Coffee, tobacco, tea and soda are notorious for causing white teeth to yellow. When the enamel of your teeth wears and becomes thin, the yellow-ish underlying layer of your tooth shows through, causing your teeth to appear yellow rather than white. There are at-home ways to whiten teeth, including toothpastes and whitening strips, or your dentist can bleach your teeth for you. Below are some tips to help keep your teeth white and avoid having to have your teeth professionally whitened.
Brush your teeth regularly, at least twice a day. Using a hard bristled brush, or brushing too hard can damage your teeth and gums, so be gentle.
Floss your teeth after each brushing. Plaque, made of bacteria and debris from food, accumulates in the areas around the edges of your teeth, and flossing can help to prevent this, leaving your teeth less likely to become stained and yellowed.
Limit your intake of coffee -- and tea or other staining beverages. Instead of sipping on these drinks, enjoy them in a single sitting once or twice a day, and be sure to brush and floss when you're finished. Try using a straw when drinking staining beverages, to minimize contact with your teeth.
Try a tooth whitening product. Drug stores sell a variety of these types of products, including whitening strips, gels and toothpastes.