With their often high-sugar diets and lax brushing habits, many children are particularly susceptible to cavities. An experimental new treatment could help, however, using enzymes to weaken the plaque that forms on the teeth.
As many readers will already know, cavities are caused by a bacterial biofilm – commonly known as plaque – that grows on the tooth surface.
According to scientists from the University of Pennsylvania, that biofilm actually consists of both Streptococcus mutans bacteria and Candida albicans fungus. The two are linked together via mannan molecules on the Candida cell walls, which bind to a glycosyltransferase (Gftb) enzyme secreted by the bacteria.
Making matters worse, the presence of sugars in the mouth causes Gftb to also produce gluelike polymers called glucans. As a result, the plaque can be quite difficult to remove, even with regular brushing.
Orally administered drugs are sometimes used to kill the S. mutans bacteria, although the researchers state that such medications don't necessarily affect the plaque that has already formed, plus they can harm both beneficial bacteria and oral tissue. Instead, a team led by Asst. Prof. Geelsu Hwang looked into ways of breaking the bond between the bacteria and the fungus.
In lab tests, the scientists applied three different mannan-degrading enzymes to biofilms growing on a tooth-like surface, within a saliva medium. After five minutes, it was noted that the thickness of the biofilm was significantly reduced – as was the bond between the bacteria and the fungus – making the substance much easier to remove via methods such as brushing.
And as an added bonus, the enzymes raised the pH of the saliva surrounding the biofilm, making the environment less acidic and thus less conducive to the formation of cavities. Additionally, because neither the bacteria nor the fungus themselves are attacked by the enzymes, they're not likely to develop a resistance to the treatment.
The team is now looking at reducing the application time down to as little as two minutes, with hopes that the enzymes could ultimately be incorporated into a non-alcohol-based mouthwash that children could use on a daily basis.
A paper on the research was recently published in the journal mBio.
Source: University of Pennsylvania
Yeah, that's not how evolution in organisms works.
Mutations and evolution in biofilm making will occur, and possibly accelerate in such microorganisms to increase chances of their survival.
What it is true is that to "reinvent" an effective way to create a biofilm using different sugars/bonding has a much lower probability then modifying a protein function by one or few point mutations as it occurs with antibiotic resistance.
Also worth noting is that it doesn't actually remove the plaque, just makes it more fragile so it can THEN be brushed away easier. The pH affect may help some.
Of course the naysayers will come along and say this breakthrough - if they can get it into a flavorful non-alcoholic mouthwash that only requires a daily 30 seconds of gargling or swishing will just promote oral colonization with a different yeast or bacterial.
Penicillin took decades to up-regulate the beta-lactam cell wall enzymes. And silver has been used to reduce biofilm integrity to directly kill bacteria - so why don't we see bacteria resistance to silver?