Presented By:Sushant Kumar Swatantra

Contents:

Definitions Classification of instruments Decontamination cycle Sterilization and its methods Principles of sterilization Disinfection and its methods Agents used for disinfection Personal barrier protection Conclusion References

InfectionIt is the process of invasion of the tissue by organisms

characterized by their multiplication in the body of the host to produce disease.

Infection control: In medical care, institutional procedures and policies

for monitoring and attempting to control the transmission of communicable diseases.

This includes establishing mandatory sanitation, sterilization, hand hygiene, and isolation procedures.

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Why Is Infection Control Important in Dentistry?

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

Modes of Transmission

Direct contact with blood or body fluids

Indirect contact with a contaminated instrument or surface

Contact of mucosa of the eyes, nose, or mouth with droplets or spatter

Inhalation of airborne microorganisms

Standard Precautions

Apply to all patients

Integrate and expand Universal Precautions to include organisms spread by blood and also Body fluids, secretions, and excretions except

sweat, whether or not they contain blood Non-intact (broken) skin Mucous membranes

Universal precaution Vs Standard precaution

According to Centers for Disease Control, STANDARD PRECAUTION is the outgrowth of UNIVERSAL PRECAUTION (UP). Universal Precaution was first introduced on 1987 to prevent the spread or the transmission of blood borne pathogens to the health care providers. However, on 1996 the concept of standard precaution was established to expand the course of universal precaution .

STANDARD PRECAUTION now constitutes the primary strategy to prevent the transmission of infectious agents not only to the health care personnel but also to patients and hospital visitors.

CleaningA process which removes visible contamination, but

does not necessarily destroy microorganisms.

AsepsisThe methods which prevent contamination of wounds and other sites, by ensuring that only sterile objects and fluids come into contact with them, and that the risks of air-borne contamination is minimized.

AntisepsisThe prevention of infection, usually by inhibiting the growth of bacteria in wounds or tissues.

Antiseptics

Chemical disinfectants which can be safely applied to skin or mucous membrane and are used to prevent infection by inhibiting the growth of bacteria.

Decontamination

The process of rendering an article or area free of danger from contaminant, including microbial, chemical, radioactive and other hazards.

Disinfection

Process which reduces the number of microorganisms

present, but may not inactivate some viruses and

bacterial spores.

Sterilization

Process that destroys, eliminates or inactivates (kills) all forms of microbial life including bacterial endospores.

Depending on the risk of transmitting infection instruments are classified as:

A. Critical :-(high risk)

Instrument that come in contact with Critical surfaces such as Sterile tissue, body cavity, bloodstream

instruments that penetrate soft tissue or bone

Enter sterile body cavity such as endodontic microsurgical procedures

Should be sterilized

Eg. chisel, scalpel, forceps, burs, periodontal scalers

B. Semi critical :(medium risk)

Instruments that come in contact with semi critical surfaces such as Intact oral mucosa, non-intact skin

contact with the oral tissue/body fluids such as gingiva, teeth

if sterilization not possible than high level disinfection

Eg.- mouth mirror, explorer and amalgam condensers , air water syringe, dental handpieces

C. Non Critical :(low risk)

Instruments or medical devices that comes in contact with the non critical surfaces such as intact skin.

Intermediate level or low level disinfection or detergent and water washing

E.g. external components of x-ray head, chairs, supporting equipment of dental unit, stethoscope

USE

CLEANING

DISINFECTION

INSPECTIONPACKAGING

STERILISATION

STORAGE

DECONTAMINATION CYCLE

proper sterilisation relies on a combination

of processes which together

form an infection control system

Sterilization and its methods

3 most commonly used methods of sterilization are:

Steam autoclave

Dry heat oven (dryclave)

Unsaturated chemical vapour sterilizer(Chemiclave)

Other methods are:

Exposure to ethylene oxide gas

Boiling water

Ionizing radiation

Principles of sterilization

All instruments should be thoroughly cleaned

Essential is that sterilizing agent should be in contact with every surface of each item to be sterilized for specified period of time at the specified temperature.

All sterilizing equipment should be regularly maintained.

