A dentist-approved guide to teeth whiteners

At-home teeth whitening kits can definitely be effective, depending on the severity of tooth stains and oral sensitivity. Teeth stains occur on both the surface and inside of the tooth, and can be caused by many things, including:

• Certain foods and drinks, including coffee, red wine, dark soda and specific fruits like blueberries
• Tobacco use
• Poor oral hygiene, including inadequate brushing and flossing

Teeth whitening products can remove some — but definitely not all — stains, said Matt Messina, DDS, a dentist based in Ohio and a spokesperson for the American Dentistry Association. Cavities or tooth decay may make teeth turn a dark gray color which won’t go away with at-home whitening, he noted. The same goes for other oral problems like plaque build-up or gum irritation.

“You need healthy teeth and gums before you even think about whitening,” said Messina. “It’s not all about color — that’s just one part of the overall picture.”

If you’re unsure about discoloration of your teeth, check with your dentist first to figure out the underlying problem and make sure you’re a candidate for teeth whitening. Some issues, like plaque, can be removed via regular professional cleanings at a dentist’s office. Others can be solved by whitening.

Most teeth whiteners have an active ingredient, typically hydrogen peroxide or carbamide peroxide, which penetrates the enamel of your teeth and breaks down the discoloration without softening or thinning your teeth, explained Ben Elchami, a dentist and co-founder of DntlBar, a walk-in dental office based in New York. The difference between teeth whiteners is the concentration of those active ingredients.

The higher the concentration and longer the active ingredient is held against your teeth, the more effective the whitener typically is. In a dentist’s office, a professionally trained dentist is able to use a high concentration of whitener while protecting your gums, making it the most effective (and often most expensive) way to achieve a whiter smile. If you’d rather whiten at home, Messina shared some of the common types of at-home whiteners.

• Whitening toothpastes work best for surface stains and maintenance after you’ve used another form of whitening. Its effectiveness is lower than other types of whiteners, but it’s helpful when combined with other kits, said Messina.
• Whitening strips have a thin layer of hydrogen peroxide and are placed over the teeth for a set amount of time, then removed. They are typically more affordable but less effective than whitening gel, and are used in tray kits and dentists’ offices.
• Some kits come with custom trays that hold whitening gel. Users fill the tray with the gel and wear it for a couple hours. Whitening gels are stronger and more effective at whitening teeth than strips and achieve optimal results in around 10 to 20 days. Some dental offices will make custom trays that help users to achieve better results.
• Some gel whiteners also use LED lights to help activate the whitening agent in the tray, explained Elchami.

Teeth whitening is typically safe. But some at-home products can cause gum pain and tooth sensitivity, which makes going to the dentist beforehand all the more important. Elchami explained that some users may not be able to handle higher concentrations of whitening agent and that a dental professional can help them find a product that works for them.

In addition, beware of beauty “fads” or do-it-yourself approaches to teeth whitening, which can have negative side effects like reducing teeth hardness or increasing their sensitivity. A common example is using charcoal toothpastes — the abrasiveness of the ingredients can actually remove the enamel from your teeth — “like sanding a floor,” said Messina. A 2017 study by the American Dental Association found no sufficient evidence that charcoal can improve tooth color or boost health — in fact, the study found increased cavities and enamel erosion in some cases.

The most powerful whitener may not be the best option for you, said Messina. When shopping, look for products with the American Dental Association’s stamp of approval, which indicates the product has been independently tested in the ADA’s own clinics and laboratories for safety and efficiency and is approved by dental professionals. A product must adhere to the initial standards set by the ADA to earn the stamp, and needs to re-apply for approval every five years.

Most kits are used every seven to 10 days and then monthly or even annually for maintenance. Make sure to follow the instructions. Messina said it’s not smart to ignore directions with the hopes of getting faster (or more dramatic) results.

“If it says 30 minutes, an hour isn’t better,” he said. “It may instead dramatically increase your tooth sensitivity, making it hard to handle cold things like ice cream or even water.”

Start simple. Messina recommended trying a whitening toothpaste or strips first and working your way up in concentration. If at any point you notice sensitivity or irritable gums, stop what you’re doing immediately and contact your dentist.

“Be honest with us,” he said. “We’ve all been there. Your dentist is there to help you.”

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