Your back teeth (called premolars and molars) are the most susceptible to getting cavities. This is because they have grooves and depressions otherwise known as pits and fissures in them, which help you grind down your food during eating. The problem is that they can also be the perfect place for bacteria to accumulate and cause damage. Daily brushing and rinsing after meals can prevent food and sugar from staying in those fissures too long.