Manufacturer’s instruction should be strictly adhered to.

Moist/ steam heat sterilization (Autoclave)

PRINCIPLE:

Water boils when its vapor pressure equals that of the surrounding atmosphere

Hence when pressure inside a closed vessel increases , the temperature at which it boils also increases.

Saturated steam has penetrative power

When steam comes into contact with a cooler surface, it condenses into water and gives up its latent heat to that surface.

1600ml of steam at 100°C and 1

atmospheric pressure

1 ml of water at 100°c

Releases 518 calories of heat

• This large reduction in volume sucks in more steam to the area & the process continues till the temperature of that surface is raised to that of the steam

• The condensed water ensures moist conditions for killing the microbes present

Types of autoclave:

1) Downward (gravitation) displacement sterilizer

2) Steam sterilizer with pre and post vacuum processes

Phases of Sterilization :

1. Pre-treatment phase/heat up cycle: All air is expelled by a number of pulses(at least 3) of vacuum and introduction of steam.

2. Sterilizing phase/Sterilization cycle: Temperature is increased sufficiently at which sterilization is to take place.

Actual sterilizing period is called Holding/plateau time, starts when the temperature in all parts of the autoclave chamber and its content has reached the sterilizing temperature.

3. Post treatment phase / depressurisation cycle and drying cycle: Steam or revaporized condensed water is removed by vacuum to ensure that the goods are dried rapidly.

Time,temperature and pressure for autoclaving are :

Pressure (Psi) Temperature (°C) Time(mins.)

15 121 15

20 126 10

30 134 3

Packaging and marking of packs

Done before sterilizing to prevent instruments from being contaminated after sterilization till it is opened and used.

Autoclave packaging should be porous to permit steam to penetrate and reach the instruments. Eg. Fabric, paper, muslin cloth pouches, nylon bags etc.

Packs should have some external indication, showing the packs have been processed in form of marking.

Each pack must be labeled with content, date of sterilization, autoclave number, load number.

ADVANTAGES

Most rapid and effective method of sterilization.

Provides excellent penetration.

DISADVANTAGES

Corrosion of carbon steel instruments.

May damage plastic and rubber items.

Unprotected cutting edges may become dull.

Dry heat sterilization (Dryclave)

It effectively sterilizes instruments at high temperature above 160°C.

Basic action involves dehydration and oxidation of microorganism.

Achieved by 2 methods:

1) Dry heat oven type sterilizer(static air):-160 °C for 60-120 mins

2) Dry heat-rapid heat transfer(forced air):

- 6 mins for unwrapped instruments at 190 °C.-12 mins for wrapped instruments at 190 °C.

Advantages:

Rapid cycles are possible at high temperature.

Burs &carbon steel instruments do not rust if they are well dried before sterilization.

Large load can be placed.

Low cost of equipment.

Disadvantages:

Heat sensitive items like rubber or plastics may be damaged.

At lower temperature ,sterilization cycles are prolonged.

Sterilization is ineffective if there is heavy instrument load and crowding.

Unsaturated chemical vapoursterilizer (Chemiclave)

This sterilizer is same as autoclave unlike it uses special chemical solution containing formaldehyde and alcohol.

The chemical vapour kills microorganisms by destroying vital protein systems.

STERLIZATION CYCLE FOR CHEMICLAVE:

Temperature (°C) Pressure(Ibs) Time(minutes)

132 20 20

Advantages:

It does not corrode metals.

Load comes out dry.

Disadvantages

High cost of equipment.

Vapour odor may be offensive and requires increased ventilation.

The solution supplied by manufacture has to be used.

Handpieces cannot be sterilized by this method.

ETHYLENE OXIDE STERILIZATION

It is an excellent sterilizer of heat sensitive items as well as ideal for electric equipment ,flexible fiber endoscopes and photographic equipment.

This method uses automatic devices filled with ethylene oxide gas at temperature below 100˚c to sterilize complex and delicate materials.

Ethylene oxide destroys microorganisms by chemically reacting with nucleic acid.

Advantages :

Most gentle for sensitive equipment like hand pieces.

Operate effectively at low temperature.

Disadvantages:

High cost.

