Disinfection and Cleaning Flashcards
Outline the main stages of cleaning and disinfecting dental instruments?
- Cleaning
- Disinfection
- Inspection
- Packaging
- Sterilisation
What standards of cleaning and disinfection to all healthcare practitioners/equipment providers have to adhere to?
BS EN 285 and 13060 standards. SHTM 01 - 01D guidance used in reference to these standards.
What is meant by cleaning?
Removal of all biological matter from the surface of instruments.
Why is cleaning the first step in the process?
- To minimise spread of infection
- To achieve steam contact
- To ensure functionality of the instrument
- Legal requirement to do so
What is the primary method of cleaning instruments, and what back up options are there?
Washer-disinfector is the gold standard.
Ultrasonic bath is the secondary/back up method.
Manual cleaning should only be carried out if it is the only option.
What is meant by sterilisation?
Instruments should be put through a steam steriliser after being cleaned, so that little-no trace of microbial activity is found on the instrument before use on a new patient.
What is the main goal of the cleaning stage?
Removal of biological matter, in particular proteins/prions.
What three pieces of PPE should be worn during manual cleaning?
- An apron to protect the person
- A face shield to protect face and eyes from splashing
- Rubber gloves and heavy duty marigold gloves to protect hands.
Outline the process of manual cleaning.
- Dedicated sink for cleaning
- Fill with tap water at around 30-35 degrees Celsius
- Do not exceed 35, as proteins may coagulate making them harder to remove
- Chemical detergents added for manual cleaning specifically.
- Immersion/non-immersion cleaning
- Rinse in dedicated rinse sink
Why should scrubbing be performed under the water?
- Instruments in constant contact with water and detergent
- Lowers risk of splashing
- Lowers risk of aerosol production
What instrument should be used for immersion cleaning?
Long handled, soft bristled brush.
When should manual cleaning be performed?
- When it is specifically recommended by manufacturer’s instructions
- If there is no other alternative
-The automated processes have failed to remove the contamination.
What is the ultrasonic bath?
Ferocious process that uses sound-waves to remove contamination.
Why should a degas cycle be run on an ultrasonic?
To remove any gas/air bubbles that have built up in the machine whilst it has been out of use. Failure to do so reduces the effectiveness of the ultrasonic.
What temperature is the ultrasonic bath typically set to?
Between 20-30 degrees Celsius.
What type of water should be added to the ultrasonic?
Tap water is fine.
After either manual washing or ultrasonic, how should the instrument be processed?
- Rinsed in rinse sink
- Washer-disinfector
- Inspected
- Packaged
- Sterilised
What are the benefits of manual/ultrasonic washing?
- Greater force applied
- Some equipment manual wash only
- Ultrasonic baths good at removing contamination
What are the drawbacks of manual/ultrasonic washing?
- Member of staff required to be present
- Risk of aerosol production
- Risk of contaminating environment
- Human error
- Sharps injuries
- Potential to damage equipment
What are the main stages of an AWD, and what temperature do they reach?
- Flush/prewash - <35 degrees
- Main wash - depends on chemical
- Rinse <65 degrees
- Thermal disinfection - 90-95 degrees
- Drying - typically around 100 degrees
Describe the stages of an AWD.
- Flush/prewash - saturates contamination and removes gross debris
- Main wash - detergent used to effectively remove biological matter
- Rinse - removes biological/chemical residue
- Thermal disinfection - kills microorganisms with heated water.
- Drying - removes remaining moisture from surface of instruments.
Why is it key that proteins/prions be removed during the washing stage?
As they cannot be deactivated through disinfection or sterilisation, and higher temperatures can make them adhere to instruments.
What are the loading requirements of a washer disinfector?
- Available furniture must be used
- Clip trays must be positioned correctly
- No overlapping of equipment
- Hinged instruments must be open at hinge
- All assemblies should be disassembled before placing in AWD
What should be done if an instrument is still contaminated after an AWD cycle.
Ultrasonic/manually cleaned, followed by another AWD cycle.
Why is steam ideal for sterilisation?
- Steam carries massive amounts of energy
- Non-toxic
- Requires only water
- Only waste product is water
What type of water should be used for the sterilisation process?
Purified water (RO, de-ionised, distilled, sterile). This water has had organics, minerals, and micro-organisms removed from it.
What is a type-N steriliser?
Basic process of steriliser, often termed gravity displacement, or autoclave. Does not use a vacuum.
What are the drawbacks of using a type-N steriliser?
- Cycle isn’t entirely efficient
- Steam cannot penetrate instruments with pockets, channels, or lumens.
What temperature and pressure, and for how long do type-N and type-B sterilisers have to maintain for instruments to have been sterilised?
135-137 degrees Celsius
2.05-2.35 bar pressure
Minimum of three minutes