A simple plasma device for biomedical applications

Summary form only given. For root canal disinfection, the principal methods include mechanic cleaning, irrigation, laser irradiation, ultrasound, application of hypochlorite, and other anti-bacterial compounds. Clinic studies show that there are about 10% of treatment failures when the traditional disinfection methods are used. The failures are mainly due to the presence of bacteria, which can´t be completely sterilized by the methods mentioned above. One potential method to improve the disinfection performance is by using atmospheric pressure cold plasmas. It has been reported that atmospheric pressure cold plasmas can kill various types of bacteria, virus, and so on. However, due to the narrow channel shape geometry of a root canal, which typically has a length of few centimeters and a diameter of one millimeter or less, the effluent of a plasma plume generated by a plasma jet device is not efficient to deliver reactive agents into the root canal for disinfection. Therefore, to have a better killing efficacy, a plasma has too be generated inside the root canal. In this paper, a reliable and user-friendly plasma jet device, which can generate plasma inside the root canal, is reported. The plasma can be touched by bare hands and can be directed manually by a user to place it into root canal for disinfection without causing any painful sensation. When He/O (20%) is used as working gas, the rotational and vibrational temperatures of the plasma are about 300 K and 2700 K, respectively. The peak discharge current is about 10 mA. Preliminary inactivation experiment results show that it can efficiently kill Enterococcus faecalis, one of the main types of bacterium causing failure of root canal treatment in several minutes.