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Cavities: a thing of the past?


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The typical human mouth contains a writhing orgy of bacteria. Most of these microscopic organisms are benign, and some are even beneficial, but one particular variety is a conspicuous troublemaker: Streptococcus mutans. These ubiquitous bacteria thrive on sugars in the mouth, which they consume while excreting lactic acid. This acid is responsible for the great majority of tooth decay in humankind because it erodes the enamel and dentin of the teeth. A Florida-based company called Oragenics may have found a way to rid our mouths of these acid-excreting organisms for good. This would make cavities a thing of the past, and put no small number of dentists out of business. But despite the obvious benefits, there is potential for disaster.

 

Oragenics' approach to stopping tooth decay is straightforward: they have used recombinant DNA technology to produce a new variety of S. mutans which does not excrete lactic acid. Instead, it excretes tiny amounts of an agent called Mutacin 1140 which is deadly to other strains of S. mutans, giving these new bacteria an edge over the existing organisms. Once the modified bacteria get a toehold in the mouth, the existing population of S. mutans will be methodically wiped out, leaving the non-acid-producing bacteria in its place. In the absence of acid-producing bacteria, the teeth have little to fear. Oragenics calls this new treatment Replacement Therapy.

 

If approved as a treatment, a single visit to the dentist would be all that is necessary. The patient's teeth would be swabbed with the modified bacteria for five minutes, allowing it to begin its work. Over the following months, the entire population of the unmodified S. mutans in the mouth would be completely supplanted. The new organisms' ability to muscle out the old riffraff should theoretically allow the new bacteria to reside indefinitely once it is established in the mouth– so it is possible that a single treatment will last for an individual's lifetime.

 

On the surface it seems like an elegant solution, but clearly there is the potential to upset delicate systems in nature, resulting in possible larger-scale side effects. If S. mutans is present in the ecosystem outside of mouths, there is a chance that the artificial strains might be accidentally introduced into those systems, possibly destroying the natural strains. The acidity in those environments might then be drastically reduced, resulting in unpredictable and irreversible changes. This is a risk shared with many genetically modified organisms.

 

After extensive laboratory testing and animal trials with no observed side-effects, Oragenics has begun some early human trials. The first strains tested on humans have been deliberately crippled to require a daily "feeding" of a particular amino acid in order to survive. Using this method, researchers are confident that any of the bacteria which escape into the wild will not long survive. Also, the first people to be infected with the improved strain are denture wearers, which allows the subjects to remove their teeth at any time in case of trouble. The spouses of the subjects are also cooperating with the study, so researchers can reinforce their confidence that the bacteria is not horizontally transmissible, such as through kissing.

 

There is no doubt that eliminating cavities from humankind would improve our quality of life. But in a complex system such as the environment it is impossible to predict what will happen when a tiny segment of the ecosystem is replaced. Hopefully further research will provide a reliable ability to determine whether such concerns are valid, or whether they are merely the offspring of technology-stifling fear of the new and unfamiliar.

 

Thanks to Deetman on IRC for finding this. :)

 

source: http://www.damninteresting.com/?p=584

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Not much has happened since 2004, except the stock price has gone down to 86 cents.

http://www.usatoday.com/tech/news/biotech/...dentistry_x.htm

Posted 12/1/2004 4:24 AM

 

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Gen-mod dental treatment gets approval for human testing

By Wallace Witkowski, Associated Press

NEW YORK — A biotech company has won approval to conduct human trials of a dental treatment that uses genetically modified bacteria to prevent cavities for a lifetime, after resolving regulators' safety concerns.

 

Oragenics Inc. said Tuesday that trials of the product, known as Replacement Therapy, would get underway early next year. The company's shares surged 20% on the news.

 

The announcement comes roughly a year-and-a-half after the Food and Drug Administration put the Alachua, Fla.-based company's trials on hold pending modifications to better protect test subjects. The Oragenics' therapy replaces the bacteria that convert sugar to lactic acid, which causes cavities, with genetically modified bacteria that do not produce lactic acid. The company says the one-time application, which is swabbed directly onto the teeth, takes about a year to fully take effect.

 

The FDA, which declined to comment Tuesday, wanted to make sure Oragenics could quickly remove the genetically modified bacteria from a test subject's teeth should something go wrong, said Oragenics' president and chief executive Chuck Soponis. The agency was also concerned about the possibility the bacteria could be spread by kissing or other close contact.

 

"You have to appreciate that replacement therapy has never been done before; this is FDA's first impression of it," Soponis said.

 

In the safety study, Oragenics will use a strain of the genetically modified bacteria that requires a daily feeding of an amino acid that does not occur in the body in order to stay alive.

 

Another modification to the original trial plan is that participants in the clinical trial will be denture wearers, Soponis said. That way, if the bacteria need to be quickly eliminated for safety reasons, the dentures can be taken out of the mouth and soaked in bleach.

 

The Phase I safety trial will enroll 15 people along with their partners or spouses to test the communicability of the genetically modified bacteria.

 

"The FDA wanted people enrolled with their spouses or partners to see if the bacteria was horizontally transmissible," Soponis said. The company does not believe the bacteria can be spread from person to person.

 

If all goes well, the company will proceed onto further trials with a version of the bacteria that does not require the amino acid to survive, thereby providing the lifelong benefit. Eventually, people who have their own teeth will be enrolled to test the treatment's efficacy.

 

Soponis said he hopes to see Replacement Therapy on the market in the next four to five years.

 

In trading Tuesday, Oragenics shares closed up 62 cents, or 20%, at $3.79 on the American Stock Exchange. The biotechnology company's shares have traded in a 52-week range of $2.00 to $4.85.

Copyright 2005 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

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