Regular, thorough brushing is a very important step in preventing tooth decay and gum disease. Brushing removes the bacteria that promote tooth decay and the plaque that can cause gum disease. Ideally, you should brush after every meal, because the bacterial attack on teeth begins minutes after eating. At the very least, brush once a day and always before you go to bed. Brushing your teeth isn’t complicated, but there is a right and a wrong way.