Plasma Brush: Better Alternative to Dental Fillings?

How does it work?
By creating a device that makes the tooth filling process pain-free—and the resulting filling more hard-wearing, the University of Missouri professors also hope to reduce the number and cost of replacement fillings.

When a dentist discovers cavities during a routine check-up, he often probes the surface of the tooth with a sharp instrument. A tooth is then filled by drilling out decayed pulp and replacing this with amalgam fillings made from metals or, more recently, from a composite of resin-based bisphenol A-glycidyl methacrylate (BISGMA) or urethane dimethacrylate (UDMA) and silica.

Often, probing does not cause pain except in the advanced stages of tooth decay, but conventional drills can cause “pain” because the vibrations from the drill trigger signals pain sensors in the tooth’s nerves.

But the University of Missouri inventors say the new device — the “non-thermal argon plasma brush” — is painless because it uses chemical reactions to disinfect and clean out cavities for filling, and does this in only 30 seconds.

It also doesn’t affect the teeth’s highly sensitive nerves, the plasma brush makers claim.

“The plasma brush fires out particles that carry a tiny electrical charge. These cut through the enamel to the middle of the tooth, instantly killing all bacteria they come into contact with,” the makers tell The Daily Mail.

The only hitch, according to Prof. Chen, is that while the procedure is painless and relatively quiet, dentists may still need to use a drill to assist in the filling process.

Stronger, longer-lasting fillings
Using current technologies, dental fillings can last up to ten years. But most people find that the wear and tear of daily eating causes the fillings to fall out sooner. What’s worse, a tooth can support only two to three fillings before it is too decayed, it has to be extracted.

In contrast, laboratory studies have shown the new plasma brush to create fillings that are 60 percent stronger, according to its inventors.

This is because the tiny electrical charges fired by the “plasma brush” also clear out the inside of the tooth more cleanly — allowing the dental filling to bond more strongly to the tooth.

Finally, the device uses a “cool flame” that strengthens the bond resulting in a longer-lasting filling that reduces the need to revisit the dentist to replace a lost filling, and the chance of losing a tooth from repeatedly filling replacements, as well.

Lower dental costs?
According to Prof. Hao Li, associate professor of mechanical and aerospace engineering at the MU College of Engineering and Prof. Chen’s colleague, the new “plasma brush” will be extremely useful for dentists because replacement fillings make up 75 percent of a dentist’s work.

The device will also lower dental costs. Right now, Prof. Li says, 200 million fillings cost Americans an estimated US$50 billion a year.

Commenting on the new device, Professor David Bartlett, head of prosthodontics at King’s College London Dental Institute, says: “In principle it sounds a good idea.”

“In order to access decay it is often necessary to drill through the enamel, which is the hardest material in the body,” he tells The Daily Mail. “If this mixture of gas and liquid can be shown to remove enamel it would be a big step forward for dentistry,” he says.

But he notes considerable upfront costs for dentists: “However, we know that conventional drills can get through the enamel and are relatively cheap devices — a few hundred pounds — whereas this new device is likely to be more expensive,” he adds.

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