Yellow teeth? Not so much fun to look at -- especially when you're staring into a mirror. A trip to the dentist is also low on most people's list of enjoyable activities. But achieving a movie star white smile is near the top. After all, research indicates that 96 percent of adults believe white teeth are vital to a person's appearance. Luckily, you don't need a session in your dentist's chair to learn how to whiten teeth. Pro-level teeth whitening is something you can take care of at home.

Most yellowing and stains come from years of drinking coffee, tea, red wine, cold-pressed juice and other fun (though highly discoloring) food items. "When patients come in for teeth bleaching, a lot of the time I recommend at-home teeth-whitening treatments first," says New York City dentist Dr. Andrew Deutch, DDS. "It is only the deepest, most stubborn stains [those that have penetrated the inner structure of the tooth] that require in-office treatments."

Here's how they work: Dentists use carbamide peroxide, hydrogen peroxide or laser whitening to penetrate tooth enamel and break up the molecules that stain teeth. (Note: These ingredients do not wear away at enamel -- they simply release discolored molecules from pores in the enamel). The best at-home teeth whitening treatments use lower concentrations of hydrogen peroxide to achieve the same effect -- for a fraction of the price. The main difference is that pro treatments are stronger, and thus work faster. "That means you'll see results more quickly and you ... can avoid the irritation issues that [sometimes] come with over-the-counter products," explains Dr. Michael Gulizio, DDS, of Core Smiles in New York City.

At-home teeth whitening is a billion-dollar industry, so it's easy to get lost. But the following DIY teeth whitening treatments are effective and dentist-approved. Keep the coffee to a minimum, and these will work as well the pros.

How it works: The first step to a consistently whiter smile is nixing the stains that accumulate on the surface of your teeth (aka, extrinsic stains). That means incorporating whitening treatments into your everyday routine by investing in an electric toothbrush, as well as some pro-approved whitening toothpaste.

"Because of their oscillations, electric toothbrushes remove stains better than if you were to do it by hand," says Deutch. "Whitening toothpastes are quite abrasive, so they're great for taking off surface stains." (It's also important to thoroughly clean your teeth this way before using any other bleaching product).

What to use: Deutch recommends the Oral-B ProfessionalCare SmartSeries 4000 Electric Toothbrush, $124.99, or Sonicare HealthyWhite Rechargable Sonic Toothbrush, $119.99. Go Smile's Sonic Blue Teeth Whitening System, $129, is also a great option, as it comes with a hydrogen peroxide gel, which you layer with your toothpaste for extra whitening power.

For dentist-approved whitening toothpaste, try Crest 3D White Radiant Mint Whitening Toothpaste, $5.99 (Deutch's personal go-to), or Colgate Optic White Express White Toothpaste, $3.99. Chicago dentist Dr. Timothy Stirneman, DDS, also swears by Opalescence Whitening Toothpaste, $9.99.

When you'll see results: 1-6 months

How it works: Over-the-counter whitening strips use low levels of hydrogen peroxide to bleach your front teeth over a matter of weeks. The products are affordable, effective and widely available.

The only downside to whitening strips is that they can take many uses to work. "Saliva de-activates the active whitening ingredient," Deutch says. Since whitestrips sit exposed in your mouth, they don't stay effective for very long. "Depending on how often you use them, you might have to wait a month to get the results you want," he says. Luckily, dentists agree that with consistency, the products offer impressive results.

What to use: Deutch and Stirneman sing the praises of Crest 3D White Whitestrips, $27.99. "They have many different varieties for patients' needs," says Deutch. For example, the Gentle Routine kit suits sensitive teeth and gums, while the One-Hour Express kit offers faster results at a slightly higher price.

When you'll see results: 12 days to 1 month (when used daily for 30 minutes)

How it works: While whitening strips don't provide any kind of barrier between your saliva and the active ingredient, over-the-counter whitening trays do. "For that reason, you might see results quicker," says Deutch. "As long as you stick with it."

With over-the-counter whitening kits like this, you receive a pre-made tray, which you fill with hydrogen peroxide gel and fit around your top teeth like a mouth guard. The tray surrounds your teeth, unlike strips, which simply sit on top. The tray is not custom, so it might not fit perfectly in your mouth or feel as comfortable as the strips, but you will likely see more immediate results.

What to use: We recommend the Plus White 5 Minute Speed Whitening System, $10.90, available at drugstores. Squeeze the included whitening gel into the tray, place it in your mouth and wait for five to 20 minutes.

When you'll see results: 1-2 weeks (when used twice daily)

How it works: Pro whitening trays that you'd get from a dentist offer a custom fit, based on a mold taken in-office, as well as higher concentration whitening gel. The trays are clear and fit perfectly to your teeth, so they tend to be more comfortable than the clunky over-the-counter option (meaning you might be more motivated to stick with them). However, if you're severely dentist-phobic, but still want pro-grade results, there's a way to create a custom set of clear trays at home.

What to use: Smile Brilliant's Teeth Whitening Trays, $119.95, work just like those you'd receive from a dentist. In the mail, they send you the materials to create a custom mold of your teeth -- send it back, and within a week you'll receive your trays, along with syringes filled with a 22 percent carbamide peroxide gel, which is significantly more concentrated and effective than most at-home products. (You can choose to receive 3, 6 or 9 syringes, each of which lasts for 3-4 full applications). Wear the trays on top and bottom teeth for a couple hours per day, and you'll find dramatic results within a week or two. It's the closest you'll get to an in-office treatment without having to spend 600 bucks and an afternoon at the dentist's.

When you'll see results: 4-14 days (when used for 1-3 hours, daily)