In the era of selfies and social media, we all want to look our best. Often, that starts with teeth whitening.
Teeth whitening is cheaper and more accessible every year. The more popular it gets, the more money there is to be made. Sadly, this has resulted in many harmful whitening methods, products, and scams that fool or hurt consumers.
Teeth whitening is a 15-billion-dollar industry, but the marketing behind these products usually fails to tell you what you’re really getting.
So, if you’re considering whitening your teeth, this guide is for you.
I want to make sure you understand the ins and outs of this process before jumping in. After all, you only get one set of teeth in life, and it’s all too easy to damage them permanently.
By the end of this post, you’ll know:
- How whitening actually works
- What’s safe and what’s not when it comes to teeth whitening
- How to spot a whitening scam
- How to whiten teeth most effectively
- The safest way to whiten your teeth
Disclosure:Ask the Dentist is supported by readers. If you use one of the links below and buy something, Ask the Dentist makes a little bit of money at no additional cost to you. I rigorously research, test, and use thousands of products every year, but recommend only a small fraction of these. I only promote products that I truly feel will be valuable to you in improving your oral health.
Why Teeth Turn Yellow
Before we talk about how to whiten teeth, I want to share the common factors that cause teeth to turn yellow.
Teeth yellowing is a normal part of aging.
As our hair turns gray, our teeth turn yellow simultaneously. And it’s the inner part of the tooth called dentin—not the outer enamel—that yellows.
Over time, your new dentin appears darker, while the enamel is thinner due to wear, grinding, or exposure to acidic foods and drinks. The discolored dentin then reflects through the enamel like a prism, making the tooth look yellow.
Besides aging, your teeth may turn yellow or grayish due to:
- Taking tetracycline, a powerful antibiotic, before age 10
- Falling on or hitting a tooth
- Being exposed to too much fluoride (also called fluorosis)
- A rare dental disorder called amelogenesis imperfecta (AI) which makes the teeth yellow or brown
- Genetics, which determine the color of your teeth from birth
- Silver (amalgam/mercury) fillings
Tooth enamel can also become stained when you drink tea, coffee, or wine, or when you smoke tobacco. This does not affect the inner color of the teeth, and can be remedied with a good stain-removing toothbrush and toothpaste.
How Teeth Whitening Works
Teeth whitening works by actually changing the color of the inside of the teeth (known as intrinsic whitening), or removing stains from the outside of the teeth (known as extrinsic whitening).
“Intrinsic whitening” refers to whitening the dentin, or inner part of the tooth, which soaks up hydrogen peroxide gel (also called whitening gel or bleach) and becomes lighter.
There are other ways to intrinsically whiten, and these involve protecting your teeth from premature or accelerated aging. Simple lifestyle changes like staying better hydrated can prevent acid wear (plus, hydration reduces your risk of cavities!).
When the inner part of the tooth is whitened, the color that’s reflected through the outer enamel of your teeth is lighter, making the tooth look whiter and brighter, overall.
Contrary to what you may have thought, bleach lightens the inner tissue of the tooth, not the hard, outer enamel.
Removing staining on enamel (the outer part of the tooth) is called “extrinsic whitening.”
The stains left behind by smoking or drinking wine, tea, or coffee are usually easily removed with a polish by your hygienist at a teeth cleaning or with polishing and whitening toothpaste.
Unfortunately, many extrinsic whitening techniques to remove stains aren’t all that safe. Some of them, like Crest Whitestrips, don’t work consistently and expose your sensitive gums to dangerous chemicals.
I’ll cover the best teeth whitening methods below… But what’s the best way to whiten teeth for you?
What is the best whitener for your teeth?
If you have extrinsic discoloration/staining, start by trying a stain-removing toothpaste for a couple of weeks. Going for a stain-removing electric toothbrushing can make a big difference here, too. Staining can also be removed during a professional teeth cleaning.
If you have intrinsic yellowing, no amount of stain-removing toothpaste can lighten the inner color of the tooth. You’ll need to whiten your teeth using a bleaching gel that is held up against the teeth (but don’t run out to buy whitening strips quite yet!).
What to Know Before You Try Teeth Whitening
Start with healthy teeth.
You can’t remodel the kitchen with dry rot in the floorboards.
Whitening your teeth when you have gum disease, exposed roots, cavities, crooked teeth, gum recession, or other untreated issues can cause further pain and problems. Plus, you’ll have wasted your time and money, since the whitening likely won’t take on damaged teeth.
