Dental school to investigate months-long use of tainted water lines

The faculty of dentistry at the University of Hong Kong has set up a taskforce to investigate an incident in which dental chairs whose attached water hoses became contaminated with bacteria were still used for patients.


The South China Morning Post learned of the investigation through an internal document, which says the taskforce will investigate the "causes and issues" of the incident and provide recommendations to minimise risks of similar mishaps.

It will interview staff involved in managing the crisis, including the manager of clinic 3A at the Prince Philip Dental Hospital in Sai Ying Pun, where the problem happened.

But one lawmaker questioned the independence of the investigation. The taskforce will be led by the hospital's new director, Thomas Flemmig, who came in after the incident. It will include an associate professor, Dr Michael Botelho, who is on the dentistry faculty, and Dr Vincent Cheng, an infection control specialist on the medical faculty.

"The investigation will not address the public worries unless it is led by an independent person," said lawmaker Kwok Ka-ki, who is also a medical practitioner. He said the university administration, not the medical or dental faculty, should lead it.

The investigation follows an incident exposed by the Post last week in which the dental hospital might have used "heavily contaminated" water to rinse patients' mouths from mid-February to mid-June.

The independent hospital, which is run by the university and governed by a board of government officials, said it had found "heavy biofilm contamination" inside tubing attached to dental chairs at clinic 3A. Biofilm happens when micro-organisms stick together on a surface.

But the hospital declined to disclose the level of bacteria recorded or how many patients were affected. And government officials have yet to comment on the incident.

One of the questions the taskforce will ask interviewees is why the clinic's manager did not temporarily halt the use of units with bacterial levels exceeding what is safe for drinking water until the problem was solved. The hospital's comptroller had proposed such a move.

According to an email sent to hospital staff in May, the comptroller said if the bacteria count was still unacceptable after cleaning, the hospital might need to replace all the connected tubes. "In such an unfortunate scenario, there may be a need to suspend all the dental units for use until the problem is solved," the comptroller wrote.

Another document showing the chronology of the incident reveals only six of the 57 chairs were eventually suspended from use.

Other questions to be asked include whether the manager had sought advice from the electrical and mechanical services department before using bleach to clean the tubes, why he did not consider using other more effective disinfecting solutions and why water samples were not sent to an accredited lab for analysis.

The document also revealed that the hospital still used the bleach in late June, after it obtained an effective disinfecting solution from Finland. It says the corrosive bleach might be destructive to the dental units.

Homer Tso Wei-kwok, chairman of the Dental Council, said all hospitals should have a protocol for crisis management. He said the hospital's board should be answerable to the public, as the hospital is outside the council's jurisdiction.

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