The End of Tooth Decay as We Know It
Within the next four to five years, a new mouth rinse may provide lifetime cavity protection, quite possibly with a single application in infancy. Dr. Jeffrey Hillman, professor of oral microbiology at the University of Florida at Gainesville, recently announced successful results in laboratory rats, after twenty years of research. The new anti-decay vaccine will undergo a series of clnical trials to determine efficacy and safety, lasting two to three years and involving thousands of human subjects. The vaccine, involving a genetically altered variant of the normal "tooth decay" bacterium, represents a new technology that may eventually be applied to the treatment of disease and infection without antibiotics.
The naturally occurring tooth-decay germ, Streptococcus mutans, evolved along with humans over hundreds of thousands of years. Over that span of time, the bacterium came into balance with its host (that's us!) so that it caused no harm. The introduction of refined sugars into our diet, relatively recent in evolutionary terms, upset that balance. Streptococcus mutans lives on the sugar residue on people's teeth, and produces lactic acid as a waste product.? The lactic acid eats away at tooth enamel, causing cavities. (This does suggest that more frequent brushing and fewer sweets could make make visits to the dentist a more unusual event!)
The new mouth rinse treatment contains a genetically modified version of the Streptococcus mutans. Dr. Hillman's modified bacterium does not produce acid, and so does not cause decay. Once introduced into the mouth, it will replace the naturally occurring bacterium, greatly reducing the likelihood of decay. ? According to Dr. Hillman, the treatment will probably cost less than $100 and may last a lifetime, an obviously smart investment. Dr. Hillman cautions that we will still need to brush and floss to prevent bad breath and gum disease, even if we use the new treatment.
Dr. Hillman's research, published in the February 2000 issue of the journal Infection and Immunity, has demonstrated the safety and effectiveness of the treatment in laboratory rats. Rats with the modified bacterium had fewer cavities after two months and showed no sign of adverse affects after six months. (If this seems like a suspiciously short observation time, remember that lab rats have a life span of at most three years, so the observation period is at least the equivalent of twenty years in a human subject.)
According to Dr. Hillman, the naturally occurring, decay-causing bacterium would eventually evolve into a strain similar or identical to his genetically engineered one. This could take another hundred thousand years or so; the new vaccine accomplishes the same thing right away.? A benign variant of a harmful organism could act as a vaccine, by preventing the bad germ from setting up housekeeping in a person; or could be used as an acute treatment, by competing with the closely related strain after an infection had started. The difference between this approach and the method of vaccination as it is now practised is that currrently, a killed or weakened species of harmful bacterium is introduced to prepare the immune system to fight a future infection by that bacterium. In the new method, a completely viable, live, but harmless variant is introduced which prevents or halts the infection by the harmful variant.
This development is of critical importance to public health. The overuse of antibiotics during the past half-century has resulted in many very dangerous germs acquiring a resistance to treatment. The race between pharmaceutical researchers and bacteria continues non-stop, but scientists are finding their choices increasingly limited. There is the definite possibility that strains of bacteria will develop that are resistant to any sort of antibiotic treatment. The use of genetically engineered harmless bacteria may turn out to be one answer to this problem.
A patent for the engineered bacterium has been issued to the University of Florida, which has licensed the technology to OraGen, a biotech company founded by, of all people, Dr. Jeffrey Hillman. (Watch for the IPO, then the buyout by the big pharmaceutical giant.)
One might think that dentists would be hostile to such a
new treatment. After all, if it succeeds, there will be a lot fewer
cavities to fill. However, the consensus so far seems to be that any procedure
that furthers the cause of healthy teeth will be welcomed by the profession. An
example of this kind of support is the endorsement by dentists of the
introduction of water fluoridation in the 1950's. Fluoridation reduced the
incidence of cavities, yet there are many more practising dentists now than
before the addition of fluoride.
? Stronger Variant
Q. By the way, the newspaper article refers to your method as "replacement
therapy". I had understood gene replacement therapy to refer to the
insertion of engineeered genes into the subject organism, or patient
(the critter with the disease). Did they get that wrong? I felt
uncertain about using the phrase in what I wrote so far, but all I had
for source was the clipping.
More about Monomers: single unit or molecule of a type that
can be connected in a chain to form compounds with properties different from the
single unit molecule. Monomer or "simple" sugars such as fructose and
sucrose are responsible for the "sweet" taste we associate with
"sugar" as a food additive. Glucose is the sugar stored in the liver
for food energy, and is the principal energy-providing nutrient of body cells.
Nerve cells and brain cells rely entirely on glucose for their food
source. When you put enough sugar molecules together, you get a Starch
molecule, which is what we are eating when we say we are eating
"carbohydrates". Actually, all sugars, simple and complex, are
carbohydrates. When you string sugar molecules into a long enough chain,
you get cellulose, which makes up the tough, stringy tissue of plants. Wood
fiber is mostly cellulose, that is, very long sugar molecules. Cows and termites
can digest cellulose. We can digest some of them, too, if we cook them to
break them down into starches and sugars. People get their best nutrition
from starches, found in wheat, rice, potatoes, and most other vegetable
products. Actually, meat contains a high percentage of carbohydrates as
well as protein.