Teeth whitening involves bleaching your teeth to make them lighter. It can't make your teeth brilliant white, but it can lighten the existing colour by several shades. Who can do teeth whitening? To help you narrow down the list of whitening kits that will meet your needs, we tested the best options on the market. We tried out dozens of whitening kits, following each brand's specific instructions. Throughout the test, we paid close attention to how easy it was to use the product, whether we experienced any discomfort or teeth sensitivity, and how effective the product was in whitening our teeth. We then took careful notes on the appearance of our teeth before, during, and after the whitening process.An orthodontist from our Medical Expert Board reviewed the contents of this article for medical accuracy surrounding dental hygiene and the efficacy of active whitening ingredients. Still, if you know your teeth are particularly sensitive, you can aim for a whitening product with 3 to 10 percent carbamide peroxide, says Dr. Izhaky.

If used correctly, at-home kits will certainly lighten your teeth by a few shades. You might want to pop to the dentist for at least a thorough dental clean before starting your treatment, as plaque and tartar on the teeth can stop the bleaching agents penetrating stains, so getting everything scrubbed clean first is bound to boost results. What else will help my teeth stay white?A person can also get whitening products or services through their dentist. Dentist-supplied whitening products are usually more concentrated. The options available directly from dentists include: Pens. Whitening pens allow for easier and more precise whitening on-the-spot, which Dr. Kalasho says are helpful for minor staining—but most of it washes away with your saliva, so more intense stains probably won’t show ultra noticeable results. To be sure tooth-whitening is worth your time and money, talk to your dentist before you use an over-the-counter tooth whitening kit. Is Teeth Whitening Safe? Finally, we were surprised how much brighter our teeth became in testing this product—we felt the kit more than earns its place on our list and is well worth its cost. We even think it may have been more effective than previous whitening treatments we've done in the past at the dentist's office. Per Dr. Kalasho, common whitening ingredients that work well for at-home use are carbamide peroxide and hydrogen peroxide. For carbamide peroxide, look for a percent of around 35 percent; for hydrogen peroxide, you’ll want something with a 10 to 15 percent concentration.

Phthalimidoperoxycaproic Acid (PAP): This active whitening ingredient is scientifically proven to safely remove stains and discoloration from the tooth surface without causing sensitivity or enamel damage. Whitening strips can be a messy, awkward affair, but the Crest 3D Whitestrips for Sensitive Teeth could not have been easier for us to use. The strips went on and came off without any trouble and didn’t cause any pain, stinging, or sensitivity during or after use. And they worked, too—we were able to see a noticeable difference as soon as we took the first strip off our teeth and felt confident that the results would keep improving from there (with this particular kit, you’re directed to use the strips for 28 days). Any dentist can whiten teeth as long as they're registered with the General Dental Council. Registered dental therapists and dental hygienists can also carry out teeth whitening on the prescription of a dentist.Generally, though, Dr. Izhaky says strips are safe to use twice a day for up to two weeks for a maximum of 30 minutes at a time. Depending on the ingredient percentage, she adds, gels can be used for one to two hours per day for two weeks as well. The Journal of Clinical Dentistry: “Crossover clinical investigation of a whitening chewing gum for inhibiting dental stain formation in conjunction with tooth brushing.” There are many teeth whitening methods, including treatments at your dentist's office and kits you can buy over the counter. (Photo Credit: E+ / Getty Images)

No matter what treatment you use, there's a chance your gums will be sensitive to the chemicals used in teeth whitening, particularly if you already have sensitive teeth. There's also a chance of burns to gums and some of the whitening kits used at home can harm tooth enamel. What if I'm not happy with the results? Scandinavian Journal of Dental Research: "Iron Staining Of The Acquired Enamel Pellicle After Exposure To Tannic Acid Or Chlorhexidine: Preliminary Report." Teeth whitening is a form of dentistry and should only be carried out by a dentist or another regulated dental professional, such as a dental hygienist or dental therapist, on the prescription of a dentist.READ NEXT: The best toothpaste to buy Will I get the same results at home as I would at the dentist? Sodium Hydroxide: A commonly used ingredient in teeth whitening that safely and gently removes stains from within the enamel layer. More and more people are paying for brighter, whiter teeth. But does teeth whitening work and is it safe? Here are the answers to common questions about the treatment. What is teeth whitening? Leading New York City cosmetic dentist, Dr. Stephanie Dumanian, highly recommends this kit by GLO. “GLO products are top of the line. Their take-home whitening kit provides fast whitening results without being abrasive to your teeth or gum. The advanced technology GLO’s kit offers can help to amplify whitening results received in-office and help maintain those results over time.” Mind you, Dr. Dumanian is the reason behind the popular glimmering smiles of celebs like Busy Philipps and Ashley Park, so you know she'll only suggest the best of the best. For safety reasons, in the UK, at-home teeth whitening kits may contain hydrogen peroxide at concentrations at up to 0.1%, whereas your dentist, using a custom-fitted mould, is able to safely use a concentration of up to 6% without harming teeth or gums. This means the professional treatment is usually able to achieve more noticeable lightening results. Dentist-only treatments such as laser whitening (in which the bleach solution is activated by a laser shone onto teeth) are also much faster, taking only 1-2 hours.

Sensitive Teeth Whitening: If you have teeth sensitive to whitening, achieving a brighter smile without side effects is probably your most important consideration. Fortunately, there are many products that provide exceptional teeth whitening results without causing pain for those with teeth sensitive to whitening. Crest 3D White Whitestrips Sensitive + LED Light provide subtle whitening by using the same ingredients dentists use in a less concentrated formula. This product is ideal for people with teeth sensitive to whitening and it only takes 30 minutes, once a day to achieve a brighter smile. I used to buy Crest 3D for my son but decided to try this one because Crest is getting more and more expensive. I was a little skeptical in the beginning but it actually worked, delivering the same result as the Crest 3D with 1/3 of the price and 1/2 treatment term! We are very satisfied with product and will continue to use it.” — Anne Initially, we couldn’t leave the tray in for the recommended 15 minutes because it was so uncomfortable. But over time, we did get used to it. The best part was that our teeth whitened. Even though we only left it in for about eight minutes, our teeth went up a full shade. It hurt, but the pain was worth it in our eyes. We also started with the highest concentration possible, which we wouldn’t recommend if you have sensitive teeth or have never whitened your teeth before (in that case, you may want to start with the lowest concentration and work your way up from there). You have tooth discoloration when your teeth are stained or darkened. It might affect the whole tooth or look like lines or spots on the tooth's surface. There are two basic types of tooth discoloration: Intrinsic, or internal, discoloration happens inside the tooth. Things that can cause this type of discoloration include aging, tooth injuries, some health conditions, and certain medications.Number of Daily Applications: Be sure to take note of how many times a day you should wear the strips. This will vary by product and should be clearly stated in the teeth whitening instructions—some require one application, while others are meant to be worn twice a day. International Endodontic Journal : “Present status and future directions – Managing discolored teeth.” Whether you use an at-home tooth-whitening system or have your teeth bleached by a dentist, you can help maintain the results by regularly brushing and flossing and keeping up with dental appointments.