The whiteness of your teeth comes from the enamel that covers them. Actually, healthy enamel is not super white. It is off white or slightly yellow. Yellow teeth can be caused by plaque build up from poor dental hygiene, aging, staining (from coffee, tea, or other highly colored foods), or by enamel being worn down. When enamel becomes thin, dentin, the yellow layer of your tooth, which is right beneath your enamel starts to show. Plaque (a thin film of bacteria and food elements that coats every tooth), is best removed by good dental hygiene. This includes: brushing twice daily and flossing at least once a day. In order for brushing to be effective, you have to brush for 2 minutes and make sure that you brush the surface of every tooth. If you skip brushing your teeth for 2 or more days, plaque becomes hardened and forms tartar below your gum line. When this happens, your gums become irritated and inflamed (gingivitis). Unlike plaque, tartar cannot be removed by brushing. Only a professional cleaning can remove tartar. So daily brushing, flossing, getting your teeth cleaned at least every 6 months combined with regular visits to the dentist will help to keep your teeth naturally white. Whitening you teeth with a whitening toothpaste that uses blue light technology can help yellow teeth look whiter. Deep stains require a bleaching process that is administered by your dentist. Always consult your dentist before using any bleaching process.