1. Principles and Techniques of Disinfection
Chapter 20
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2. Chapter 20
Lesson 20.1
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3. Learning Objectives Pronounce, define, and spell the Key Terms.
Explain why surfaces in dental treatment rooms need barriers or disinfection.
Describe the guidelines of the Centers for Disease Control and Prevention for the disinfection of clinical contact surfaces.
Describe the two methods used to deal with surface contamination.
(Cont’d)
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4. Learning Objectives
(Cont’d)
List the types of surfaces in the dental office that are typically covered with barriers.
Explain the difference between disinfection and sterilization.
Explain the difference between a disinfectant and an antiseptic.
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5. Introduction
During patient treatment, surfaces in equipment and treatment rooms are likely to become contaminated with saliva or by aerosol containing blood, saliva, or both.
Laboratory studies have shown that microorganisms may survive on environmental surfaces for varying periods.
Assume that if a surface has had contact with saliva, blood, or other potentially infectious materials, it contains live microorganisms.
What is one of the most difficult microorganisms to kill? (Mycobacterium tuberculosis.)
How can exposure to microorganisms that survive on surfaces for long periods of time be reduced?
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6. Environmental Infection Control
The Centers for Disease Control and Prevention (CDC) Guidelines for Infection Control in Dental Health-Care Settings 2003 divide environmental surfaces into clinical-contact surfaces and housekeeping surfaces.
Housekeeping surfaces include floors, walls, and sinks. Because they have a much lower risk of disease transmission, cleaning and decontamination is not as rigorous as that for clinical areas and patient-treatment items.
Cleaning and decontaminating fabric used in carpet, drapes, and chairs is practically impossible without damaging the materials.
What is a logical alternative to disinfecting these challenging housekeeping surfaces? (Eliminating them from the clinical area.)
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7. Things to Consider When Cleaning and Disinfecting Patient-Treatment Areas
Amount of direct patient contact
Type and frequency of hand contact
Potential amount of contamination by aerosol and spray
Other sources of microorganisms (e.g., dust, soil, and water)
Start cleaning and disinfecting the most contaminated areas first, then move toward the least contaminated surfaces. Why is this the best sequence for disinfecting treatment areas?
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8. Clinical-Contact Surfaces
Clinical-contact surfaces can be directly contaminated either by spray or spatter generated during dental procedures or by contact with the dental professional’s gloved hands.
Current infection-control guidelines of the Office Safety and Asepsis Procedures Research Foundation (OSAP) recommend that clinical surfaces be classified and maintained under three categories:
Touch
Transfer
Splash, spatter, and droplet
What are the two divisions of environmental surfaces, according to the 2003 CDC guidelines? (Clinical-contact surfaces and housekeeping surfaces.)
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9. Types of Clinical Contact Surfaces
Touch surfaces are directly touched and contaminated during treatment procedures. They include the handles of dental lights, the controls of dental units, chair switches, chairside computers, pens, telephones, containers of dental materials, and drawer handles.
Transfer surfaces are not directly touched but often are touched with contaminated instruments. Transfer surfaces include instrument trays and handpiece holders.
Splash, spatter, and droplet surfaces do not actually come into contact with the members of the dental team or the contaminated instruments or supplies. Countertops are a major example.
Of these three categories, which area should be cleaned and disinfected first?
Touch surfaces are directly touched and contaminated during treatment; they should be barrier-protected or disinfected between patients.
Transfer surfaces are not directly touched but often are touched by contaminated instruments.
Splash, spatter, and droplet surfaces do not come into direct contact with members of the dental team or contaminated instruments; they should be cleaned at least once daily.
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10. Fig. 20-1 A, Touch surfaces. B, Transfer surfaces
Fig A, Touch surfaces. B, Transfer surfaces. C, Splash, spatter, and droplet surfaces.
This photo depicts the three categories:
A areas: Touch surfaces are directly touched and contaminated.
B areas: Transfer surfaces are not directly touched but may be touched with contaminated instruments.
C areas: Splash, spatter, and droplet surfaces do not actually come into contact with contaminated instruments or supplies.
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11. Managing Surface Contamination
There are two methods of dealing with surface contamination:
Barriers
Precleaning and disinfecting surfaces between patients
Most dental offices and clinics use a combination of precleaning and disinfecting surfaces along with the use of barriers.
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12. Types of Surface Barriers
A wide variety of surface barriers are available on the market today.
All should be resistant to fluids to keep microorganisms in saliva, blood, or other liquids from soaking through to the surface underneath.
Some plastic bags are designed in the shape of items such as the dental chair, air-water syringe, hoses, pens, and light handles.
Plastic-barrier tape is frequently used to protect smooth surfaces such as touch pads on equipment, electrical switches on chairs, and x-ray equipment. Aluminum foil can also be used because it is easily formed around any shape.
