The Economist: Chunqi Jiang, a physicist at the University of Southern California, Los Angeles, and her colleagues have come up with a way to kill bacterial infections that appear as a biofilm on the roots of teeth: use of a “cold” plasma torch.Plasmas are gases in which the molecules have been stripped of some or all of their electrons, to create positive ions. Cold plasmas can be made using high electrical voltages.The team report in Plasma Processes and Polymers that when their plasma plume was directed into the infected interiors of teeth, it succeeded in clearing up well-established infections completely. Related LinkNanosecond Pulsed Plasma Dental Probe