An ethical dentist will tell you this and not take your money before fixing any dental problems first.
Be prepared for tooth sensitivity.
One common side effect of teeth whitening is sensitivity in the 24 hours after your teeth have been exposed to whitening gel. You can take a pain reliever like ibuprofen if the sensitivity is too much to bear.
Whitening isn’t a one-time thing and won’t last forever.
Teeth are always yellowing as part of the aging process.
They’re also always becoming stained by the foods and drinks we consume. No matter where or how you whiten your teeth, it won’t last forever.
Most teeth whitening results last from 6 months up to 2 years. The length of time depends on how easily your teeth stain, as well as your diet and lifestyle.
There’s also a rebound effect from teeth whitening, where teeth will relapse slightly in shade. You may be whitening your teeth and stop at a certain point once you’re happy with the results, but I would recommend going a bit beyond that because of the rebound effect.
One size does not fit all.
Custom trays help ensure that bleach stays where it’s intended—not on your gums, where bleaching gel causes free radical reactions and damages them.
Since everyone’s smile is different, we shouldn’t all be using the same size tray to whiten our teeth. This is why I recommend the custom whitening trays and strips available from your dentist.
Whitening gel must be kept away from soft tissue.
A common side effect of teeth whitening is soft tissue irritation. This usually happens when the whitening solution gets on the gums.
You might ingest a bit of the gel in take-home whitening kits, which can cause nausea or vomiting. Be cautious to spit out any gel on your teeth.
The results you get from teeth whitening depend on what your teeth were like when you started.
Some people think whitening erases all the damage they’ve done to their teeth over their lifetimes, but the opposite is true: The better you’ve cared for your teeth, the greater the results.
The more you’ve maintained regular dental appointments, brushed and flossed regularly, and avoided damage and discoloration, the whiter your teeth will appear after a teeth whitening service.
You can overdo it.
Over-whitening—from using too much whitening gel or reapplying too often—can permanently damage teeth. Over-whitening can also make teeth look translucent or discolored, which can’t be fixed without replacing the tooth completely.
Don’t worry about having the shiniest smile you can get. Not only can this actually age your teeth faster (and make yellowing worse), white teeth aren’t actually indicative of a healthy smile.
Teeth whitening can be safe—when done as recommended.
For the most part, teeth whitening is safe—as long as it’s done correctly. What most people don’t realize before having their teeth whitened is this: because you’re dealing with live tissue (unlike hair or nails), teeth whitening can cause damage, pain, and sensitivity.
I’ll cover these in detail below, but there are several methods of teeth whitening I do not recommend because of safety concerns.
Which Teeth Whitening Method Is Right For You?
There are many different ways to whiten teeth, whether at the mall, at the dentist, or in the comfort of your own home. Here’s a breakdown of the options for a professional effect.
The name “whitening toothpaste” is a bit misleading. Toothpaste can only lighten your teeth superficially—and this is only accomplished by being more abrasive than regular toothpaste. In reality, all toothpastes actually remove some surface stains because of their abrasiveness.
Whitening toothpaste can remove staining on your teeth, but it cannot change the internal color of your teeth.
The best teeth whitening kit is actually an excellent stain-removing toothbrush like the Goby brush, along with a stain-removing toothpaste.
Pros: Whitening toothpaste is great for removing staining, but don’t use it for more than a few weeks a time in order to protect your teeth and gums.
Risks: Whitening toothpaste can cause sensitivity, be too abrasive on the teeth, and lead to gum recession. Use it sparingly (as mentioned above), and brush gently, with proper technique, while regularly checking in with your dentist to make sure you’re not committing any lasting damage.
Professional Teeth Whitening at the Dentist
If you choose to have your teeth whitened by your dentist, you’ll come into the office for a few hour-long sessions.
During each session, a high concentration of peroxide will be applied to the teeth before a light is used to (supposedly) accelerate the chemical reaction and the whitening process.
Pros: If you need your teeth to be whitened in just one day, this is a good option because it’s fast. Theoretically, since the dentist is present, you reduce the risk of damage to your teeth and gums.
Risks: I’m not a fan of these light systems and won’t use them in my practice. At best, they’re safe, but they won’t come close to achieving the results of custom trays or whitestrips. At worst, accelerating the chemical reaction damages the tooth. This can lead to premature aging and yellowing and may require future dental work if the tooth dies prematurely.
