The process water in dental units is a potential source of infection for patients, dentists and practice staff alike. Dent-aDes® HygieneSysteme GmbH in the city of Weinsberg has developed a system based on a special hypochlorite solution that is non-toxic for humans and efficiently combats bacteria.
Modern dental chairs are highly complex treatment units that consist of the actual chair as well as a broad range of different instruments and a water-conducting system. The latter is not only used as rinse water for patients, but also supplies the instruments used by dentists and their staff with water by way of between nine and eleven individual waterlines. The water used by the individual dental units can therefore enter the patient’s mouth area in numerous ways. It goes without saying that dental treatments rely on the utmost hygiene. The water does not come directly from municipal water supplies with their fluctuating pressure levels and low temperatures, but is usually preheated to 28°C and runs through pressure-control pumps.
The process water potentially therefore contains a higher than normal number of bacteria. A possible reason might be the formation of biofilms on the inner surface of the water-conducting systems which might pollute the water as it flows past. In addition to the bacteria contained in the process water that might be a risk for patients, aerosol formation during dental treatment might also be a health risk for dentists and dental staff. In addition, bacteria from patients' mouths can also enter the process water, as Dr. Michael Saefkow, managing director of Dent-aDes® HygieneSysteme GmbH explains: “In order to ensure an optimal treatment process, dental drills can be slowed down. The water then stops flowing, resulting in negative pressure that might suck bacteria into the instrument and thus into the waterline tubes."
In order to counteract bacterial contamination of process water, Saefkow has developed an innovative system based on his many years of experience with hospital hygiene products – and on a Russian invention he came across. During his long career as an R&D manager, Saefkow, a biologist by training, was involved in the production of disinfectant hypochlorite solutions by way of diaphragm cells (diaphragm electrolysis). He used the same technology for the system with which he founded Dent-aDes® HygieneSysteme GmbH in May 2015. He has largely managed the product and company establishment process with his own input and resources. He also received support from the Baden-Württemberg government in the form of an “Innovation Voucher for Small and Medium Enterprises”.
Diaphragm cells have been widely used since the late 19th century for producing disinfectant sodium hypochlorite solutions from aqueous sodium chloride solutions, to name but one example. Diaphragm cells consist of two compartments, one with an anode and the other with a cathode, separated by a semipermeable diaphragm. The compartments are filled with sodium chloride solution. At the cathode, water is reduced to hydrogen, and oxygen and chlorine are produced at the anode. The two compartments need to be separated in order to prevent oxygene and chlorine from coming into contact with hydrogen, which would produce a highly explosive mixture.
In 1998, by pure chance Saefkow came across a Russian invention where the diaphragm electrolysis method had been further developed. The hypochlorite solution produced with the Russian method had a greater antimicrobial effect than would be expected due to the comparatively low quantity of hypochlorite used. Saefkow put this effect down to the excitation of the water molecules during the process. “The process leads to structural changes in the water matrix, i.e. the water molecules, which interact with each other due to their dipolarity. This leads to a change in the solvation properties, resulting in a greater and more rapid effect.” The ingenious thing about the method is that a solution with a greater microbial effect is only generated within rather narrow process parameters. “We discovered that this is due to both the salt content of the starting solutions and also the flow velocities. This is actually quite surprising, because electrolysis only takes nanoseconds. A one-percent variation in the individual process parameters causes the product to lose its usual effect,” says Saefkow.
Saefkow has now refined the method and adapted it to the requirements of process water used in dental systems, resulting in a stable, disinfectant product of drinking water quality. The microbial effectiveness of Dent-aDes® has since been demonstrated with quantitative suspension experiments and using Pseudomonas bacteria as test organisms.
“Even with a Dent-aDes® dilution of only one ppm free chlorine per litre, a contact time of no more than 30 seconds is perfectly long enough to reduce the microorganisms to the legally prescribed number. In addition, in drinking-water compliant concentrations, Dent-aDes® can eliminate a biofilm within one to two weeks, while the same concentration of ‘normal’ hypochlorite solution is ineffective,” says Saefkow, adding: “Dent-aDes® gradually loses its effect, so that 14 days after bottling, 30 seconds are no longer enough to kill all bacteria. However, over a period of four months, the solution will continue to exert the desired effect within a contact time of 60 seconds. This is still considerably better than the effect a ‘normal’ hypochlorite solution would achieve. The researchers are currently working with research groups at the Universities of Bayreuth and Dresden to find out why the solution is so stable.
Dent-aDes® is produced in cooperation with Io-Li-tec, a start-up company from Heilbronn that will also be in charge of sales and marketing. Dent-aDes® will be available from May 2016 onwards on a subscription basis only. Saefkow has chosen this supply method because he wants to ensure that dentists will always have sufficient amounts of the solution available. In order to make sure that the same amount is always used, Saefkow will provide subscribers with a dosage unit, also developed by Saefkow and his team. The dosage system has been optimised for the varying requirements of dental units. “The dosage unit consists of a sensor system, also developed in-company, which automatically checks whether the concentration of the active agent is still ok and Dent-aDes® is still working as it,” explains Saefkow. This is necessary because X-rays have been found to reduce the effectiveness of the solution, and Saefkow cannot exclude the product being X-rayed in transit, in airports for example, for control purposes.