2. Bad bacteria thrive when the pH balance in your mouth drops
As you may remember from chemistry class, the lower the pH, the more acidic something is. The higher it is, the more alkaline (or basic).
Just like in the rest of your body, maintaining a healthy pH balance in your mouth is vitally important. That’s because your pH levels can either encourage probiotics (which we just learned are good bacteria) or fuel the growth of bad bacteria. It all comes down to the foods you eat and how often you eat them.
For example, when you eat a lot of sugary/starchy or highly acidic foods (candy, soda, bread, crackers, lemons, oranges, etc.) the pH in your mouth drops to 5.5 or below. This creates an acidic environment that fuels bacteria in the mouth to produce lactic acid, which in turn causes tooth decay.
Your saliva can help neutralize this acid by remineralizing teeth, buffering acid, and clearing away food. But depending on how much acidity is in your mouth, it may take a while for this to happen — sometimes up to several hours. This is plenty of time for bacteria to wreak havoc on your teeth and gums.
On the other hand, maintaining an overall healthy and balanced diet (and maintaining a neutral pH level of 7.0), will allow you to handle the occasional sugary or acidic meal without experiencing a shift to cavity-causing bacteria.