DEN 113 Module 3 - Surface and Dental Water Asepsis

Precleaning Versus Disinfection

• Precleaning:

  • Definition: The process of removing organic materials such as blood and saliva that have contaminated a surface.

  • Execution: The first wipe that is used on a contaminated surface.

• Disinfection:

  • Definition: The process of reducing the number of disease-causing microorganisms on a surface that has been pre-cleaned.

  • Execution: This is the second wipe that is used to clean the contaminated surface.

• Personal Protective Equipment (PPE):

  • Recommendation: Always wear PPE when cleaning, due to the potential for chemical splash.

Precleaning Methods

• Methods for Precleaning:

  • Typical cleaning agents include soap and water (using sponges or paper towels), mostly done with disinfecting wipes that need to stay wet.

  • Different wipes must be used for different purposes — a specific wipe for pre-cleaning and a different wipe for disinfecting.

  • Cleaning methods can include:

  • Spray-wipe-spray method

  • Wipe-discard-wipe method

  • Important to check surface tolerance for various chemicals used.

• Kill Time:

  • Definition: The amount of time a surface must be exposed to the chemical to kill the intended microorganism.

Types of Surfaces

• Clinical Contact Surfaces:

  • Definition: Surfaces touched with gloved hands during patient care, which may become contaminated with blood, saliva, or other potentially infectious materials (OPIM).

  • Requirement: Must be treated after every patient.

• Housekeeping Surfaces:

  • Definition: Surfaces that do not come into contact with hands, instruments, or devices during dental procedures.

  • Examples: Walls, windows, and similar surfaces.

  • Requirement: Can be treated at the end of the day.

Disinfectants

Low Level Disinfectants

• Functionality:

  • Inactivates some bacteria and some viruses but does NOT kill tuberculosis (TB), which is harder to kill.

• Registration:

  • EPA registered as Hospital Grade (e.g., Lysol).

• Microorganisms Inactivated:

  • Kills Staphylococcus aureus, Salmonella, and Pseudomonas aeruginosa.

• Alcohol-free Quaternary Ammonium Compounds (Quats):

  • Characteristics: Low antimicrobial action, used on floors and walls, NOT tuberculocidal.

  • Recommendation: Not recommended by the American Dental Association (ADA) for use in dentistry.

  • Addition of Alcohol:

  • Effect: Reduces kill time to 1 minute and raises the disinfectant level from low to intermediate.

Intermediate Level Disinfectants

• Functionality:

  • Inactivate all forms of microorganisms but do NOT destroy spores.

• Registration:

  • EPA registered as Hospital Disinfectant with tuberculocidal action.

• Examples:

  • Chlorines, Iodophors, Synthetic phenols, Quaternary Ammonium Compounds with Alcohol.

Chlorine Compounds

• Sodium Hypochlorite (Bleach):

  • Classification: Intermediate disinfectant.

  • Dilution: Common household bleach used at a 1:10 dilution with water is NOT approved by the EPA for office use but may be used at home.

  • TB Kill Time for Dilute Bleach:

  • Required time: 10 minutes.

  • Brand Approved by EPA:

  • Dispatch (TB kill time: 2 minutes).

Chlorine Compound Advantages & Disadvantages

• Advantages:

  • Rapid acting.

  • Economical.

  • Broad spectrum of activity.

• Disadvantages:

  • Diluted solutions must be discarded daily.

  • Can be corrosive to surfaces and metal; may damage fabrics.

  • Inactivated by bioburden; requires pre-cleaning and disinfection.

Iodophors

• Brand Names:

  • Iodo-five, Biocide.

• Composition:

  • Mixture of alcohol and iodine.

• Characteristics:

  • Most non-corrosive product, user-friendly (color changes indicate loss of effectiveness).

  • Kill Time:

  • 5-10 minutes for effectiveness.

  • Relation of Strength:

  • A full-strength (undiluted) iodophor is less effective than a diluted iodophor.

Iodophor Advantages & Disadvantages

• Advantages:

  • Broad spectrum coverage.

