Fruits, such as apples, might be sweet, but they're also high in fiber and water. The action of eating an apple produces saliva in your mouth,which rinses away bacteria and food particles. The fibrous texture of the fruit also stimulates the gums and massages it. Eating an apple isn't the same as brushing your teeth with a toothpaste that contains fluoride, but it can protect you until you have a chance to brush. Pack either a whole apple or apple slices in your lunch to give your mouth a good scrubbing at the end of the meal.