According to Castle Dental, cider vinegar helps whiten teeth. It should be swished around the mouth full strength, if possible. However, this sometimes causes tooth sensitivity. Men's Health recommends making a mouth rinse with one part vinegar and two parts water.
Castle Dental identifies other ways to keep teeth white. Brushing the tongue helps remove bacteria that cause tooth stain. Crunchy vegetables, including raw carrots, apples and cauliflower, help remove stains and plaque that build up on teeth.
Men's Health states that acidic fruits, such as oranges, limes and lemons, wear away tooth enamel over time. The mouth should be rinsed with water after eating theses foods. In addition, baking soda should not be used to brighten teeth because it is too abrasive. Brushing with it regularly eventually erodes tooth enamel.