Though it may sound obvious, the best way to keep cavities at bay is to keep your teeth clean. Brush your teeth at least twice a day, ideally after every meal—and be thorough! Dr. Harry Höediono, president of the Ontario Dental Association, says that while most people spend about a minute brushing their teeth, the ideal should be three times that. Brushing before bed is particularly important, since letting bacteria linger on your teeth overnight can allow enamel-damaging acid to form (ultimately leading to cavities). When you do brush, work carefully, from the gums to the tips of the teeth. “Don’t scrub!” says Dr. Höediono. “It’s best to use nice, gentle strokes. Scrubbing only gets at the food particles that are on the flat surfaces of your teeth. If you want good results, start at the gums.” Also be sure that you’re using fluorinated toothpaste, because fluoride helps makes your tooth enamel more resistant to decay.