The causes of tooth discoloration can actually vary, ranging from easy-to-change lifestyle choices to dangerous internal illnesses or other medical conditions. While the latter is certainly scary, the vast majority of yellow teeth are caused by simple activities that are easily changeable. And while modifying your behaviors or environment might not bring back the brilliant white color, it will stop or limit your teeth's continued discoloration.

Let's start with the most common and work our way down:

Smoking: The Biggest Cause Of Tooth Discoloration

It's true. The biggest single contributor of yellow teeth is smoking tobacco products. I won't go into the entire chemical process, but let's just say that the chemicals within cigarettes, cigars and even more illicit substances wreck havoc on your chompers. The result is tooth discoloration.

That's the bad news. The good news is that you can easily cut this variable out of your life by quitting. Sure it's tough, but there are more support groups and cessation programs now than every before. Check out your local health department for cheap or even free programs.

Coffee: It Will Turn Your Teeth Yellow

I'll admit that it's hard to face our fast-paced world without a cup of joe in the morning, but the truth is that it could be killing your smile. Pretty much any dark drink can cause tooth discoloration, but coffee is especially nasty.

Like smoking, this is easy to remedy: Quit drinking it! I know it's easier said than done, but think of some other ways to get your energy fix that won't discolor your teeth.

Your Tap Water Could Be A Cause Of Tooth Discoloration

It's hard to imagine, but the water coming out of your sink could actually be ruining those pearly whites of yours. There are several naturally occurring minerals in ground water supplies that react negatively when they hit your teeth, resulting in discoloration. Sadly, it's so expensive to filter these particles out that most municipal water systems let them straight through (after all, they won't make you sick). It's also common amongst those who use private well water.

Try a really good water filter. You can try some of the inexpensive ones that fit on top of a water pitcher and are super easy to use, like this Brita Water Filter (it costs about $15). Or, if you've got the finances or ability, consider adding a large-scale, in-line water filtration system to your water supply (be ready to spend thousands, but it's worth it).

Oral hygiene: Brush, Floss and Use Mouthwash

As if you need another reason to take care of your teeth, not doing so could be causing that nasty yellow color. Proper oral hygiene is important for a variety of reasons (studies have suggested that dirty mouths can actually cause a huge assortment of health problems), but most of us are pretty good about taking care of our teeth and gums, but more often than not, we're not doing as good of a job as we should.

I'd highly suggest you check out the recommendations of the American Dental Association for tips on proper brushing, flossing and approved mouth washes.

Drugs: An Unnecessary Cause Of Tooth Discoloration

Have you noticed a correlation between those who use illegal drugs and the condition of their teeth and gums? It's not a coincidence; using illegal drugs will literally destroy your teeth, least of which they'll turn them yellow.

I'm not going to beat you over the head with reasons why you should stop taking drugs, should this apply to you, that's not my place. But what I will tell you is that illegal drugs is one of the biggest causes of tooth discoloration. Meth is probably the biggest contributor, as the chemicals within it wear away tooth enamel very quickly.

A common urban myth is: "Drugs don't ruin your teeth, it's just that many people who take them stop brushing their teeth or paying attention to their mouths." While it's true that many users stop using proper oral hygiene, the harsh reality is that drugs themselves will cause tooth discoloration, it's all about the chemicals.

Oh, and I should point out that marijuana is included in that list. It's similar to smoking tobacco in that it will cause tooth discoloration, especially in instances of continual use.

Your Teeth Look Like What You Eat

Isn't it funny how unhealthy food seems to cause all sorts of problems? Well, as you probably guessed, your diet plays a huge role in how your teeth look.

Highly processed foods and foods that are high in sugar are especially dangerous to our mouths. And no, despite more urban legends, fruits won't destroy your teeth just because they are high in sugar. Sure, they have more than most other natural foods, but they pale in comparison to some of the artificial stuff that most people consume every day, such as soda pop, candy and even unhealthy snacks. Make sure you brush, but by and large, fruit is not one of the causes of tooth discoloration.

The best way to avoid this is to eat healthy. As an added bonus, you're whole body will reap the rewards. There really is no down side to a healthy diet.

See Your Dentist

A dental cleaning is one of your best weapons against discolored teeth. Most experts recommend seeing your dentist about once every six months for check ups and cleanings. Don't skip these, they are very important, and most health insurance policies actually encourage you to keep up on your dental cleanings (it often staves off more expensive dental problems later).

While you're at it, you can ask your dentist if he can help identify the causes of tooth discoloration in your instance. Nothing beats a professional opinion!

What To Do About Tooth Discoloration?

Okay, we've discussed the biggest contributing factors of yellow teeth, but that probably doesn't help those who are looking for ways to actually reduce that yellowed look. If you're looking to whiten your smile, I'd highly suggest you check out this article: Safe Teeth Whitening. It's full of great ideas on making your teeth white, and debunks several of the old wives tales and even calls out a couple of unsafe but common practices.

Using safe teeth whitening products, in conjunction with knowing and understanding what causes tooth discoloration is your one-two punch in creating a healthy, happy mouth.