It may be impossible to remove all bacteria from dental equipment

A few stories have appeared in articles in recent years where someone has gotten an infection at an oral surgeon or dentists office due to unsafe practices. See for example This has occurred when a lapse in following proper infection control practices has occurred.

However, even when proper protocols are being followed at dental offices it may still be possible to come down with an infection (although rare). This is supported by a new study in the Journal Water Research titled “Efficacy of dental unit waterlines disinfectants on a polymicrobial biofilm.” The study reveals that disinfectants recommended by companies that manufacture dental unit water lines don’t actually shift all the bacteria in the lines, which means the water lines are never completely clean.

The dental water lines are used by dentists to keep their dental equipment, which is always coming in contact with people’s mouths, clean. In the study by researchers from the Université de Poitiers in France they analyzed three disinfectants used by some European dentists to control biofilms in dental water lines: Calbenium®, Oxygenal 6® and Sterispray®. The researchers tested how well the disinfectants removed biofilms from dental water lines. If the disinfectants are not completely effective (which of three of them were found to not be) then patients and dentists can be exposed to microorganisms present in the water circulating inside dental units when dental procedures are happening. Dr. Cost one of the study authors states:

“What is most worrying is that none of the disinfectants could kill the amoebae, which means they are still dangerous to patients and dentists even after water lines have been sterilized.”

The researchers highlighted several approaches to prevention of biofilm formation in dental water lines: 1) use good quality water that isn’t contaminated, 2) use a disinfectant for prevention, and 3) avoid letting water stagnate.

There have been rare cases where someone has gotten Legionnaire’s disease from a contaminated dental water line. As such being aware of the problem and following prevention strategies is important.

Source: Damien Costa, Marion Girardot, Joanne Bertaux, Julien Verdon, Christine Imbert. Efficacy of dental unit waterlines disinfectants on a polymicrobial biofilm. Water Research, 2016; 91: 38.

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