Last week, as many as 72 patients at the National Dental Centre Singapore (NDCS) were treated with instruments that had not been fully sterilised.

Apologising for the slip-up, NDCS director Poon Choy Yoke said: "Patient safety and well-being are our first priority."

It was the right thing to say. But was it an accurate statement?

The problem is not that a batch of instruments had not been fully disinfected. Accidents can and do happen. What is shocking is that the discovery was made on June 5 afternoon, but the compromised packs continued to be used the following day.

If patient well-being was truly the "first priority", it would have been easy enough for NDCS to get a few people to work overtime on June 5 to identify and recall all the instruments that had not gone through the third step of sterilisation to destroy bacterial spores.

Alternatively, all the clinics could have been alerted to look out for packs that did not have the markings indicating complete sterilisation, and told not to use them. Instead, dentists continued to use some of the compromised packs on June 6.

Asked how many more patients were treated with the compromised equipment the following day, Dr Poon said she was "unable to ascertain how many of the 72 packs were used on each day".

Was the lack of rapid action because the NDCS deemed the risk of infection to be "extremely low", something it has said several times?

There is a reason these instruments, which are put into the mouth, go through a three-step sterilisation process. No matter how small, the risk exists, hence the requirement for three sterilisation steps.

People put their trust in doctors and dentists to take the best possible care of them. What happened at the NDCS did not pass this test.

The Ministry of Health has to ensure that healthcare institutions take their responsibilities more seriously.