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)

How it works: Bleaching treatments at the dentist's office often involve directing a blue LED light at the peroxide gel on your teeth. The light and heat help to lock in the peroxide's whitening oxygens, making them react more quickly, explains Deutch. Professional grade at-home blue light devices have a similar effect. The faster process means less exposure to the gel, making these treatments better suited to sensitive teeth.

What to use: Deutch recommends the Glo Science Glo Brilliant Personal Teeth Whitening Device, $220, which comes with whitening gel that you apply directly onto teeth and a rechargeable light-up mouthpiece that goes over the gel. (A sensitive mouth solution is also included, which you can apply to your lips and gums beforehand). The light-up mouthpiece plugs into a charger that hangs around your neck, as it sits in your mouth for four consecutive eight-minute sessions. Yes, it looks a bit like a futuristic torture device, but used daily, the results are standout.

(If your teeth are ultra-sensitive, Gulizio recommends also prepping for your whitening treatment with an over-the counter teeth desensitizer, such as Dentist On Call SenzAway Tooth Desensitizer Gel, $4.29).

When you'll see results: 5-10 days (when used 32 minutes daily)

How it works: If you're opposed to chemical-infused bleaching treatments and toothpastes, but still want whiter teeth, you might opt for a DIY remedy. "Ingredients with highly acidic content can remove stubborn surface stains, possibly even faster than whitening toothpastes," says Stirneman.

What to use: To create your own at-home whitening solution, Stirneman recommends diluting some apple cider vinegar with water and mixing with an all-natural toothpaste (such as Tom's of Maine Simply White Toothpaste, $4.99). Mix three parts water and one part vinegar with your toothpaste, brush and rinse very well, so none of the acid remains on your teeth.

When you'll see results: Within 3 months

How it works: The key to keeping your teeth sparkling after using any of these treatments is to maintain your whitening routine. Try to cut back on food and drink that cause staining, especially within 24 hours after using a bleaching product, and swish with water after eating or drinking. Coffee addict? Try switching to iced coffee and drinking with a straw. If you're into tea, chug it. "Tea often stains more than coffee, because people tend to hold it in their mouths a lot longer when they drink it," says Deutch.

What to use: Deutch recommends maintaining your oral care by using a whitening fluoride rinse, such as Listerine Healthy White Restoring Anticavity Mouthrinse, $11.79, and cleaning hard-to-reach stains with Oral-B Glide 3D White Whitening Plus Scope Flavor Floss, $3.99.

When you'll see results: Continually