By now, just about everyone knows the alleged importance of brushing twice everyday. It’s become a common lecture for parents to grab hold of, a routine for many, and a completely misunderstood principle for just about all. While most of us know to brush twice daily (and even do it with varying results), almost no brushers know why dentists suggest you build this into your habits. Beyond simply brushing twice, once in the morning and again at night, it is important to know why dentists recommend this so that you can ensure you’re actually doing it correctly.

This principle is best understood once we accept that saliva does a whole lot more than simply keep your tongue wet and slide food down your throat, it also has tremendous bacteria-fighting properties and even serves as a sort of toothpaste and dental floss. How does this connect to brushing twice daily? Simply put, saliva production is all but nonexistent during sleeping hours. This means that your teeth, which are usually somewhat protected by saliva, are left almost entirely vulnerable to bacteria while you sleep. Obviously, this is the reason why you should brush just before bed, as the fluoride serves to protect your teeth while you sleep. But why first thing in the morning? Well, when you first wake up, it takes time for saliva to get up and running; if you eat and drink before brushing first thing in the morning, you are putting your teeth and gums at risk by throwing off the acidity balance in your mouth. Basically, it is crucial that your teeth are protected throughout your sleep by a late-night brushing and then again fortified by a pre-breakfast brush, which sets your saliva up for success throughout the day.