When removing contaminated barriers, avoid touching a contaminated clean surface underneath the barrier.
If a clean surface is inadvertently touched, the surface should be cleaned and disinfected.
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13. Fig. 20-3 An example of water on a fluid-resistant material
Fig An example of water on a fluid-resistant material. (Courtesy of Crosstex.)
Fluid, blood, and saliva should bead up on a fluid-resistant barrier.
It should look like a freshly waxed car on a rainy day.
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14. Fig Surfaces touched during patient care should be covered with protective barriers. If not protected, they must be cleaned and disinfected at the end of the procedure.
As you can see in this photo, barriers can be purchased in many shapes and sizes.
This variation helps ease application and removal and ensures a proper fit.
Well-fitting barriers reduce contamination of surfaces underneath the barriers.
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15. Fig. 20-5 Rolls of plastic tubing can be cut to the desired length
Fig Rolls of plastic tubing can be cut to the desired length. (Courtesy of Certol.)
Barriers can be dispensed in convenient boxes for easy access in treatment areas.
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16. Fig. 20-6 Tube socks provide barrier protection for difficult-to-clean areas. (Courtesy of Certol.)
Because cords can be a variety of lengths and thicknesses, tube socks are convenient to cut to a custom length.
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17. Remember
If a surface cannot be easily and thoroughly cleaned and disinfected, it should have barrier protection.
Using barriers can actually be more time-efficient and can create a safer environment than precleaning and disinfecting a surface.
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18. CDC Guidelines
If barriers are not used, surfaces should be cleaned and disinfected between patients with the use of an EPA-registered hospital disinfectant that is claimed to eradicate HIV and HBV.
Use PPE, as appropriate, when cleaning and disinfecting environmental surfaces.
Such equipment might include:
Gloves (e.g., puncture- and chemical-resistant utility)
Protective clothing
Protective eyewear/face shield and mask
Remember to spray disinfectant solution into a paper towel, rather than directly on hard surfaces, to avoid spreading chemical fumes.
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19. Precleaning and Disinfection
Precleaning means to clean before disinfecting.
All contaminated surfaces must be precleaned before they can be disinfected.
Even if there is no visible blood on a surface, it must be precleaned because even a thin layer of saliva on the surface can decrease the effectiveness of the disinfectant.
Precleaning reduces the number of microbes and removes blood and saliva (also called bioburden).
(Cont’d)
Even though no cases of cross-infection have been linked to surfaces in dental treatment rooms, the OSHA standard for bloodborne pathogens requires that contaminated work surfaces be disinfected between patient visits.
Precleaning is cleaning before disinfection: if a surface is not clean, it cannot be disinfected.
Regular soap and water can be used for precleaning.
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20. Precleaning and Disinfection
(Cont’d)
These techniques are most effective when used on contaminated surfaces that are smooth and easily accessible for cleaning.
Always wear utility gloves, mask, protective eyewear, and protective clothing when precleaning and disinfecting.
Surfaces that are irregular or textured are difficult or impossible to clean, thereby making them difficult to disinfect as well.
Regular soap and water may be used for precleaning, but it is more efficient if you select a disinfectant that can be used to clean as well as to disinfect.
If barriers are not used, or a combination of barriers and disinfecting is used to maintain surfaces, the surfaces should be cleaned and disinfected using an EPA-registered hospital disinfectant with HIV and HBV claim.
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21. The assistant shown here places clean wrap barriers on the handles of the operating light (Figure from Procedure 20-1).
Barriers can be placed with ungloved, washed hands.
In this photo the assistant is using barrier tape on the light handles.
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22. Disinfection
Disinfection is intended to kill disease-producing microorganisms that remain on the surface after precleaning.
Spores are not killed during disinfecting procedures.
Do not confuse disinfection with sterilization.
Sterilization is a process in which all forms of life are destroyed.
In autoclave sterilization, heat, pressure, and steam kill all forms of life.
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23. Disinfectants Versus Antiseptics
Disinfectants are chemicals that are applied to inanimate surfaces (e.g., countertops and dental equipment).
Antiseptics are antimicrobial agents that are applied to living tissue.
Disinfectants and antiseptics should never be used interchangeably because tissue toxicity and damage to equipment can result.
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24. Chapter 20
Lesson 20.2
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25. Learning Objectives
Name the government agency that is responsible for registering disinfectants.
Demonstrate the process of precleaning contaminated dental instruments.
Explain the precautions for the use of chemical sterilants/disinfectants.
(Cont’d)
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26. Learning Objectives
(Cont’d)
Identify chemical products used for intermediate and low-level surface disinfection and explain the advantages and disadvantages of each.