Custom Whitening Trays
For the best way to whiten your teeth, I recommend custom whitening trays, which are made by your dentist after taking impressions of your teeth.
After hydrogen peroxide gel is squirted into the trays, they are placed into your mouth, covering your teeth. The trays keep the whitening gel in place, surrounding all surfaces of the teeth while keeping the gel away from the gums, where it can cause harm.
Once you have these trays made for you, you can use them to repeatedly whiten your teeth for the rest of your life (assuming your teeth don’t move). Just add a peroxide gel (my favorites are Opalesence and Venus White) to the trays and wear them for a few hours or overnight. The gel keeps in the fridge, and you can pop in your trays anytime you need to.
Pros: Custom whitening trays provide the best results in the most cost-effective way. It costs about $250-350 to get your first custom tray, but the gel only costs between $10-30 per tube and it works better than whitening strips.
Risks: If you use a teeth whitening gel that’s too strong and/or you leave your trays in for too long, you risk allowing the the hydrogen peroxide to penetrate too deep into the tooth. This can result in damage of the pulp (the next layer inside the tooth, inside dentin).
Children are especially at risk of damage from whitening trays because they have larger areas of pulp relative to the size of their growing teeth. Damage of the tissue can cause the death of the tooth, tooth pain, or sensitivity.
Whitening strips are small pieces of a flexible plastic called polyethylene. Each flexible strip is coated with a whitening gel that contains hydrogen peroxide or carbamide peroxide, which are both effective teeth whiteners.
To use these products, like Crest Whitestrips, each strip is molded around the teeth—one strip for the top and one for the bottom. This ensures that the peroxide gel in the strips is held up against the teeth so it can seep into the teeth to lighten them.
Whitening strips can be dangerous because they are not custom-fit, so the whitening chemicals come into contact with the gums and other tissues in the mouth.
When whitening strips touch other live tissue, they cause free radical reactions—the same reactions that speed up the aging process.
Whitestrips also tend to provide uneven results. Since strips are 2-D, they do a poor job of getting into the curves in between teeth, which can make your teeth look whiter on their flat surfaces, but yellower at the edges. If you have crooked teeth, even results will be hard—if not impossible—to achieve.
One important note: the whitening gel from strips can cause excruciating pain if it enters a cavity that hasn’t been addressed because of infrequent dental appointments. That means if you haven’t been to the dentist recently, you should stay away from these whitestrips.
There’s also conflicting research about the relationship of hydrogen peroxide to oral cancer. (1, 2) While peroxides are used in whitening trays, too, the gel should never touch gums and it’s much easier to avoid contact of the gel with other surfaces of your mouth.
Pros: Whitening strips are readily available at drugstores and on Amazon; they’re easy to use; and they can generally create results within a few days or weeks.
Risks: Using whitening strips can lead to damage to gums and uneven teeth whitening. There may be danger of increasing your risk of oral cancer if you use peroxide teeth whitening products like whitening strips on a regular basis.
Whitening Methods to Avoid
ZOOM/UV Light/Halogen/LED/Laser Whitening
You’ve probably seen these types of teeth whitening companies stationed at kiosks at the mall. It’s important to point out that the staff running these kiosks often have no healthcare training and no license. Yet, they are dispensing chemicals that could permanently damage your teeth and gums.
Companies such as these get around any legal constraints by having consumers themselves place the whitening tray into their mouths. This means that, under the law, they haven’t technically performed a dental procedure.
This also means that the technicians do not have the appropriate training, nor can you follow-up with them if there are issues after the procedure, like tooth sensitivity or gum damage.
Other teeth whitening kits like HiSmile provide a light that’s supposed to increase the amount teeth are whitened by bleach. But according to research, HiSmile can actually damage teeth, since the UV light may risk damage to the pulp of your teeth.
A mouthwash might contain the right whitening ingredient, but it’s not going to whiten your teeth.
Bleach needs to be held up against the tooth for several minutes or more to seep into the inner part of the tooth and produce a color change. This can only be accomplished if it’s done daily for a few weeks.
Even though the bleach in mouthwash isn’t effective in whitening teeth, there’s still enough of it to impact the inside of the mouth. Every time you rinse, you’re exposing the sensitive inner tissues of your mouth and gums to bleach, potentially causing irreparable harm.
DIY Strawberry or Lemon Pastes
You’ll get results, yes, but at a cost. These DIY pastes “work” because the fruit’s acid wears away the top layer of enamel, revealing whiter enamel underneath.
