Water filtration in dental units

As such water comes into contact with patients’ mucous membranes, for example during rinsing and cooling, dental practices and dental departments in clinics must ensure that the water used is germ-free and microbiologically safe in accordance with Section 23 of the German Infection Protection Act.

Furthermore, medical staff must also be protected against infections caused by contaminated aerosols.

Measures to prevent microbial contamination

In order to prevent microbial contamination in water-bearing systems of dental units, the KRINKO (Commission for Hospital Hygiene and Infection Prevention at the Robert Koch Institute) set out the following points, among others, in its 2006 recommendation “Infection prevention in dentistry – requirements for hygiene”:

• only water that meets the requirements of the German Drinking Water Ordinance may be supplied to dental units;
• only disinfection systems with proven effectiveness may be used;
• any existing biofilm colonization must be removed during retrofitting in order to restore the original condition;
• a well-maintained dental treatment unit shall not exceed a total bacterial load of 100 CFU/ml; for legionella, the internationally established guideline value of less than 1 CFU/ml should not be exceeded;
• microbiological testing of the water by an accredited laboratory is advisable every 12 months;
• any suspicion of a waterborne infection must be investigated;
• experts agree that water from dental facilities used to treat highly immunosuppressed patients must be free of pseudomonas, cryptosporidium and legionella.

Although this recommendation has no longer been included in the current KRINKO recommendations since the beginning of the year 2021, it continues to serve as a reference (according to the RKI) until updated scientific knowledge on the microbiological quality of water from dental units is available.

Criteria for assessing the microbiological quality of water from dental units are to be addressed in the future KRINKO recommendation “Hygienic examinations in medical facilities”, which is currently being prepared.

Media reports and studies – particularly from the USA – document a large number of cases in which children were infected with non-tuberculous mycobacteria – NTM for short – following dental procedures.

Non-tuberculous mycobacteria are environmental pathogens that can be found in water and thus also in dental treatment units. Children in particular are susceptible to NTM infections if they are exposed to contaminated water in dental facilities. This can result in serious infections of the lungs, lymph nodes, blood and skin. Such incidents emphasize the need for strict water hygiene measures in the use, maintenance and cleaning of dental units.

The use of disposable water filters can significantly reduce the risk of such infections by providing an effective barrier against NTM and other waterborne pathogens, thus ensuring the safety and health of patients and medical staff.