Biofilm problems

With the heightened emphasis on decontamination and cross infection control within dentistry over the past few years and the legislative demands for compliance with HTM 01-05, dental practices are increasingly aware of their obligations in regard to patient health and safety. One such long standing issue, certainly not exclusive to dentistry, is the problem of biofilm.

Biofilm, which can cause water quality to fall below the minimum standards required by HTM 01-05, is prevalent in dental unit water lines (DUWLs) because in the majority of today's most commonly used treatment centres, water is delivered via a tubing mechanism, providing an ideal environment for the development of bacterial biofilms. It is the biofilm itself that gives rise to problems in two key areas: the physical restriction of flow in narrow lumens; and in significant numbers of planktonic bacteria in the output water.

The term biofilm refers to a collection of microorganisms adhered to a surface and surrounded by a protective and adherent slime (known as the extracellular matrix) secreted by the bacteria. Biofilms are particularly prevalent where water with only low concentrations of solids and low levels of nutrients are found. As well as DUWLs, examples can be found in streams and rivers, cooling towers and piped water systems.