Prolonged time.

Best for hospitals not practical for dental clinics

Ethylene oxide gas is potentially mutagenic and carcinogenic.

BOILING WATER

Boiling water produces temperature of 100̊c at normal atmospheric pressure which requires 10 mins exposure to kill bacteria and some viruses.

When the water starts boiling instruments should be kept in it and should be fully immersed in it for 20-30 minutes.

Cutting instruments should not be sterilized by boiling as they loose their sharpness.

IONIZING RADIATION

It is effective for heat labile items .

It is commonly used by industry to sterilize disposable materials such as needles, syringes, swabs, catheters, suture material, cannulas.

High energy gamma rays from cobalt 60 are used to sterilize such article.

If autoclave is not available???

Place all instruments in water immediately after use.

Remove all debris from the instruments by scrubbing with brush in soapy water.

Prepare fire with fuel available.

Put clean instruments in a pressure cooker and add clean water in it.

Place the pressure cooker on the stove and bring it to boil.

Continue heating the pressure cooker on low heat for a minimum of 15 minutes.

Ensure that steam continues to be released from pressure cooker during this time

Remove pressure cooker from stove after 15 minutes and leave it to cool.

Release pressure first before opening the pressure cooker.

Take instruments out of pressure cooker with instrument forceps and dry in clean towel.

Store in a covered box(metal box).

DISINFECTION

Disinfection is a process by which microbes are removed from an object or surface. This does not include bacterial endospores. This process is used to treat articles which do not penetrate the mucous membrane or skin.

Classification of disinfectants

1. Based on consistency

a. Liquid (E.g.Alcohols, Phenols)

b. Gaseous (Formaldehyde vapor, Ethylene oxide)

2. Based on spectrum of activity

a. High level

b. Intermediate level

c. Low level

3. Based on mechanism of action

a) Action on membrane (E.g.Alcohol, detergent)

b) Denaturation of cellular proteins (E.g.Alcohol, Phenol)

c) Oxidation of essential sulphydryl groups of enzymes (E.g. H2O2, Halogens)

d) Alkylation of amino-, carboxyl- and hydroxyl group (E.g.Ethylene Oxide, Formaldehyde)

e) Damage to nucleic acids (Ethylene Oxide, Formaldehyde)

The two methods of achieving disinfection are:

thermal and chemical disinfection.

1. Thermal disinfection (pasteurization)

By using heat and water at temperatures that destroy pathogenic, vegetative agents

Level of disinfection depends on the water temperature and the duration the instrument is exposed to that temperature

2. Chemical Disinfection

The performance of chemical disinfectants is dependent on a number of factors including: temperature, contact time, concentration, pH, presence of organic or inorganic matter and the numbers and resistance of the initial bioburden on a surface.

Chemical agents used are:

Aldehyde (formaldehyde, glutaraldehyde)

Biguanides (chlorhexidine)

Halogens (sodium hypochlorite solution)

2% Glutaraldehyde

Is generally the most appropriate high level chemical disinfectant.

Active against most vegetative bacteria(including M. tuberculosis) and some viruses including HIV ,fungi and bacterial spores.

Can be safely used on metal instruments (< 24 hrs ), rubber, plastics and porcelain.

An immersion time of≥20 min - disinfection6-10 hours - sterilization

Must be used under very strict controlled conditions and in a safe working environment.

Biguanides (Chlorhexidine)

It is active against bacteria but not spores, fungi and viruses.

0.5% chlorhexidine in 70%alcohol is used

Halogens (sodium hypochlorite solution)

Active against bacteria,spores,fungi and viruses including hepatitis viruses.

1:10 freshly prepared sodium hypochlorite solution is an effective surface disinfectant.

Alcohols

Antibacterial activity against some Gram -ve, some Gram +ve bacteria (especially against M. tuberculosis), not effective against spores, viruses

It acts by denaturing proteins

70% alcohol is most effective than high concentration

Don’t function as disinfectant when simply wiped (must have minimum of 10 minutes contact)

STERILIZATION OF HANDPIECES

While using hand pieces in patient’s mouth, blood, saliva, tooth cutting debris and restorative materials may be drawn into its working portion. Hence it should be properly sterilized between patient exposure to prevent cross infection.