Demonstrate the process of cleaning and disinfecting a treatment room.
Describe the CDC guidelines for disinfecting housekeeping surfaces.
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27. Disinfectants
Disinfectants are chemicals that destroy or inactivate most species of pathogenic (disease-causing) microorganisms.
In dentistry, only those products that are EPA-registered hospital disinfectants with tuberculocidal (kills the tuberculosis bacteria) claims should be used to disinfect dental treatment areas.
Mycobacterium tuberculosis is highly resistant to disinfectants, and if a disinfectant will inactivate M. tuberculosis it will most certainly inactivate the less resistant microbial families (e.g., bacteria, viruses, and most fungi) on the treated surface.
Disinfectants are only effective if you follow the manufacturer’s guidelines for contact time.
Contact time is the amount of time the product must remain on the surface to destroy microorganisms.
Sporicidal means that product kills spores.
Virucidal means that a product kills some viruses.
Fungicidal means that a product kills fungi.
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28. The Perfect Disinfectant?
If there were an ideal surface disinfectant, it would rapidly kill a broad spectrum of bacteria, have residual activity and minimal toxicity, and would not damage the surfaces to be treated. In addition, it would be odorless and inexpensive, would work on surfaces with remaining bioburden, and would be simple to use.
Unfortunately, no single disinfectant product on the market today meets all these criteria.
When selecting a surface disinfectant, you must carefully consider the advantages and disadvantages of various products.
Often the manufacturers of dental equipment will recommend the type of surface disinfectant that is most appropriate for their dental chairs and units.
Disinfectant choice depends upon the type of equipment used in the office, plus any other criteria the staff would like to apply, such as a product that does not require daily mixing.
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29. Table 20-3 EPA-Registered Surface Disinfectants for Dentistry
This chart is very helpful in determining which one of the EPA-registered surface disinfectants will work best for a specific set of office criteria.
Note the contact time and the advantages and disadvantages of each product.
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30. Types of Chemical Surface Disinfectants
Iodophors are EPA-registered intermediate-level hospital disinfectants with tuberculocidal action.
Because iodophors contain iodine, they may corrode or discolor certain metals and may temporarily cause reddish or yellow stains on clothing and other surfaces.
Synthetic phenol compounds are EPA-registered intermediate-level hospital disinfectants with broad-spectrum disinfecting action.
Phenols can be used on metal, glass, rubber, or plastic. They may also be used as a holding solution for instruments; however, phenols leave a residual film on treated surfaces. Synthetic phenol compound is prepared daily.
(Cont’d)
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31. Fig. 20-9 Iodophor surface disinfectant. (Courtesy Certol.)
This iodophor comes in prepackaged individual doses for ease in daily preparation.
Typically the contents of the packet are placed in a spray container and water is added.
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32. Fig. 20-10 Synthetic phenol surface disinfectant. (Courtesy Certol.)
The larger gallon size allows one to measure the amount of disinfectant needed to pour into the spray bottle; then water is added.
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33. Types of Chemical Surface Disinfectants
(Cont’d)
Sodium hypochlorite (household bleach) is a fast-acting, economical, and broad-spectrum intermediate-level disinfectant (1:100 dilution for surface decontamination).
Bleach solution is unstable, must be prepared daily, has a strong odor, and is corrosive to some metals, destructive to fabrics, and irritating to the eyes and skin; it may eventually cause plastic chair covers to crack.
Alcohols are not effective in the presence of blood and saliva. They evaporate quickly and are damaging to certain materials such as plastics and vinyl.
The American Dental Association (ADA), CDC, and the Office of Safety and Asepsis Procedures Research Foundation (OSAP) do not recommend alcohol as an environmental surface disinfectant.
In the past, both of these chemicals were routinely used in the disinfection process.
We now know they are not the best products to select. Why?
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34. Fig Sodium hypochlorite (household bleach) is a disinfectant but is not EPA-registered and should not be used in dentistry as a surface disinfectant.
Bleach can be damaging to plastic tubing if it is used to control biofilm. It is best to use less harsh alternatives.
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35. Immersion Disinfectants
Some chemicals on the market can be used for sterilization or high-level disinfection.
When used as sterilants, they destroy all microbial life, including bacterial endospores. Depending on the type, time for sterilization can range from 6 hours to 30 hours.
At weaker dilutions or with shorter contact time, these chemicals provide high-level disinfection, which inactivates all microorganisms except endospores.
Most of these chemicals are toxic and can irritate the eyes, skin, and lungs. PPE must always be worn when these chemicals are used.
They are to be used for immersion (soaking) of heat-sensitive instruments and should never be used as surface disinfectants.
Always keep the lids of containers closed to minimize the fumes.
