Are Whitening Strips Bad for Your Teeth? Dentists Explain

These days, it seems that every public figure has the same blinding smile. The fascination with pearly whites arguably dates back to the Golden Age of Hollywood, when La La Land dentist Charles Pincus was creating tooth caps for the likes of Judy Garland, James Dean and Shirley Temple. Today, veneers easily run between $1,000 to $8,000 a tooth. So what are those whose dental budget is less than $100k (or let’s be honest, $100) to do? Whitening strips are a popular over-the-counter fix. But they contain bleach, which makes us wonder: Are whitening strips bad for your teeth? Two dentists weigh in. Read on before reaching for that box of strips.

• Dr. Edward Camacho, DDS, is a San Antonio, Texas-based dentist with over 40 years of experience. During that time, he has performed thousands of cosmetic, restorative and general dentistry procedures. He is an active member of the American Dental Association, Clinical Foundation of Orthopedics and Orthodontics and American Academy of Cosmetic Dentistry, among other organizations. Dr. Camacho completed his studies at the University of Texas Health Science Center at San Antonio.
• Dr. Erin Fraundorf, DMD, MSD is the found of BOCA Orthodontic + Whitening Studio in St. Louis, Missouri. She specializes in orthodontics and dentofacial orthopedics and is a member of the American Association of Orthodontists and the American Dental Association. Dr. Fraundorf completed her training at St. Louis University.

There are many reasons why your pearly whites may look less than, well, white. Dr. Camacho explains that teeth are susceptible to two types of stains: intrinsic and extrinsic. The former, he says, occurs during tooth formation and causes discoloration. External factors like food (coffee, wine, citrus, soda), lifestyle habits (smoking), medication (liquid iron), supplements (turmeric, saffron, curry) and aging influence the latter.

Dr. Fraundorf adds that factors like genetics play a part, too. “Teeth have a genetic component that you inherit from your family,” she says. That includes enamel and dentin. “If the enamel (the outer layer of your teeth) is very thin or more see-through, the next tooth layer called the dentin will show through it more prominently. Dentin is a yellow to brownish color. If your enamel is thick and has more opacity, the yellow tint of the dentin will show through less.”

Both dentists also note that tetracycline antibiotics can cause intrinsic stains. If a child takes this type of antibiotic before age 8, or their biological mother took it while pregnant, the person could end up with permanently stained teeth as adults.

According to Dr. Fraundorf, there are two methods for teeth whitening, mechanical and chemical. “Mechanical teeth whitening [removes] surface stains via a physical means,” she says. That includes tooth brushing, whitening toothpaste and professional cleanings. Meanwhile, chemical whitening “is based on the application of a whitening solution (either a carbamide peroxide or hydrogen peroxide) to your teeth. These whitening agents penetrate your teeth and [cause] a chemical reaction, oxidizing stains, therefore removing color and making your teeth appear whiter.”

Chemical whitening can be done at home or at the dentist’s office, though Dr. Fraundorf says that there will be a marked difference in the concentration of the products and application. “Something from the drugstore will be a lower concentration and something from the dentist much higher,” she says.

If doing an at-home treatment, both dentists advise applying whitening products after you’ve brushed your teeth, so there isn’t a barrier of plaque that can hinder the absorption of bleach.

“Do not exceed 30 minutes of wear time. Rinse [after] removing them and do not swallow bleaching solution,” Dr. Camacho cautions. Dr. Fraundorf also recommends easing the products into your routine to minimize the chances of sensitivity and keeping it away from your gums.

The number one benefit of whitening strips is that they’re affordable. While veneers can run up to $8,000 per tooth, a box of Crest Whitestrips are $30 at Amazon.

However, Dr. Fraundorf notes that there are trade-offs when it comes to at-home vs in-office treatments. Because professional teeth whitening gels are stronger, you may be able to get away with a visit to the dentist once a year, while over the counter products may require consecutive daily use per kit.

No matter which route you choose, the end benefit is often the same: a confidence boost.

Before you go running off to Target or hitting “add to cart” online, there are a couple caveats. “Whitening strips are most effective on younger people,” Dr. Camacho says. “Someone in their twenties hasn’t had decades of coffee, tobacco use, wine and/or tea consumption.” Older folks’ teeth have had a longer period of time to absorb stains, making them more difficult to remove. In this case, he advises consulting a dentist and having the stain removal done professionally.  

Additionally, he explains that some people are born with translucent teeth, meaning the edge of the enamel appears clear. “This means that there is not very much pigment in the enamel. Attempting to whiten/bleach the teeth removes what little color pigment there is. Instead of getting whiter, the teeth become more translucent and start to look gray or blue.”

A simple test will tell you if your teeth are translucent. Dry your teeth, then hold a white paper towel behind them, Dr. Camacho instructs. If your teeth appear much whiter than the paper towl, then you have clear enamel. In this case, he recommends the person opt for veneers instead. This brings up another point Dr. Fraundorf raises. Should you want to have whitening work done in the future, things like veneers and crowns can’t be whitened. Deep stains will also be unaffected by treatment but can be spot treated. She cautions that teeth whitening isn’t advised for those under the age of 12, those with untreated dental issues or those who are pregnant.

Common ingredients in whitening strips include hydrogen and carbamide peroxide and sodium hydroxide. These all work to lift stains off the teeth, Dr. Camacho says. There have been concerns about the effects of bleaching agents on teeth, notably regarding hydrogen peroxide and sodium hydroxide. Concerning the latter, Dr. Camacho explains, “By itself, it is harmful in the body. However, in such a small amount, it is not considered harmful. Bleaching products are not designed to be swallowed, but only applied topically to the surface of the teeth and then rinsed off.” This is why he advises rinsing your mouth thoroughly after applying whitening strips.

Regarding hydrogen peroxide, a 2019 study conducted by Stockton University found that it could have negative effects on dentin, which is the tissue below the enamel. Research showed reduced collagen in teeth that had been treated. However, they concluded that there is currently insufficient data to determine if the damage is permanent, and they didn’t explore whether the collagen could be regenerated.

Bottom line: If you’re trying whitening strips, it’s best to proceed with caution. Like Dr. Fraundorf advises above, ease your way into it and consult your dentist if you’re experiencing adverse reactions.

The truth is, there isn’t any published literature supporting the efficacy of natural teeth whitening agents, Dr. Camacho says. Both he and Dr. Fraundorf also caution against the popular use of charcoal.

“[It] actually causes more damage to your teeth and gums than anything else,” Dr. Fraundorf says. “Charcoal toothpastes use large abrasive particles [to mechanically whiten teeth]. These particles, like sandpaper, are used to roughen the surface to remove stains adhered onto the outer surface of your teeth.”

Her advice for those seeking brighter smiles is to get serious about their oral hygiene. “I recommend my patients use a toothpaste with nano-hydroxyapatite, an electric toothbrush, manual floss and water flosser. Staying on top of your oral hygiene routine will help blast away the staining particles your teeth are exposed to every day before they penetrate inside your teeth and become intrinsic stains.” And if you still want to up the wattage? Book that dentist appointment.