Evaluation of the PotoClean(®) decontamination technology for reprocessing of water supply lines in dental units during routine work.

Background: A frequent problem in dental units is the microbial contamination of water and biofilm formation in the water supply lines. After random identification of a bacterial contaminated dental unit (310 cfu/ml) in a practise with 3 dental units we implemented the present study to evaluate the efficacy of the PotoClean(®) technology, based on anodic oxidation.

Method: The efficacy of a regular low concentrated permanent decontamination (1 mg Cl/L) with an additional intensive decontamination by PotoClean(®) (three times 20 mg Cl/ml for 2 h) on three dental units was tested over 7 months. Microbial contamination, total chlorine concentration and redox potential have been analyzed. Dental unit A and B was 15 years old, unit C 5 years.

Results: After 3 intensive decontaminations, in dental unit A and B the number of bacteria and moulds could be reduced less than 7 d. Thereafter the bacteria counts increased again during the subsequent 7 month period and the amount of moulds was with some exceptions 300 cfu/ml, although PotoClean(®) was constantly added in the system (1 mg Cl/L). After further 7.5 month only with low concentrated permanent disinfection (1 mg Cl/L) both units were successful decontaminated. Dental unit C represented an object which was easier to decontaminate because of the advanced construction (prevention of water stagnation) and the shorter useful life. At the beginning of the decontamination it was no bacterial contamination, but moulds were contained (300 cfu/ml). Already after the first intensive decontamination, no further bacteria and moulds could be detected.

Discussion: An important factor for the efficacy of PotoClean(®) was the age of the units and their construction. For a new generation of dental units PotoClean(®) was effective during the whole period of monitoring. For two old types of dental unit with massive biofilm development the successful decontamination needed more than 7 month.

Conclusion: The PotoClean(®) technology has resulted in even old-type turbines with intensive biofilm formation to complete decontamination. In a recent turbine design already after the first intensive decontamination with PotoClean(®) and its continuous use (1 mg Cl/L) no more contamination by bacteria and moulds were detectable.