  • Provides residual biocidal activity.

• Disadvantages:

  • Dilution critical for effectiveness.

  • May stain materials.

  • Requires daily preparation.

  • Inactivated by bioburden; requires pre-cleaning and disinfection.

  • Can be corrosive to metals; MUST be mixed with distilled water.

Synthetic Phenols

• Brand Names:

  • Birex, Asepti-phene, Lysol IC.

• Composition:

  • Synthetic compounds related to carbolic acid.

• Characteristics:

  • EPA registered Hospital Disinfectant with tuberculocidal action.

  • May contain several different phenolic compounds.

  • Used in mouthwashes and hand-washing agents.

  • TB Kill Time:

  • 10 minutes.

Synthetic Phenols Advantages & Disadvantages

• Advantages:

  • Broad spectrum activity.

  • Residual biocidal activity.

  • Useful on metal, glass, and rubber surfaces.

• Disadvantages:

  • Must prepare fresh daily if diluted.

  • May leave a film after use.

  • Corrosive/damaging to some plastics.

Quaternary Ammonium Compounds with Alcohol

• Action Level:

  • Intermediate-level disinfectant.

• Effectiveness:

  • Tuberculocidal, kills TB within 1 minute.

• Products:

  • BIREX, Quat Dental Office Confectant Wipe, 10 Second Surface Sanitizer.

Disinfectants: High Level

• Functionality:

  • Inactivate bacteria, fungi, viruses, and some spores.

• Registration:

  • EPA registered as a sterilant or disinfectant based on time in the solution.

• Example:

  • Glutaraldehyde.

Glutaraldehyde (Gluts)

• Brand Names:

  • Procide, Cidex, Banicide, Sterall.

• Usage:

  • Used for immersion ONLY.

  • Items must be soaked for 6-10 hours to achieve sterilization.

Glutaraldehyde Advantages & Disadvantages

• Advantages:

  • Broad spectrum effectiveness.

  • Acts as a liquid sterilant for items that cannot be heat processed.

• Disadvantages:

  • Caustic to skin and eyes, has an unpleasant odor.

  • Limited use; items must be immersed (not for spraying or wiping).

  • Required immersion time of 6-10 hours.

Disinfectants: Stability

• Shelf-life:

  • The length of time the unopened container remains active (check date on package/container).

• Use-life:

  • The length of time solution remains active once it has been activated/mixed but not used.

  • Example: Glutaraldehyde may have a shelf-life of 2 years from the manufacturer but only 28 days once activated.

Tuberculosis (TB)

• Importance:

  • TB kill rate is the benchmark used for evaluating levels of disinfectants.

• Characteristics of TB:

  • TB is among the most difficult bacteria to inactivate.

  • Effective inactivation of TB indicates that the disinfectant will likely be effective against most other microorganisms.

Alcohols

• Types:

  • Isopropyl and ethyl alcohol.

• Application Recommendations:

  • Okay for use on hands for hand hygiene, but not recommended for use on surfaces as a precleaner or disinfectant.

  • Alcohol is added into cleaning products for effectiveness.

• Evaporation Time:

  • Alcohol has a rapid evaporation time, making it unsuitable for surface disinfection due to quick drying.

Disinfectants Versus Surface Covers

• Disinfectants Characteristics:

  • Few items needed.

  • Inexpensive to use.

  • Maintains aesthetic appearance of the office environment.

  • Environmentally friendly.

• Surface Covers/Barriers Characteristics:

  • Faster application time.

  • 100% effectiveness if used properly.

  • No need to clean underneath if used correctly.

  • Safer for equipment usage.

  • Adds waste to the environment; single-use products result in increased waste generation.

Surface Covers/Barriers

• Functions:

  • Prevent contamination of surfaces.

  • Liquids must not penetrate these covers.

• Materials Used:

  • Clear plastic wraps, bags, tubes, or plastic-backed paper are common materials.

• Design:

  • Various shapes and sizes, must conform to the surface being covered.

