AWD and Sterilisation Flashcards
Do you have to use the automatic washer disinfector?
Yes - it is a legal requirement to process contaminated instruments through it
Why is using the AWD the preferred method or cleaning dental instruments?
- it offers the best option for the control and reproducibility of cleaning and the cleaning process can be validated.
- It carries out the process of cleaning and disinfection consecutively
What are the steps in a typic WD cycle?
1 - Flush 2 - Wash 3 - Rinse 4 - Thermal disinfection 5 - Drying
Describe the flush step of the AWD. What should the water temp be and why?
- Removes ‘difficult’ gross contamination, including blood, tissue debris, bone fragments and other fluid and solid debris
- water temperature of <45°C is used to prevent protein coagulation and fixing of soil to the instrument.
Describe the wash step of the AWD. What must the detergents in this step used be?
- Removes any remaining soil
- Mechanical and chemical processes loosen and break up contamination adhering to the instrument surface
-The detergent must be specified by the manufacturer as suitable for use in a WD
Describe the rinsing stage of the AWD.
-Removes detergent used during the cleaning process. -this stage can contain several substages.
Describe the thermal disinfection stage of the AWD.
The temperature of the load is raised and held at the pre-set disinfection temperature for the required disinfection holding time: for example, 80˚C for 10 minutes, or 90˚C for 1 minute.
Describe the drying stage of the AWD
Purges the load and chamber with heated air to remove residual moisture.
What needs to be done after the instruments are processed through the AWD?
Need to be inspected to see if there is any visible contamination present
How are instruments inspected after going through the AWD?
Inspected using an illuminated magnifier
What should be done if visible contamination is identified upon examination after being processed through the AWD?
The instrument should be manually washed then put back in the washer disinfector (because need the thermal disinfection stage again)
After inspection (and no contamination present), what is the next step in the decontamination process?
Prepping equipment for sterilisation
Why is steam used in the sterilisation process?
We use steam in the sterilisation process as it:
• Carries a lot of energy
• Is non-toxic
• The main ingredient is water which is readily available
• There is no waste product except water
What kind of water needs to be used for the sterilisation process?
Purified water as all the particulate has been removed
How is pressure created from steam in small spaces?
The steam produced from water will be in excess of 1000x the water volume. This will create pressure in confined space and is good as only a small volume of water is required to fill up the chamber for sterilising
What are the 3 main types of sterilisers found in the dental environment?
- Type N
- Type B
- Type S
Describe the Type N Steriliser and how it works.
- The machine heats water in the chamber and as it turns to steam it passively forces the air from the chamber
- The process isnt entirely efficient and can leave pockets of air within the chamber
What instruments cant be processed in the Type N steriliser?
can’t process wrapped instruments or channelled or lumened instruments
Why are the possible air pockets left in the Type N steriliser a problem?
The problem with pockets of air is because air cannot be heated or maintain temperature like steam can (it is always at a lower temp than the surrounding steam). If any instruments are in contact with the air and not steam then it might not reach its sterilisation temperature for the minimum time required.
As the cycle in the type N steriliser isnt entirely efficient, it is only recommended to process what kinds of instruments?
‘rigid steel instrumentation with no pockets, channels or lumens’ and don’t process wrapped instrumentation
All 3 types of sterilisers need to reach what temperature and hold it for how long?
134-137 degrees Celsius and hold for a min of 3 mins
Describe how the Type B steriliser works.
- First step removes all the air from the chamber using a vacuum pump
- Then fills the chamber with steam
- Because the air has been removed, a vacuum (negative pressure) has been created which allows the steam to rush into the chamber
- This means that the steam effectively contacts all the surfaces of what is being processed
- Has a drying stage at the end to remove any remaining moisture
What instruments can be processed through the Type B Steriliser?
• Because of the vacuum, can process ‘wrapped, channelled and lumened instruments’. Can also process items such as cotton wool swabs.
What does a Type S steriliser process?
• It can only be used for the equipment it is designed to process and must follow manufacturer’s recommendations.
Specialised for handpieces ect
