X-ray equipment – surfaces should be
covered or disinfected after use
- X-ray cone, tube head, exposure control and
panels
- Non-disposable film holders , panoramic bite
blocks
– autoclave, chemiclave
 Wear gloves while taking radiographs
 Contamination of radiographs: saliva, blood
- Plastic envelopes or cling films
 Dark room and radiographic processing
equipment:
- Disinfect – counter tops, shelves, process tank
covers
- Wear gloves while processing films
- Loading compartment should be disinfected

69. 69
Oral Surgery / Implantology
 Additional measures
 Precautions-
- Thorough hand-scrubbing
- Sterile disposable gowns,masks, head covers, eye protection
- Contamination of surfaces should be minimized
- Pre-operative rinsing, swab the incision area
- Sterile irrigant or coolant
- Proper reprocessing of instruments
 Extracted teeth, biopsy specimens and tissues
- Potentially infectious, medical waste
- Decontamination by heat sterilization, immersion in 5000ppm bleach,
7% H2O2 or gluteraldehyde; storage – 10% formalin.
- Research purpose – 0.05% thymol solution

70. 70
Electrosurgery and LASER
 Smoke and by-products
 Toxic gases – HCN, Benzene, Formaldehyde
 Tissue debris, microbes and viruses
 Full PPE, high speed suction, improve air circulation
New emerging diseases – Creutfeldt Jakob Disease (CJD)
and Prion related diseases
A type of a fatal degenerative disease of central nervous system
Caused by abnormal “prion” protein
 also been identified in the tonsils, eye tissue, and pituitary glandular
tissue.
One case per million population worldwide
Prions are resistant to conventional physical and chemical methods of
decontamination.

71. 71
 If a patient with known status, only treat urgent
condition with following additional precautions:
 Use single-use disposable items and equipment
 Consider items difficult to clean (e.g., endodontic
files, broaches) as single-use disposable
 Keep instruments moist until cleaned
 Clean and autoclave for longest cycle; upto 1
hour sterilization time.
 Do not use flash sterilization

72. Toothbrush disinfection
What is the need for toothbrush disinfection?
We, as clinicians talk so much about daily disinfection procedures
for our instruments and working environment…
However, we neglect to disinfect the one thing that we use to clean
our mouth daily…..our toothbrush.
Remember….the most fertile breeding ground for the microorganisms
in our bathroom is our “toothbrush”.
Microorganisms including Streptococcus mutans, Bacteroids,
Clostridium, Staphylococcus, alpha hemolytic streptococci,
Candida albicans, and others have been isolated from
toothbrushes.
Studies have shown intra-oral translocation of these bacteria. Oral
hygiene aids can harbor a wide range of microorganisms, also
contribute to bacteremia, especially in patients with severe
periodontitis.

73. Options for toothbrush disinfection
 Chemical Disinfectants: 1% sod. hypochlorite and 0.12% CHX for
20 hours
 Listerine for 20 minutes after brushing.
 Brush sprays: Solution consisting of activated ethanol 40% v/v with
a biocide (parabens).
 UV light sanitizers: Constant stream of UV light for 3 min.
 Modified brushes:
 Ozone toothbrush: Perforated brush head for improved hygiene.
- Venturi and coanda effects.
 Coated toothbrush filaments:
- Zeolithic crystals: crystals with Ag and
Zn ions; long-term contact antibacterial
activity.
- CHX Coatings

74. 74
NEWER TECHNOLOGIES ON THE HORIZON
E-BEAM STERILIZATION
 E-beam, a concentrated, highly charged stream of electrons, generated by the
acceleration and conversion of electricity. High-energy electron beams are
typically required to achieve penetration of the product and packaging.
 Mechanism of action: High energy electrons alter various chemical and
molecular bonds, including the reproductive cells of microorganisms.
 Adv. – short exposure time; compatibility with most materials, including
plastics and resins; no residues.
 Method of choice for processing for products of high volume/low value such as
syringes, or low volume/high value such as implants.
 One of the cheapest methods for terminal sterilization of products and
packages.

75. 75
HYDROGEN PEROXIDE GAS PLASMA
 The system injects and vaporizes a solution of 59% hydrogen peroxide into
the chamber, killing any bacteria on any package and product surfaces the
vapor can reach.
 Next, an electromagnetic field is created in the chamber, creating a
plasma cloud that generates free radicals that kill any remaining
bacteria. At the end of the process, the free radicals lose their high
energy, and the hydrogen peroxide converts to water and oxygen
molecules.
 Low-volume, high-value devices, particularly biological tissues, and implants.
 Problems: Small sterilizer volume chamber; expensive; low
penetrating ability; not effective with paper, cellulose, linen.

76. 76
BRIGHT LIGHT
 Another emerging technology not currently in wide use but still promising is
the use of bright light.
 Short pulses of high-intensity, broad-spectrum white light to kill
microorganisms without heat, chemicals, or ionizing radiation. The
light lasts for a few hundred millionths of a second and is 20,000 times
brighter than sunlight.
The light can go through any material that can transmit the appropriate
wavelengths, such as polypropylene and polyethylene.
 The pulsed light offers the potential to perform terminal sterilization
on top of aseptic processing for injectable and parenteral fluids.