PROTOCOL FOR STERILIZING HANDPIECES

Clean the handpiece by wiping visible debris using suitable disinfectant such as alcohol.

Run it for minimum of 30 seconds to discharge residual water and air.

Clean it thoroughly with soap and detergent solution.

Reattach handpiece to the unit and run dry.

Lubrication of handpiece should be done before sterilization using lubricant.

Finally place the instruments in paper pack and seal it.

Now handpiece can be sterilized by autoclaving.

INSTRUMENT PROCESSING

DISINFECTION OF DENTAL CHAIR

It is necessary to disinfect the dental chair between appointments to prevent cross contamination.

The chair is prepared as follows:

Pull a large clear plastic cover over dental control unit from front and tuck excess up under the unit.

Pull another bag down over the chair back which also cover chair arm.

Install suction and air/water syringe tips.Place a slender bag over each tip pushing the tip through the end of bag and then sliding the bag to cover all the handle.Forsuction tip wrap autoclave tape at tip/bag junction to secure the bag against creeping and to prevent contamination of handle area.

Install sterilized handpiece .A plastic sleeve may be used to cover the motor end of handpiece.

After completing one appointment remove all the plastic cover and area where previously not covered should be wiped with towel wetted with disinfectant.

Wash the sink with water and disinfectant spray.

DISINFECTION OF ENVIROMENTAL SURFACE OF DENTAL CLINIC

Environmental surfaces such as floors, doors carry a lower risk of disease transmission than the instruments and devices that come into direct contact with patients.

The surfaces should be sprayed, or they should be wiped with disinfectant-soaked towel to remove debris.

Categories of Environmental Surfaces

1.Clinical contact surfaces High potential for direct contamination from spray or

spatter or by contact with DHCP’s gloved hand

Risk of transmitting infections greater

Surface barriers can be used and changed between patients

Clean then disinfect using an EPA-registered low-(HIV/HBV claim) to intermediate-level (tuberculocidalclaim) hospital disinfectant

Clinical Contact Surfaces

2. Housekeeping surfaces

• Do not come into contact with patients or devices.

• Limited risk of disease transmission.

• Routinely clean with soap and water or an EPA-registered detergent/hospital disinfectant.

• Clean mops and cloths and allow to dry thoroughly before re-using.

• Prepare fresh cleaning and disinfecting solutions daily and per manufacturer recommendations.

Housekeeping Surfaces

DISINFECTION OF RADIOGRAPHIC SECTION IN DENTAL CLINIC

The tube head of X-ray machine, X-ray buttons should be covered with plastic bags.

The operator hand should be gloved before taking the radiograph.

Before processing the exposed film it should be washed under running water to remove saliva or blood.

Disinfect the lead apron with disinfectant spray.

WATER BIOFLIM

The interior of small-diameter tubing in dental unit waterlines are sites of biofilm formation.

Water becomes stagnant when the units are not in use.

Flush water lines at the beginning of the day for 30 seconds.

Flushing for several minutes between patients for 20-30 second however, may be valuable in removing contaminants that can enter the water system during patient treatment.

In general, disinfectants are allowed to remain in the lines overnight, and are then flushed from the lines the next morning. If bleach is used, it should be left in the tubing for a short time only, and the system should then be rinsed with copious amounts of water and left to dry overnight.

Disinfectant for dental unit waterlines include hydrogen peroxide, chlorhexidine gluconate, and iodophors.

DISINFECTION OF IMPRESSION

Alginate-immersion in iodophors or 0.5%hypochlorite.

Poly sulfide-immersion in gluteraldehyde, iodophor, 0.5%hypochlorite or phenolic solution.

Silicone-immersion in any disinfectant.

Polyether-sprays and wrap in iodophors ,0.5%hypochlorite.

Hydrocolloid-immerse in iodophor ,0.5%hypoochlorite.

Impression compound-immerse in iodophor, 0.5% hypochlorite.

