London, Jan 20 (IANS) Plasma jets capable of destroying tooth decay-causing bacteria could be an effective and less painful alternative to the dentist’s drill, says a new study.
Firing low temperature plasma beams at dentin - the fibrous tooth structure underneath the enamel coating - was found to reduce the amount of dental bacteria by up to 10,000-fold.

Plasmas are known as the fourth state of matter after solids, liquids and gases and have an increasing number of technical and medical applications. They are common everywhere in the cosmos, and are produced when high-energy processes strip atoms of one or more of their electrons.

Stefan Rupf from Saarland University, who led the research, said the recent development of cold plasmas that have temperatures of around 40 degrees Celsius showed great promise for use in dentistry.

“The low temperature means they can kill the microbes while preserving the tooth. The dental pulp at the centre of the tooth, underneath the dentin, is linked to the blood supply and nerves and heat damage to it must be avoided at all costs,” he said.

Scientists tested the effectiveness of plasma against common oral pathogens, including Streptococcus mutans and Lactobacillus casei.

These bacteria form films on teeth surface and are capable of eroding tooth enamel and the dentin below it to cause cavities. If left untreated it can lead to pain, tooth loss and sometimes severe gum infections.

In this study, the researchers infected dentin from extracted human molars with four strains of bacteria and then exposed it to plasma jets for 6, 12 or 18 seconds. The longer the dentin was exposed to the plasma, the greater the amount of bacteria that were eliminated.

This forms high-temperature reactive oxygen species that are capable of destroying microbes. These hot plasmas are already used to disinfect surgical instruments.

The findings were published in the February issue of the Journal of Medical Microbiology.