The space-age device fires a beam of electrically charged oxygen atoms into tooth cavities to obliterate decay-causing bacteria.
Traditionally, the same job is done by drilling holes into the tooth that has to be filled. Unlike the drill, the plasma jet is non-invasive and pain-free.
Fear of fillings prevents many people from visiting the dentist.
A new study has shown that firing low-temperature plasma beams at dentine – the fibrous tooth structure below the enamel – can reduce bacteria levels by up to 10,000 times.
Researchers in Germany tested the effectiveness of the plasma jet against common dental bugs including Streptococcus mutans and Lactobacillus casei.
Lead researcher Dr Stefan Rupf, from Saarland University in Homburg, said: "
Drilling is a very uncomfortable and sometimes painful experience. Cold plasma, in contrast, is a contact-free method that is highly effective.
"A clinical treatment for dental cavities can be expected within three to five years."