Freezing preservation of the plasma treated water for disinfection treatment in dental and surgical therapies based on the reduced pH method

It has been demonstrated that atmospheric plasmajets can be used for non-conventional plasma processing that involves liquids. For the purpose of disinfecting human bodies in dental and surgical therapies, sterilization experiments in solution have been conducted with low-temperature atmospheric-pressure plasmas. For the plasma disinfection in the body fluid, we have successfully developed the reduced pH method that strong bactericidal activity can be achieved when the solution is sufficiently acidic. In addition, the plasma treated water (PTW) has been found to have strong bactericidal activity for a few minutes at room temperature. Its half lifetime depends on temperature and lower temperature brings longer lifetime. By freezing PTW, it is possible to preserve bactericidal activity for a month at least. We think that the disinfection by unfreezing PTW is a novel method of plasma disinfection. This type of indirect plasma exposure would bring safety plasma disinfection, because the selected supply of active species is possible.