Plasma Jets Could Replace Dental Drills 131
Hugh Pickens writes "The first electric dental drill was patented in 1875; modern drills grind the diseased portions of teeth away at up to 500,000 rpm. But dentists have been seeking less invasive ways of wiping out stubborn, tooth-decaying bacteria. Now Live Science reports that bacteria-killing jets of plasma could soon replace the drills used to treat cavities in our teeth. Researchers recently demonstrated that a small, blowtorch-like device emitting a relatively cool beam of purple plasma could eliminate oral bacteria in cavities, leaving more tooth structure intact than a drill does. To test how well 'cold' plasma jets (about 100F or 38C) sterilize tooth material, researchers took slices of dentin from extracted human molars, doused them with bacteria, and torched them with the plasma jet. An inspection via a scanning electron microscope of the damage done to the germs shows bacterial remnants had holes in their cell walls. When the plasma jet fires, it charges oxygen in the surrounding air, creating highly reactive molecules that can break down the bacteria's defenses. Researchers believe the technique could be available to general dentistry in three to five years."
Re:Home use? (Score:3, Informative)
Re:right... (Score:5, Informative)
Re:Hard coating? (Score:5, Informative)
It exists: Dental sealant [wikipedia.org]
Re:right... (Score:5, Informative)
Re:right... (Score:4, Informative)
This won't replace the drill. (Score:4, Informative)
The drill isn't just for killing the bacteria inside cavities (called "caries" by dentists). The drill is used to make an undercut hole large enough to get stuffed with filling material. In doing so, it removes not only the bacteria but also the food-material that the bacteria was growing on. A plasma jet won't do either of those things, so they would still need to use a drill.
Re:right... (Score:5, Informative)
Looks like yet another solution looking for a problem. The point of the drilling is to remove infected dentin and leave healthy dentin intact. When teeth decay it's a process in which bacteria are demineralizing and destroying the hard structures of the tooth. Simply killing the bacteria is not sufficient to restore the damaged structures; the damaged structures themselves must be removed, along with any undamaged structures that have been undermined by decay. Additionally, if disinfection were the only goal the decay would still need to be exposed via drilling in order to effect disinfection. As much as people hate the drills, they also provide tactile feedback as to the location of decay. Hard tissue lasers are extremely expensive relative to the drills and provide no such feedback. Visual inspection is often insufficient to determine the quality of the dentin which is why we are always poking with those sharp little explorers. Another issue is being able to determine whether or not the bacteria have all been killed. Leaving infected dentin behind means the decay will simple continue from that point. Removing all of the softened, infected dentin is necessary to prevent recurrence of decay. Incidentally, traditional dental amalgam fillings (mercury, silver and tin) are inherently somewhat antibacterial. The metal tends to inhibit bacterial growth providing a small measure of protection to recurrence. However preventative measures like good daily diet and hygiene (e.g. cutting out the sugar and brushing/flossing) is still the best means of preserving your teeth.
Other methods of disinfection have been tried and failed, hence "drill and fill" remains the most reliable method of restoration.
Re:right... (Score:5, Informative)
As a dentist, I can comment here with some degree of authority on the subject. If a tooth has cavitated, in other words, the surface has broken, the dentin part you speak of being disinfected is a mushy mess. Even if the plasma could "disinfect" this area, the tooth would be left with a spongy core, incapable of supporting the remaining hard structure of the tooth. One of the fundamental parts of preparing a tooth is to not leave any unsupported enamel. If "infected" dentin is left, albeit bacteria free, the chance for tooth fracture is great.
I do think that this technology would work in early caries removal, such as shallow lesions. Often you don't know how deep a carious lesion will go until you open things up and start excavating decay out. At some point you will have to use some sort of mechanical process to scoop the decayed material out, either a hand instrument or a slower speed bur.
Now if you are concerned about the trade-off between exposing the pulp (nerve) and needing a root canal, or leaving a thin layer of carious dentin, this plasma approach may be good. It has been shown in research that a small layer of decay left under the proper filling, can repair itself and if small enough no root canal therapy may be necessary. The plasma may help out in disinfecting this area and help out the repair process. But I digress...
Standards of what is a cavity (Score:5, Informative)
I recently went after many years, and the dentist found three. I was a little suspicious, and asked the dentist about it. He said yes, due to advanced digital x-rays, cavities are spotted earlier. The more important fact was that he said with newer filling techniques and material, it allows them to fill smaller cavities. The older fillings didn't "take" that well in teeth, and so dentists had to let cavities grow largert, so they could fill them successfully. So the up to date, modern dentist will probably find these "mini-cavities" and fill them before it becomes a giant cavity.
Why do this then? Well one of my older style fillings was in a tooth that was weak, which cracked in half, and I needed a root canal and crown. The newer mini-fillings will keep more of the tooth, preventing problems like that in the future.
Re:Standards of what is a cavity (Score:3, Informative)
Just because they say there is a cavity doesn't mean there is one. A younger dentist insisted I had three cavities that needed filling. No x-rays, just based on the pressure test (where they push down on your teeth with a probe), where the dentist pushed down much harder than standards from several other dentists.
I changed dentists. He used x-rays and the pressure test and concluded no cavities. I mentioned what the other dentist said and he said no, no evidence of even smaller cavities. Since I was a new patient to the new dentist, he did a full workup, not just a routine visit checkup. Several years later, still no evidence of these supposedly obvious cavities.
Unfortunately, such fraud does occur. I don't know how common it is, but I am now convinced the one dentist was trying to invent work to justify excessive personal spending (she talked a lot about how much she'd spent on her home lately). I've seen enough guides to say that one of the best defenses against such fraud is to ask to see the pictures.
No, I'm not a dentist, but one doesn't have to be a dentist to realize that sometimes, a professional will claim work needs to be done when there is no professional justification for that work. It happens in all fields. I'm suspicious of the "well, our standards and technology have improved" excuse. For some reason, the older the dentist, the more likely they are to be willing to show me pictures or justification of any advised work (dating all the way back to when I was a kid and advised to get braces).