Only heat can kill HIV on dental tools.

By the Associated Press

A chemical disinfectant used on some medical and dental devices can fail to kill the AIDS virus, posing a potential risk of infecting patients, a study suggests.

Researchers found that in the laboratory, the disinfectant did not kill the AIDS virus in blood lodged in lubricants commonly used in dental equipment and in medical devices called endoscopes, which are inserted into the body to allow an interior view.

None of the devices has ever been shown to be the cause of HIV transmission from patient to patient, said researcher David Lewis, a microbiologist at the University of Georgia in Athens.

HIV survived in germ killer In the study, published by Lewis and another researcher in the September issue of the journal Nature Medicine, the AIDS virus survived after the contaminated lubricants were soaked for two hours in a powerful germ killer called glutaraldehyde.

Lewis said the study amphasizes the need to sterilize dental equipment at extremely high temperatures, as recommended by the federal government and the American Dental Association. He also said the standards for decontaminating endoscopes should be raised.

But Dr. David Fleisher, past president of the American Dental Association said current decontaminating procedurs are "extremely effective".

And, he said, the experiment failed to mimic all the steps of the decontamination procedure used on gastrointestinal endoscopes.

More than 90 percent of American dentists use heat sterilization, said Chris Martin, a spokesman for the American Dental Association.