77. 77
OZONE
 For instruments sensitive to repeated heat and moisture cycles, molecular
ozone is a low-temperature sterilization process.
 oxygen gaseous ozone.
electric current
 70 to 90% humidification phase.
 The resultant gas is then vented into a sterilization chamber where the
microbes are eliminated through oxidation.
 This system is both non-toxic and environmentally sound.
 Disadvantages: limited penetrability, possible degradation of some plastics
and possible corrosion of metals.
 This alternative is still in research and development and is not available at
this time.

78. 78
SOME IMPORTANT FACTS RELATED TO
DISINFECTION OF HIV
 Available evidence indicates low occupational risk for HIV infection.
 Risk of seroconversion after needlestick exposure to HIV infected blood….less
than 1%.
Survival of HIV after drying
 Studies carried out using highly concentrated HIV samples.
 Drying reduces the amount of infectious virus by 90-99%.
 Drying of infected blood/body fluids reduces the theoretical risk of transmission to
essentially zero.
Susceptibility of HIV to disinfection by disinfectants & U.V. light
 1% and 2% gluteraldehyde inactivated cell-free HIV within one minute; cell-
associated virus more resilient.
 70% alcohol failed to inactivate the virus.
 Chlorine, phenols, quaternary ammonium compounds –effective.
 Effectiveness of disinfectants compromised in presence of blood.
 U.V light and boiling water – effective.

79. 79
Post-exposure management
 Clean the wound. Do not scrub.
 Counseling about the risk of infection.
 Test the blood of both the exposed and the person causing the exposure.
 Seek medical evaluation.
 HIV Blood tests and treatment recommendations:
 Patient’s antigen status Recipient of exposure
- Diagnosed AIDS, anti- HIV 1a. Anti-HIV positive: post test counseling,
positive, refuses testing or medical evaluation.
unknown source. 1b. Anti-HIV negative: counseling and
repeat testing at 6, 12 and 24 weeks.
- Anti-HIV negative. 2a. Anti-HIV positive: counseling, medical
evaluation.
2b. Anti-HIV negative: counseling and
optional follow-up at 12 weeks.

80. 80
PHYSICAL DESTRUCTION OF HEPATITIS –B VIRUS
 I. CHEMICAL COMPOUNDS
 Number of commonly used chemical germicides are active against HBV at
varying concentrations. Based on the HBV-destroying activity, the various
chemical compounds show the following gradient:
 Oxygen releasing acids (peroxide, per acetic acid) > aldehydes (gluteraldehyde,
formaldehyde) > halogens (sod. Hypo.) > phenolic compounds > PVP iodide &
alcohols.
 According to studies, HBV is more sensitive to alkaline conditions than acidic
conditions.
 II. PHYSICAL PROCEDURES
 Boiling at 100°C after a reaction period of 3 min. - >99% HBV destroying
activity.
 Autoclaving at 121°C for 15 min. – destroyes most viral proteins.
 Autoclaving at 134°C for 15 min. – destroys all viral proteins.
 III. COMBINED PHYSICAL AND CHEMICAL PROCEDURES
 Additive effect on destruction of HBV.

81. 81
Status of Dental Infection Control and Safety in India
 Level of infection control in India still far behind.
 Requires more efforts and development of formal programs.
 Policy through grass-roots education should address the following:
- Training for dental students & practitioners.
- Introduction and provision of instruments and equipment needed.
- Craft the recommendations.
- Surveillance of safe practices.
- Dissemination of information for patients.
- Setting up HIV and blood borne disease dental care centers.
- Expanding the duties of Public Health Dentistry/ Community
Dentistry Departments to provide out-reach dental care to rural HIV
and other BBP infected patients.

82. 82
CONCLUSION
 Level of infection control in India still far behind, and a number of questions
regarding infection-control practices and their effectiveness still remain
unanswered.
 Requires more efforts and development of formal programs.
 Policy through grass-roots education should address the following:
- Training for dental students & practitioners.
- Surveillance of safe practices.
- Establish routine evaluation of the infection-control program, including
evaluation of performance indicators.
- Setting up HIV and blood borne disease dental care centers.
- Expanding the duties of Public Health Dentistry/ Community Dentistry
Departments to provide out-reach dental care to rural HIV and other BBP
infected patients.

83. 83
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2. Cottone JA, Terezhalmy GT, Molinari JA, editors. Practical Infection Control in
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3. Kohli A, Puttaiah R. Infection Control and Occupational Safety
Recommendations for Oral Health Professionals. Dental Council of India, New
Delhi.
4. Vishwanathan R, Ranganathan K. HIV disease in India – Handbook for Dental
Professionals. Produced by Ragas Dental College Chennai in collaboration with
YRG Care – Chennai. Dental Council of India, New Delhi.
5. Prabhu SR, Rao B, Kohli A. HIV and AIDS in Dental Practice – Handbook for
Dental Practitioners. Dental Council of India, New Delhi.

84. 84
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11. Park K. Park’s Textbook of Preventive and Social Medicine. 19th ed. Bhanot
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