When enamel is worn away by acid, teeth begin to look worn, old, and discolored. Just like sun tanning means you’ll get wrinkles faster, the acids in these DIY pastes speed up the aging process of your teeth.
This is why I don’t recommend these types of DIY teeth whitening under any circumstances. For surface-whitening (extrinsic whitening), use a whitening toothpaste instead.
Reasons to Avoid Teeth Whitening
If you fall into one of these groups, I recommend you talk with your dentist about your unique case, as teeth whitening might not be right for you:
- Your teeth are already very sensitive
- You have GERD or acid erosion on your teeth
- You have gum recession
- Your gums are sensitive
- You have sensitivity to hydrogen peroxide
- You have cavities
- You have white spot decalcifications (early cavity) which will become whiter and more noticeable after whitening
- You are pregnant or breastfeeding
- You’re under age 18
- You have visible plastic fillings or crowns
Teeth Whitening FAQs
Does dental insurance cover teeth whitening?
No. Whitening is a cosmetic procedure that’s not medically necessary, so it’s very often not covered.
Is whitening ever medically necessary?
No, never. There is no health reason for needing to whiten your teeth.
Most of the yellowing of the teeth is due to aging, and this condition is perfectly normal. Whitening is a personal preference.
How safe is teeth whitening?
There is a significant amount of clinical data that shows whitening gel is safe, particularly bleaching gels with a neutral pH and 10 percent carbamide peroxide. In fact, I personally use a gel with these exact specifications.
My whole family has whitened their teeth using this system, and I’ve tried to mitigate the risks by using custom-made trays, which keep bleaching gel off of the gums and oral tissues.
I think teeth whitening is safe if you take it slow, work with a dentist you trust, and research the bleaching gel you use beforehand.
That said, there are some safety considerations related to teeth whitening that you need to be aware of:
- The free radicals released by peroxide may or may not be associated with a higher risk of oral cancer. None of the studies on this are conclusive, but the absence of evidence doesn’t necessarily mean the absence of harm. (3, 4)
- Some studies have reported damages to enamel which include demineralization or etching, shallow depressions, and slight erosion. This only seems to happen for whitening gels with high concentrations of peroxide with a very low, acid pH. (5)
- Be wary of “research” and claims of super-effective whitening gels. Often, a specific product’s documentation on safety and effectiveness is limited and consists of research sponsored by the manufacturer. I don’t find that to be reliable, as there’s a certainly conflict of interest.
- Teeth whiteners are not classified as drugs, therefore the FDA does not regulate them before they go on the market. Like with supplements, this leaves room for shady companies to sell cheap products until they’re fined by the FDA after the fact. Aim to get a peroxide gel from a reputable, established company.
How can I whiten my teeth naturally?
The best method to naturally whiten teeth is to prevent them from yellowing in the first place.
To do this, be sure to wear a mouthguard during sports and other extreme activities, as damaged teeth tend to age—and yellow—prematurely.
You should also avoid consuming highly pigmented foods and drinks (like, coffee, tea, wine, and food coloring) that can cause staining. If you can’t avoid them altogether, be sure to at least drink water during and after consumption.
In general, drinking plenty of water throughout the day is a good way to prevent staining.
If staining has already occured, a good, stain removing, electric toothbrush like the Goby brush is the best whitening option.
As an added bonus for choosing a Goby toothbrush, you can purchase a subscription plan that delivers replacement brush heads right to your door every one to three months, so you never have to remember to purchase them again.
Why and how do teeth yellow and darken?
Here are a few factors that cause yellowing and darkening of the teeth:
Biology: Adult teeth are naturally grayer and yellower than baby teeth. With so many images of sparkling white teeth online and in magazines, people whiten their teeth in hopes of getting the same results. But we forget—teeth are not naturally that white.
Staining: Your teeth might also appear yellow because of staining from years of consuming wine, tea, coffee, tobacco, and other highly pigmented products. By rinsing with water during and after the consumption of staining foods and drinks, you can do a lot to protect the color of your teeth.
Aging: This type of yellowing is much deeper than the superficial staining caused by drinking coffee or wine. As we age, the organic tissue deep inside the tooth, called dentin, begins to yellow. This yellowed pigment is then refracted out through the enamel, giving the entire tooth a yellow color.
If your teeth appear yellow when you look in the mirror, it’s likely a combination of all three of these factors. I do want to stress, however, that some yellowing is totally natural and nothing to worry about.
