Steve Thompson, Contributing writer

With all the emphasis placed on white teeth today, it can be disheartening to look at the mirror and see yellow or brown teeth staining, even if the color is just a few shades off.

But what causes stains on your teeth?

The most common scapegoat when it comes to teeth staining is coffee. According to the Atlanta Dental Group, "coffee smile" is caused by the deep brown color of coffee beans sinking into tooth enamel. Long-term coffee drinkers will start to notice teeth staining most prominently on the front of their upper teeth.

However, there are other things that can cause your pearly whites to look a bit dingy.

Tobacco According to eMedicine.com, using cigarettes, chewing tobacco or pipes can cause brown or black tooth discoloration, sometimes covering the entire bottom half of the tooth.

Foods and drink

WebMD reports that several different foods and beverages can cause teeth staining, from tea to cola, and even fruits and vegetables. Red wines might also be to blame, particularly for heavy drinkers.

Genetics

Just as some people are predisposed to high cholesterol or obesity, your genes can also impact teeth staining. If you are born with naturally thin enamel, for example, your teeth will stain more quickly than someone with stronger enamel.

Medicine

While medication is intended to make you well, it can also have a negative impact on other aspects of your health. WebMD reports that certain antibiotics, such as tetracycline, can cause teeth staining when given to young children whose teeth are still developing. There are also teeth staining problems related to anti-psychotic medications and antihistamines. If you know that you have to take these types of drugs on a regular basis, it is a good idea to inform your dentist and formulate a plan to avoid discoloration.

Physical damage

If you have suffered an injury to your mouth such as a broken jaw or cracked teeth, staining might occur. Fortunately, modern dentistry allows patients to take care of this type of problem with whitening agents and other therapies that can stave off discoloration.

Poor hygiene

Staining are also more common in those with poor dental hygiene. If you don't brush your teeth and visit the dentist regularly, plaque build-up will cause discoloration. The same goes for people who brush too aggressively. The best defense is to discuss the appropriate care with your dentist.