Dental decontamination in pictures

Figure 1: Transport box (dirty)
Contaminated instruments must be transported safely to the decontamination area (LDU). The box pictured is the correct type of box – secure lid, easily cleanable, with a carrying handle. The box should contain some water or a cleaning solution such as an enzymatic cleaner to keep the instruments wet, as it more difficult to clean instruments with dried blood and protein on the surface.

Figure 2: Inside transport box
The box illustrated has a tray inside, in which the instruments are placed. Puncture-resistant/heavy-duty gloves should be used when removing the tray of instruments. The instruments should then be rinsed (in the dirty sink if two sinks are present) and placed in an ultrasonic cleaner or loaded into a washer-disinfector. Handwashing of instruments should be carried out if necessary after mechanical cleaning of instruments either in an ultrasonic cleaner and/or washer-disinfector.

Figure 3: Personal protective equipment (PPE)
This picture shows appropriate PPE for use in the LDU, which includes mask, visor/protective glasses, gown and gloves.

Figure 4: Ultrasonic cleaner (COP para 3.2.4.2)
This is a small bench top ultrasonic cleaner. Use according to manufacturer’s advice and an annual validation should be carried out. Service as advised. Fill with enzymatic cleaner and turn on for a few minutes to degas. Set the temperature as advised by the manufacturer to suit the solution used.

Figure 5: Inside ultrasonic cleaner
Instruments transported into the LDU should be transferred from the dirty box to the ultrasonic tray (as in Figure 4), rinsed, and then the tray should be replaced in the ultrasonic cleaner. After cleaning, the instruments should be removed.

Figure 6: Sink
The sink pictured is the type of sink recommended for cleaning/rinsing instruments. There is a wrist-operated tap, the plughole is not under the tap spout and there is no overflow. There is also a separate tap (optional) in this sink. This delivers reverse osmosis water, which can be used for rinsing instruments after cleaning in the ultrasonic cleaner. In some LDUs, if there is space, two sinks can be installed – one for rinsing/washing dirty instruments (dirty sink), and a second sink for rinsing the cleaned instruments (clean sink).

Figure 7: Washer-disinfector (COP para 3.2.4.1)
Whenever possible, a washer-disinfector should be used to clean the instruments, as this is the most effective means of cleaning, and also disinfects the instruments (e.g., final rinse at 90˚C for one minute). This renders the instruments safer to handle after cleaning. Washer-disinfectors must be commissioned and validated annually or as advised by the manufacturer.
Periodic testing by the operator is also advised:
daily tests – spray arm rotations, spray nozzles, remove and clean strainers and filters as advised by manufacturer; and,
weekly tests – soil or other cleaning efficiency test.

Figure 8: Inside the washer-disinfector
If there is a washer-disinfector in the LDU, then after bringing the instruments from the surgery in the transport box (Figures 1 and 2), load the instruments into the washer-disinfector using the baskets and stands, with sharp ends pointing down, and forceps and other hinged instruments open. Handpieces should be attached to lumen cleaners in the washer-disinfector. Choose the cycle most appropriate to the load (follow the manufacturer’s instructions) and remove clean, dry instruments after the cycle.

Figure 9: Inspection light (task light)
After cleaning (ultrasonic or washer-disinfector), inspect the instruments under a bright light such as the one pictured here. Any instruments that are not clean should be put through the cleaning process again. Cement or other material adhering to instruments can be safely removed at this stage. Dry, clean instruments can be packed at this stage. The cycle number of the autoclave and the date of sterilisation should be recorded on the pouch/pack.

Figure 10: Autoclave
Pictured here is a B cycle autoclave (COP 3.2.5.1). Other types of autoclave cycles are S cycle (COP 3.2.5.2) or N cycle (COP 3.2.5.3). N cycle autoclaves are only used for sterilising unwrapped instruments for immediate use. All autoclaves must be commissioned, periodically tested and annually validated.

Figure 11: Inside the autoclave
It is important that the autoclave is properly loaded. Pouches must be window facing tray and must not overlap. De-ionised, sterile, distilled or reverse osmosis water should be used in autoclaves – town water must not be used (see manufacturer’s instructions). The cycle record must be read after each cycle to ensure that the cycle passed.

Figure 12: S cycle autoclave for handpieces and instruments
The autoclave in the picture is designed for sterilising handpieces or a small number of instruments. A device such as this can also be used in combination with an N cycle autoclave, as an N cycle does not sterilise lumens in handpieces.

Figure 13: Clean transport box
A clean transport box can be used to transport sterile instruments for storage. All instruments must be stored in a clean and dry drawer or other enclosed space. They can be stored, if necessary, in the LDU on the clean side or, if there are two rooms in the LDU, in the clean room. Unwrapped instruments must be used on the day of sterilisation. Storage of unwrapped instruments is not allowed. Storage of wrapped instruments for up to a year is permitted under clean and dry conditions.