by Sarah Angle
Cavities are often associated with sugar or poor dental hygiene, but why does sugar actually harm our teeth? The answer is pretty wild.
Oral Microbiome:
Our mouths are home to a complex ecosystem consisting of many bacterial species that contribute to our oral health. These organisms occupy different niches (specific areas and roles) and reside on the teeth, gums, and tongue. Both beneficial and harmful bacteria are often present, so a balanced environment is necessary to prevent harmful bacteria from causing disease. Saliva (spit) plays a key role in maintaining that balance by acting as a natural buffering system that helps regulate the pH of the mouth.
Sugar Consumption:
The bacteria in our mouths can metabolize sugar. Bacteria that live on your teeth will form biofilms called plaque, which often exist in oxygen-poor environments. When sugars or carbohydrates are present, these bacteria ferment them and release acidic products. This acid production causes the pH in plaque to drop.
Because plaque forms a thick layer around the tooth surface, the acid is not immediately neutralized by saliva. As a result, enamel remains exposed to an acidic environment for an extended period of time. When the pH drops low enough, enamel begins to demineralize and weaken, which is how cavities form.
Figure 1. Depiction of cavity formation. Bacteria colonize teeth to form biofilms of plaque. The plaque can break down sugar to make acids (denoted here as H+). An increase in acid decreases the pH, weakening the tooth and resulting in cavity formation. Image made by the author using BioRender.com.
Acidic Sugary Beverages:
In addition to the high concentrations of sugar present in sodas, energy drinks, and sports drinks, these beverages are often acidic. Introducing sugar and acid to the teeth acts as a combined attack where the pH is lowered and bacteria are provided fuel to produce even more acid. This means that teeth start at a lower pH baseline and stay in the acidic environment longer.
Hopefully, this makes your dentist’s advice about soda a little more convincing!
For more: Check out this video and this podcast!
