Table 1

PDSA (Plan-Do-Study-Act) cycles summarising the process of disinfection and maintenance of DUWL

1To assess distilled water from its main source and the DUWL
  • Distilled water was tested after being dispensed through the dental unit (room 2)

  • The distilled water supply was then tested directly from the main source

  • The distilled water source showed bacterial counts within the acceptable range

  • The same water showed high bacterial counts once dispensed through the DUWL (table 2)

The source of contamination was identified as the contaminated DUWLs and not the source of distilled water
2To assess the effectiveness of the suggested disinfection protocol
  • ICX disinfection tablet was used in DUWL of room 2 every 15 days

  • Water from the dental unit was flushed for 2 min each morning and 30 s between patients

  • Bacterial counts reduced within 1 month of the disinfection protocol

    (table 3)

 The suggested disinfection protocol was effective for one dental unit
3To assess generalisability
  • The DAS briefed all the dental assistants on the disinfection protocol

  •  The remaining DUWLs showed reduced bacterial counts and compliance with the JCI standards (table 3)

The same disinfection protocol was effective on all the dental units
4To assess the sustainability and compliance of this protocol
  • Water was sampled 6 monthly, from each dental unit

  • A logbook accounting for daily flushing and shock treatment every 15 days was assigned to each assistant

  • At 6 months, the reduced bacterial counts were maintained (table 3)

  • All of the dental assistants complied to the suggested disinfection protocol

The suggested protocol was deemed sustainable. However, the cost-effectiveness of this protocol was identified as an area for further improvement
  • DAS, dental assistant supervisor; DUWL, dental unit waterline; QIC, quality improvement committee.