Why do we brush our teeth? Simple answer: to prevent cavities. We need to remove plaque, the transparent layer of bacteria that coats the teeth. ... Brushing also stimulates the gums, which helps to keep them healthy and prevent gum disease. Why it is important to brush your teeth? Brushing Your Teeth It is important to brush your teeth to prevent gum disease. Refusal to brush one's teeth for several days can lead to the onset of gum disease. Brushing ensures the removal of plaque, which is the primary cause for tooth decay and gum disease; it also arrests the build-up of any plaque formation.