On 12 June, the National Dental Centre Singapore (NDCS) reported that a total of 72 packs of dental instruments were not completely sterilised before being used in treatments last week on 5 and 6 June.

All the packs were used for dental treatment before they could be retrieved, although the risk of infection to patients has been assessed to be "extremely low" as earlier steps in the sterilisation process would have removed close to 100% of the organisms of concern, said NDCS.

NDCS said the instruments had undergone thermal washer disinfection, but had not completed the final step of steam sterilisation before being used at its specialist outpatient clinics on levels 2, 4 and 6 of the NDCS building.

NDCS is now contacting the 714 patients who were treated on 5 and 6 June after the discovery. 72 could have received treatment using the instruments.

Final sterilisation process was not conducted

The Ministry of Health (MOH) was informed on 9 June and a spokesman said, "MOH has directed SingHealth and NDCS to conduct a thorough review of the incident and the processes involved, and to report its findings and follow up actions to MOH."

MOH said it will review the report and determine if any regulatory actions should be taken against NDCS. The spokesman added that MOH's priority is the safety and wellbeing of patients.

NDCS has conducted a thorough review of the incident and has implemented additional controls to prevent any recurrence.

It also shared its three-step sterilisation process of its dental instruments, of which the first two remove and inactivate organisms, including viruses.

1. The instruments are thoroughly machine-washed to remove physical debris.
2. The instruments are thermally disinfected.
3. Finally, the instruments are put through an additional steam sterilisation for destruction of bacterial spores.

The final sterilisation that would remove bacterial spores – particularly Clostridium perfringens, which affects the gut, and Clostridium tetani, which causes tetanus – was not done.

NDCS issues apology and takes responsibility

The error was realised on 5 June as the packs lacked markings to show they had gone through full sterilisation. Some continued to be used the next day as "efforts were made to trace and recall all affected dental instruments" but not all were traced till the next day, according to the NCDS.

"Given the nature of treatment at the outpatient clinics and the completion of the earlier steps in the sterilisation process which would remove close to 100% of organisms of concern, the risk of infection to patients is assessed to be extremely low," the NDCS reassured.

NDCS director Poon Choy Yoke apologised over the incident and any anxiety caused, emphasising that patient safety and well-being are the top priorities of NDCS.

"We have taken immediate steps to strengthen our processes and ensure the safety of all patients in our care," she added. MIMS

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