Final Thoughts on Teeth Whitening
While many people aim for the sparkliest smile they can achieve, whiter teeth don’t actually mean healthier teeth. That said, there’s nothing wrong with trying a safe teeth whitening method if you’re not happy with the color of your teeth.
First, you should know what you’re going for.
Do you have stains on your teeth? If you’re a heavy coffee, kombucha, tea, or wine drinker, you can probably benefit from extrinsic whitening (also known as stain removal).
Are your teeth yellowing due to age, trauma, or poor diet? This yellow or grayish hue can only be corrected by intrinsic whitening by bleaching the teeth with peroxide.
The safest and best teeth whitening kit is a stain-removing toothbrush and toothpaste. Here are the ones I use (just remember to use the toothpaste for only two weeks or less at a time):
Jason Natural Powersmile Whitening Toothpaste
Goby Sonic Toothbrush
For intrinsic whitening, go to the dentist to be fitted for a custom whitening tray. You can buy the replacement gel and use the same tray for as long as your teeth stay in the same position. I like Opalesence Teeth Whitening Gel.
Whitening methods you might try on occasion (but very infrequently) include:
- Professional teeth whitening by your dentist (often accompanied by heat or light)
- Whitening strips (like Crest Whitestrips)
I would avoid these whitening methods entirely:
- ZOOM/UV Light/Halogen/LED/Laser Whitening
- Whitening mouthwash
- DIY strawberry or lemon pastes
What other questions do you have about teeth whitening? Just ask me a question and I’ll be sure to add the answer here!
Acid: Softens the surface of tooth enamel thanks to its low pH, causing teeth to become worn, sensitive, and prone to cavities. Acidic foods and drinks include citrus fruit and juice, soda, coffee, and wine.
Reducing the acids in your diet with alkaline foods like green veggies, as well as swishing with water after consuming acidic foods and drinks, can help protect your teeth.
Abrasion: The scraping or wearing away of tooth enamel by abrasive compounds, usually in toothpaste. Larger, more dangerous abrasions may also happen when you expose your teeth to substances like acid that break down enamel, or when you use a toothbrush head that’s too old.
Carbamide peroxide gel: A type of whitening gel. It penetrates the tooth at a slower rate and can aid in patient comfort and compliance by reducing sensitivity. Contains hydrogen peroxide.
Hydrogen peroxide gel: Another type of whitening gel. Hydrogen peroxide is what actually whitens your teeth. Carbamide peroxide first breaks down into hydrogen peroxide before having whitening power.
Gum recession: Gum recession is when gums pull down, away from the tooth, after healing from inflammation. Receding gums aren’t pretty and they lead to tooth sensitivity because it causes the root of the tooth starts to become exposed.
Gum recession is irreversible. It’s permanent and no surgery can fix it, although new techniques are being developed regularly.Read Next: 5 Essential Habits for Keeping Your Teeth Clean and Healthy
- Weitzman, S. A., Weitberg, A. B., Stossel, T. P., Schwartz, J., & Shklar, G. (1986). Effects of hydrogen peroxide on oral carcinogenesis in hamsters. Journal of Periodontology, 57(11), 685-688. Abstract: https://www.ncbi.nlm.nih.gov/pubmed/3104570
- Munro, I. C., Williams, G. M., Heymann, H. O., & Kroes, R. (2006). Use of hydrogen peroxide‐based tooth whitening products and its relationship to oral cancer. Journal of Esthetic and Restorative Dentistry, 18(3), 119-125. Full text: https://s3.amazonaws.com/academia.edu.documents/42951246/Use_of_Hydrogen_Peroxide…
- Kugel, G., Papathanasiou, A., Anderson, C., & Ferreira, S. (2006). Clinical evaluation of chemical and light-activated tooth whitening systems. Compendium of continuing education in dentistry (Jamesburg, NJ: 1995), 27(1), 54-62. Abstract: https://www.ncbi.nlm.nih.gov/pubmed/16454016
- Buchalla, W., & Attin, T. (2007). External bleaching therapy with activation by heat, light or laser—a systematic review. Dental materials, 23(5), 586-596. Abstract: https://www.ncbi.nlm.nih.gov/pubmed/16820199
- Shannon, H., Spencer, P., Gross, K., & Tira, D. (1993). Characterization of enamel exposed to 10% carbamide peroxide bleaching agents. Quintessence international, 24(1). Abstract: https://www.ncbi.nlm.nih.gov/pubmed/8511257