You brush your teeth twice a day for two minutes at a time. Your floss to get bits of food out from between your teeth. You avoid sugary snacks like the plague. Yet somehow, you’re still getting cavities. Meanwhile, your friend who hardly ever flosses ends every dental checkup with a clean bill of health. What gives? According to your dentist, some people are simply more vulnerable to getting cavities than others. Let’s examine five reasons why.