Categories of task in relation to risk

Category I

Tasks involving exposure to blood, body fluids and tissues

Most tasks performed by the dentist, dental hygienist, dental assistant and laboratory technician falls in this category

Category II

Tasks that do not involve routine exposure to blood, body fluids or tissues

Clerical or non-professional workers who may help to clean up the office, handle instruments or impression materials or send dental instruments to laboratory fall in this category

Category III

Tasks that involve no exposure to blood, body fluids or tissues

Front office receptionist, book-keeper or insurance clerk who doesn’t handle dental instruments and materials

The American Dental Association(ADA) and Occupational Safety and Health Act(OSHA) guidelines advise that all dental office staff in category I and II be trained in infection control to protect themselves and their patients.

OSHA regulation

Occupational safety and health administration(OSHA) is federal agency that establishes regulation to protect employees from unsafe working condition.

They are:

Employers must provide HBV immunization to employees without charge within 10 days of employment.

Employers must require that standard precaution to be observed to prevent contact with blood and other potentially infectious materials.

Employers must implement engineering controls to reduce production of contaminated spatter, mists and aerosols.

Employers must implement work practice control precautions to mimimize splashing, spatter, or contact of bare hands with contaminated surfaces.

Employers must provide facilities and instruction for washing hands after removing gloves.

Employers must prescribe safe handling of needle orother sharp items.

Employers must prescribe disposal of single use needles, wires, carpules and sharps as close to the place of use as possible, as soon as feasible, in hard walled, leak-proof containers that are closable, from which needles cannot be easily spilled.

Contaminated reusable sharp instruments must not be stored or processed in manner that requires employees to reach hands into containers to retrieve them.

Employers must prohibit eating, drinking, handling contact lenses and application of facial cosmetics in contaminated environments, such as operatories and clean up areas.

Blood and contaminated specimens to be shipped, transported or stored should be placed in suitable closed containers that prevent leakage.

Employers must provide a written schedule for cleaning and decontaminating equipment, work surfaces and contaminated floors.

Place reusable contaminated sharp instruments into a basket in hard walled container for transportation to clean up areas.

Employers must provide laundering of protective garments used for universal precautions at no cost to employers.

Personnel Health Elements of an Infection Control Program

Education and training

Immunizations

Exposure prevention and post-exposure management

Medical condition management and work-related illnesses and restrictions

Health record maintenance

Personal barrier protection in the community

Gloves

Medical gloves(latex or vinyl) must always be worn when there is potential for contacting blood, blood contaminated saliva or mucous membrane

Nonsterile gloves for examination and nonsurgical procedures and sterile gloves for surgical purposes

Must not be washed or used for more than one patient

Washing of gloves may cause wicking effect

Disinfecting agents, oils, certain oil-based lotions and heat treatment may cause deterioration of gloves

While cleaning and sorting used instruments, puncture resistant utility gloves should be worn which can be washed inside out, disinfected or steam autoclaved as needed

In 1997, the National Institute for Occupational Safety and Health(NIOSH) issued an alert on preventing allergic reactions to natural rubber latex in the workplace.

NIOSH recommends the selection of products and work practices that reduces risk for allergies.

FDA has issued latex labeling requirements for all items made from or containing natural rubber latex.

While the Center for Disease Control recommends using a new pair of gloves in the medical field for every use, some situations such as a shortage of gloves or an emergency may require multiple uses of gloves.

In this case, it is imperative that gloves are appropriately disinfected using a specific procedure to avoid passing along germs, pathogens, infections or even diseases.

Instructions:

Grab the cuff of one of the gloves to turn inside out and pull halfway off of the hand. Pull the other glove at the cuff to turn inside out and pull halfway off the hand.

When both gloves are halfway off the hands, pull both gloves off from the inside at the same time. Never touch the outer portion of the gloves with your skin.

Soak the gloves in 0.5 percent chlorine solution for at least 10 minutes.

Wash gloves in soapy water inside and out and rinse fully. Test for holes or tears by placing the gloves under water. If any air bubbles appear, throw the gloves away immediately. If no air bubbles appear, let the gloves air dry.

Turn the cuffs of the gloves inside out a few inches and place five to fifteen pairs of gloves onto each steamer pan and cover with the lid.