(Cont’d)
If there are instruments that cannot withstand the heat of autoclaving and no disposable instruments are available, immersion disinfectants can be used to sterilize the instruments.
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36. Immersion Disinfectants
(Cont’d)
Chlorine dioxide is an effective, rapid-acting environmental surface disinfectant (3 minutes) or chemical sterilant (6 hours).
Chlorine dioxide does not readily penetrate organic debris and must be used with a separate cleaner.
Chlorine dioxide must be prepared fresh daily, it must be used with good ventilation, and it is corrosive to aluminum containers.
It is important to maintain proper ventilation in a room in which immersion disinfectants are used.
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37. Fig. 20-12 Covered instrument tray for use with immersion disinfectants. (Courtesy of Certol.)
Clear plastic instrument trays with lids are necessary to reduce fumes and evaporation.
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38. Glutaraldehyde
Glutaraldehyde is classified as a high-level disinfectant/sterilant. It can also be used as a liquid sterilant when immersion time is greatly increased.
Glutaraldehyde products are useful for plastics and other items that cannot withstand heat sterilization.
Glutaraldehyde is very toxic and should be handled carefully to avoid the fumes.
Glutaraldehyde-treated instruments should never be used on patients without first being thoroughly rinsed with water.
Prolonged contact of certain types of instruments with glutaraldehyde solutions can lead to discoloration and corrosion of the instruments’ surfaces and cutting edges.
Many states no longer allow glutaraldehyde to be used in the dental office or clinic unless proper ventilation is installed, and others suggest eliminating its use completely.
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39. Ortho-Phthala-Dehyde Immersion Disinfectant
Ortho-phthala-dehyde (OPA) is classified as a high-level disinfectant.
OPA is effective in achieving high-level disinfection within 12 minutes at room temperature. It is more expensive than glutaraldehydes but may be a good alternative for individuals with a sensitivity to glutaraldehydes.
It has very little odor and does not require activation or mixing.
Some disadvantages of OPA: (1) It is costly, (2) it can be used only half as long as most glutaraldehydes in dentistry, (3) it may stain skin and fabrics, (4) plastics turn a blue-green color where proteins have not been removed, and (5) it would require more than 30 hours to secure sterilization.
All immersion disinfectants have disadvantages. Products that work best for the dental office should be selected, bearing in mind the amount of contact time needed and the type of ventilation available.
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40. Fig. 20-13 Fast-acting high-level disinfectant
Fig Fast-acting high-level disinfectant. (Courtesy of Crosstex International.)
This is a photo of a name-brand immersion disinfectant.
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41. Housekeeping Surfaces
There is no scientific evidence showing that housekeeping surfaces (e.g., floors,walls, and sinks) pose a risk for disease transmission in dental healthcare settings.
The majority of housekeeping surfaces need to be cleaned only with a detergent and water or an EPA-registered hospital disinfectant/detergent.
However, in the cleaning process, used solutions of detergents or disinfectants—especially if prepared in dirty containers, stored for long periods of time, or prepared incorrectly—may be reservoirs for microorganisms.
Make fresh cleaning solution each day; discard any remaining solution and let the container dry to minimize bacterial contamination.
When cleaning, try to avoid producing mists and aerosols or dispersing dust in patient-care areas.
To reduce aerosols, spray disinfectant directly into a paper towel.
Clean areas frequently to avoid dust buildup.
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42. Carpeting and Cloth Furnishings
Carpeting is more difficult to clean than is nonporous hard-surface flooring, and it cannot be reliably disinfected, especially after contamination with blood and other body substances.
Studies have documented the presence of bacteria and fungi in carpeting.
Cloth furnishings pose similar contamination risks in areas where there direct patient care is performed and where contaminated materials are handled, such as an operatory or instrument-processing area.
CDC guideline: Avoid using carpeting and cloth-upholstered furnishings in dental operatories, laboratories, and instrument-processing areas.
Any dental chair made of fabric should be covered with a large plastic barrier.
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43. Spills of Blood and Body Substances
The majority of blood contamination in dentistry results from spatter and the use of rotary or ultrasonic instruments.
No scientific evidence shows that HIV, HBV, or HCV has been transmitted from a housekeeping surface.
OSHA requires that blood spills and other body fluids be removed and the surfaces disinfected.
Always wear gloves and other PPE when decontaminating areas of spills.
CDC guideline: Clean spills of blood or other potentially infectious materials and decontaminate the surface with an EPA-registered hospital disinfectant with low-level (i.e., HBV and HIV label claims) to intermediate (i.e., tuberculocidal claims) activity, depending on the size of the spill and the surface porosity.
What type of gloves should be worn in the management of blood spills? (Utility.)
Reduce spatter by using suction constantly during the use of rotary or ultrasonic instruments.
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