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Clean? Disinfect? Sterilize?What does it all mean??

DA 116 Infection Control

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Instruments, supplies, equipment, surfacesAfter each patient treatment procedure is completed

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Clean? (“pre-clean”)• Basic first step of decontamination process

– Reduce the number of microbes and remove bioburden – Prevent debris from harboring microorganisms during

sterilization process

**if a surface is not CLEAN

it cannot be disinfected**

• Remove all disposables and contaminated items from operatory first

• Use soap and water OR an EPA-registered product that cleans and disinfects

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Pre-Cleaning the operatory

• PPE with utility gloves

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Pre-Cleaning Instruments preferred method: mechanical cleaning

Ultrasonic Cleaner Instrument Washer

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Disinfect?• After precleaning• NOT the same as sterilization• Kills most disease-causing microorganisms,

but not spores– Non-pathogenic microorganisms may remain on

an object after disinfection

• Use an EPA-registered hospital disinfectant with tuberculocidal, HIV, and HBV claims– Note: Hydrogen Peroxide is NOT an acceptable

disinfectant

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Levels of Disinfection:

• Low level disinfection: (actually cleaning)– Least effective. Does not kill spores or

Tuberculosis

• Intermediate level disinfection:– Kills TB, which is the most difficult to kill as spores– If you use a process that kills TB spores, you will

also be able to kill other organisms that are easier to kill (HBV and HIV)

• High level disinfection:– Kills some, but not all bacterial spores, including

TB as well as other bacteria, fungi and viruses• Almost as effective as true sterilization but not as

thorough

9Disinfectant Comparisons

note: rubbing alcohol is NOT an approved disinfectant

Disinfectant Level Advantages Disadvantages Required times

Glutaraldehyde High disinfect impressions

CorrosiveEye irritation

10-90 min.

Iodophor Intermediate Fast actingResidual activityCleans and disinfects

discoloration 10 min on surface

Complex (synthetic) Phenolics

Intermediate Fast actingResidual activityClean and disinfect

Skin/mucous irritationNo use on plastics

10 min

Chlorines Intermediate economical Corrosive, skin irritation, must prepare daily

2-10 min

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Disinfecting Sprays

How to Use:For surface disinfection – use the 2 step method.• Clean by wiping surfaces thoroughly with disinfectant and paper towels or 4 x 4 gauze to remove all soils.• Disinfect by reapplying disinfectant, keeping surfaces wet for 10 minutes. Wipe off excess solution after contact time is completed. Place barriers.

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Disinfecting wipes

How to Use:For surface disinfection – use the 2 step method.• To clean, remove one or more wipe towelettes and wipe surfacesthoroughly to remove all soils. Discard used wipe towelettes.• Remove one or more additional fresh wipe towelettes. Reapplydisinfectant to previously cleaned surfaces for a 10 minute contact time.

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Additional Disinfecting Concerns:

Radiography• Film holders and

positioners for digital radiographs should be heat sterilized between patients, UNLESS they are disposable items.

• Sensors for digital radiographs cannot be sterilized and should be covered with a new barrier sleeve for each patient.

Dental Lab• All items used in the

mouth should be cleaned and soaked in a high level disinfectant before sending to the laboratory for processing.

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Sterilize?– Process by which all forms of life are

completely destroyed• destroys all living microorganisms, including bacterial

spores and viruses. Kills good and bad microorganisms, all life

– After proper sterilization, no microorganisms will be alive

– Heat or Liquid Chemical

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Steam under pressure

Steam (autoclave) Flash (Statim)

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Rapid Heat Sterilization

• AKA ‘Statim’• Works like a convection oven, high

temperature plus circulating steam• 375 F degrees (190C) 12 minutes for

wrapped items• 375 F degrees (190C) 6 minutes for

unwrapped items

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Autoclave:

• Uses moist heat to sterilize• Steam under pressure is considered the sterilizing

agent• 15 pounds of pressure per square inch• 250 degrees F (121 degrees C)• For 15-20 minutes for wrapped instruments• 30 minutes for porous materials• Avoid overloading or wrapping instruments too

tightly• Steam must circulate to all surfaces

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Chemical Vapor Sterilizer

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Chemical Vapor Sterilization:

• Combination of heat and unsaturated chemical vapor (produces hot vapors of alcohol and formaldehyde that act as sterilizing agent)

• Chemicals used: alcohol, acetone, ketone, formaldehyde and distilled water

• Advantage: – No corrosion or dulling of instruments– Instruments are dry at end of cycle– All instruments which can be autoclaved, can be

chemiclaved• Disadvantage: needs well ventilated area due to odor• 270 F degrees (131C) 20-40 minutes 20 PSI pressure• Clean, rinse and dry instruments well before

sterilizing; wrap loosely

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Dry Heat Sterilizer

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Dry Heat Sterilization:

• “Baking” – high temperature is sterilizing agent• 320 F degrees (160C degrees) = 2 hours (120

minutes)• 340 F degrees (170C degrees) = 1 hour (60 minutes)• Advantage: no rust or corrosion or dulling sharp

edges• Disadvantage: some plastics, gauze, impression

trays cannot tolerate high temperatures, can cause damage

• Instruments must be clean and dry prior to sterilization

• Usually requires special metal instrument trays used during sterilization

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Glass Bead SterilizerEthylene Oxide Sterilizer

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Glass Bead Sterilizer:

• *no longer OSHA accepted

• Previously used chairside during endodontic procedures to sterilize files between canals – used on the same patient

• Consists of glass beads, metal beads and salt

• 450 degrees F, for 20-30 seconds

• The set of files are then autoclaved between patients

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Ethylene Oxide Sterilizer

• This is another chemical sterilization method

• Considered a poisonous gas

• Runs on a 10-16 hour cycle

• Used in hospitals but not in dental settings

24Liquid Sterilant (cold sterilant or high-level disinfectant)

• Glutaradehyde product

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Liquid Sterilants:

• AKA “Cold Sterilants”• Destroys all microorganisms IF exposed long enough to the sterilant • Disadvantage:

– Time consuming (10 – 16 hours)– No bacterial spore test available; May use a color monitor dip

stick to test the strength– Whenever new item is added, time is reset to ten hours– Toxic chemicals: glutaraldehyde;

• do not leave container uncovered

• Advantage:– No packaging; will not harm heat sensitive items

• Clean and dry everything before immersion; any water will dilute solution and lower effectiveness

• After cycle, must rinse with sterile water; dry with clean towels, and wrap in clean packaging

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Sterilization Monitoring

– Biological monitoring with spore tests:

Liquid Disinfectant Monitoring: color monitor dip stick

(not a spore test)

• Process indicators