Steam the gloves for 20 minutes at a rolling boil.

Air dry the gloves in the steamer pan for four to six hours before use and remove with forceps into a disinfected container with a lid.

Instructions for handwashing

At the beginning of a routine treatment period, remove watches, jewelry and rings then wash hands with suitable cleanser

Hands should be lathered for at least 10 seconds rubbing all surfaces and rinsed

Washing should be repeated at least once to remove all soil

Even good quality surgical gloves develop minor pinholes or leaks during vigorous use.

Washing minimizes infection risks secondary to leakage.

Hand cleansers containing mild antiseptic like 3% parachlorometaxylenol (PCMX) or chlorhexidine are preferred to control transient pathogens and to suppress overgrowth of skin bacteria.

Alcohol rubs are also effective against pathogens with less drying effect.

CDC recommends the Dental Health Care Worker(DHCW) who have exudative lesions or weeping dermatitis particularly on the hands, should refrain from all direct patient care and from handling dental patient care equipment until the condition resolves.

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)

When water and soap are not available,

Using hand sanitizer is a good substitute, but it's best when you really know how to use it properly.

Composition of hand sanitizer

Active ingredient:

Isopropanol, ethanol, n-propanol or

Povidone iodine.

Inactive ingredient:

Poly-acrylic acid as thikening agent

Humectants like glycerin or propylene

glycol

Essential oil of plants

Here are some easy steps to follow to make sure that you do it correctly:

Step 1 Squirt the hand sanitizer into the palm of your hand.

Step 2

Start rubbing your hands together gently. Be sure to get every spot and not miss any part. Get in between fingers, under rings and under jewelry. Rub hand sanitizer thoroughly on hands and about two inches up your wrist. Hold hands downward to avoid contamination on the upper part of your arms.

Step 3 Finish. Don't dry your hands on a towel; it will be better

to let them air dry.

How to make your own hand sanitizer?

2/3 cup 99% rubbing alcohol (isopropyl alcohol) or ethanol

1/3 cup aloe vera gel

8-10 drops essential oil, optional (such as lavendar, vanilla, peppermint, grapefruit)

bowl and spoon

funnel

recycled liquid soap or hand sanitizer bottle

Simply mix the ingredients together and then use the funnel to pour them into the bottle. Screw the pump back onto the bottle and it can be used.

Protective eyewear, masks and hair protection

Protective eyewear consists of goggles or glasses with solid side-shields

Put eyewear with clean hands before gloving and remove with clean hands after gloves are removed

Mask should be worn to protect against aerosols

Grasp the mask only by the string or band at the sides or back of the head to remove it

Mask should be changed between every patient or whenever it becomes moist or visibly soiled

Should be discarded when patient is dismissed after treatment instead of wearing it around the neck

Hair should be kept back out of the treatment field

Hair can trap heavy contamination which if not washed away can cause cross contamination

Protective overgarments

Protective clothing such as reusable or disposable gowns, laboratory coats or uniforms worn when clothing is likely to be soiled with blood and other body fluids

Reusable protective clothing washed using a normal laundry cycle according to instructions of manufacturer and detergent

CONCLUSION Pervasive increases in serious transmissible diseases over the

last few decades have created global concern and impacted the treatment mode of all dental health care workers.

The aim of sterilization and infection control is to control iatrogenic, nosocomial infections among patients and potential occupational exposure of care providers to microbes causing disease during provision of care.

To prevent occupational exposure and cross-infection dental health care provider must be knowledgable about the diseases commonly encountered and follow high standards of infection control for the safety of patients and dental health care workers.

REFRENCES Essentials of Preventive and Community Dentistry,

5th edition, Soben Peter Sturdevant’s art and science of Operative Dentistry

,5th edition, Theodore M. Roberson, Harald O. Heymann,Edward J. Swift

Textbook of Oral and Maxillofacial Surgery 2nd

edition, Neelima Anil Malik Preventive and Social Medicine ,20th Edition, Park.K Grossman’s endodontic practice, 12th edition, B.

Suresh Chandra, V. Gopi Krishna http://www.cdc.gov/oralhealth/infectioncontrol/

guidelines/index.htm