Hundreds of billions of bacteria live in your mouth. Although many are good, some can form plaque, cause cavities, and create gingivitis. This can lead to gum disease. To avoid this causing more severe illnesses and systemic diseases, you should practice good oral hygiene daily. This includes brushing twice a day, flossing, avoiding tobacco, limiting soda and alcohol, rinsing with mouthwash, and ensuring you get an adequate supply of calcium and other vitamins.