To prevent cavities and maintain good oral health, you need to regularly eat apples. Apple increases saliva flow in the mouth and prevents cavity buildup when it comes in contact with the teeth surface. Plus they are loaded with various vitamins and minerals that are required for your overall health. Try eating a full apple after your dinner to clear the interior part of teeth. Along with apples, you must also eat other crunchy fruits such as pears and guavas to increase salivary production which flushes away stains over time.