Application of Surface Covers/Barriers

• Procedural Steps:

  • Pre-clean and disinfect the surface before application.

  • Wash and dry hands before placing covers.

  • During cleanup, gloves should be worn.

  • Barriers must be disposed of in garbage after use.

  • If a surface is touched, it must be pre-cleaned and disinfected before replacing the barrier.

Radiographic & Laboratory Asepsis

• Equipment:

  • High-tech equipment should be covered with a plastic barrier to avoid contamination.

  • Perform hand hygiene prior to using keyboards and mice.

  • Use antimicrobial keyboards or plastic barriers to maintain hygiene.

  • Items that are not disposable require cleaning or sterilization (e.g., lathe).

  • Products sent to a dental lab need to be disinfected.

Dental Unit Water Asepsis

• EPA Standards:

  • The standard for drinking water is termed as "potable water," containing should have less than 500 CFU/mL.

  • Dental units sometimes report levels as high as 1.2-10 million CFU/mL.

• Microorganisms of Concern:

  • Pseudomonas, Legionella, Mycobacterium, and other bacteria.

Bacteria: Legionella

• Characteristics:

  • It is a Gram-negative bacterium commonly found in water sources (larger sources include hotels, spas, and cooling systems).

• Case Studies:

  • No cases in the U.S. originated from dental offices; however, a woman in Italy died in 2011 due to Legionella infection.

  • Documented 16 cases during a prison outbreak in the U.S. in 2020 and 13 cases in Elmira, NY in 2019.

Water Line CDC Recommendations

• Recommendations:

  • Use water that meets EPA standards.

  • Consult with dental unit manufacturers for appropriate maintenance.

  • Regularly monitor water quality.

  • Discharge water and air from handpieces and ultrasonic scalers for at least 1-2 minutes at the beginning of the day and 20-30 seconds in between patients.

  • Perform air purges at the end of the day.

  • Surgical procedures require sterile water.

  • If water exceeds 500 CFU/mL, need to shock the system.

  • Flushing lines does not remove biofilm.

Dental Unit Water Infection Control

• Flushing Mechanism:

  • The flush button on the back of the unit discharges all lines simultaneously.

• Patient Protection:

  • Use a rubber dam to protect patients from dental unit water and minimize aerosolizing and spattering of microorganisms.

• Water Reservoirs:

  • Use independent water reservoirs whenever possible.

• Avoid Backflow:

  • Do NOT allow patients to close around the saliva ejector, as backflow can introduce saliva and microorganisms into the water lines.

• Anti-retraction Valves:

  • Ensure all water lines have anti-retraction valves to prevent patient saliva and microorganisms from being pulled back into water lines and handpieces.

Water Quality Control: Boil Water Notice

• Situation:

  • Occurred in contaminated drinking water situations (e.g., Flint, MI).

• Recommendations:

  • When health officials issue a boil water notice, the water must be boiled prior to use.

  • If dental units have self-contained water systems, they can see patients; otherwise, they cannot until the notice is lifted.

  • Flush the system for 5 minutes after the boil water notice has been lifted.

Biofilm Growth in Dental Unit Water Lines (DUWL)

• Tubing Cross Section:

  • Influences flow rates; biofilm growth is affected by flow speed (fast flow vs. slow flow).

• Growth Rate:

  • Fastest flow reduces biofilm accumulation; slow flow and nearly no flow promote biofilm growth.

Time-lapse Growth of Biofilm

• Observation Techniques:

  • Documenting the development of biofilm over time in water lines.

Aseptic Techniques

• Procedures include:

  • Correct donning and doffing of PPE (Personal Protective Equipment).

  • Minimization of aerosols using high-volume evacuators (HVE) and saliva ejectors.

  • Utilization of dental dams.

  • Implementation of pre-procedural mouth rinses.

  • Use of disposable items to avoid cross-contamination.

  • Laundering contaminated clothing.

  • Aseptic retrieval of instruments and materials during procedures.