Decommissioning of DUWLs
Section 19.10
In the absence of manufacturers’ guidance, DUWLs should be flushed, drained and left disconnected during any temporary closure of the treatment room. If this is not practicable, they should be flushed on a weekly basis as per the guidance above.
19.11
Self-contained water bottles (bottled water systems) should be removed, flushed with distilled or RO water and left open to the air for drying. They should then be stored inverted to prevent contamination during the temporary closure.
Recommissioning of DUWLs
Section 19.12
In the absence of manufacturers’ guidance, flush the DUWL for at least three minutes, disinfect the DUWL with a suitable disinfectant (as recommended by the manufacturer for routine disinfection of the DUWL), then flush for a further three minutes.
19.13 Where in-line filters are used, these will require treatment using a cleansing solution that has been recommended by the manufacturer. This step should be performed after first flushing the DUWL.
19.14 If DUWLs have disposable filters, they should be replaced.
19.15 Self-contained water bottles (bottled water systems) should be flushed with distilled or RO water. Where visual contamination is present, flushing with a suitable disinfectant followed by thorough washing is necessary. The manufacturer’s instructions will specify which disinfectant to use. In instances where visual contamination is routinely detected, it will be necessary to decrease the interval between flushing operations. If good practice is followed, practices should not routinely detect evidence of visual contamination.
19.16 As part of the recommissioning, dental equipment requiring protection against backflow should have the anti-retraction valves (incorporated on handpieces or waterlines) checked by the responsible person. They should ensure they are suitably decontaminated, refitted correctly and are operating in the correct manner.
6.79
Where monitoring is undertaken, the TVC should be expected to lie in the range 100 to 200 colony forming units per millilitre (cfu/ml).
In general, incubation should be at 22˚C. These measurements can be carried out by commercial microbiological services or by Public Health England. (Some commercial water-purification services offer microbiological control such that TVC values may be maintained below 10 cfu/ml.)
6.84
Where visual contamination is present, flushing with a suitable disinfectant followed by thorough washing is necessary.
6.86
Disinfection of DUWLs should be carried out periodically. In all cases, the manufacturer’s instructions should be consulted.
Sodium hypochlorite and isopropanol and a number of other agents have been shown to be effective in the removal of biofilm as well as the reduction of microbacterial contamination. However, these agents should only be used where recommended by manufacturers. If they are used, care should be taken to ensure that DUWLs are thoroughly flushed after disinfection and before being returned to clinical use.
