After finishing the infectious disease course in basic sciences, I learned one overbearing truth – when in doubt, it’s probably Staph. However, in the case of dental caries (tooth cavities), another very popular group of bacteria is the culprit – Strep! More specifically, S mutans.
Dental caries are described as a “pandemic” by the World Health Organization, but in reality, they’re likely the most preventable diseases in the modern era. The basic pathway goes something like this: S. mutans lives in the mouth -> the bacteria ferment carbohydrates like glucose -> lactic acid is produced as a product of fermentation -> pH is lowered on the tooth’s surface.
The entire process of cavity formation is based on an equilibrium between mineralization and demineralization. In an acidic environment (pH < 5.5), demineralization is highly favored. Consequently, tooth decay ensues.
When the CDC outlined measures to add fluoride (which interrupts the process of decay) to the public water supply, the incidence of cavities plummeted. This nation-wide implementation is still heralded as one of the greatest decisions made on account of public health. However, just as with everything else, it’s all about moderation. Apparently, our guidelines for the amount of fluoride we’re adding to the water supply need to be revised.