WATCH: We spoke to a dental hygienist about the #hydrogenperoxide #toothwhitening trend

Your quest for whiter teeth could result in burned gums, damaged enamel and a splotchy, uneven smile.

Emma Jones 5 minute read January 11, 2022

On TikTok, what’s old is new again, especially as another hydrogen peroxide rumour comes bubbling to the surface. Dental professionals, however, warn that using a DIY whitening product without first seeking the advice of an expert can lead to splotchy results or damaged gums.

Proponents are diluting hydrogen peroxide with water, and then dabbing the mixture on their teeth with a Q-tip. After a few minutes, they use toothpaste to brush the solution off. In a video that has 2.4 million views, TikToker @valentinachang5 explains she brushes her teeth with a mixture of hydrogen peroxide and baking soda to get white teeth.

Anaida Deti, a Registered Dental Hygienist and CEO of DentalX, warns that whitening teeth is not as simple as adding some peroxide to your oral care routine.

“[A dental professional will] do a proper checkup,” she says. “We make sure that…we have all the medical history to make sure that it’s not dangerous. We check dental health and made sure that the teeth whitening is proper for you and then we suggest the proper treatment, and then you decide what you want to do.

While many over-the-counter teeth whitening kits will often contain three to 10 per cent hydrogen peroxide, Deti says that higher concentrations should be used very carefully and only applied by professionals. High concentrati

ons of peroxide has the potential to damage the tooth enamel, burn gums, lips or the tongue, and can cause nausea or other complications, if swallowed.

Young woman's reflection in mirror holding toothbrush, smiling, portrait

The goal is healthy teeth, not white teeth. GETTY

Tasneem Pirani, Practice Advisor with the College of Dental Hygienists of Ontario, also explains that the teeth are not a uniform surface and a DIY whitening product may interact differently with different surfaces, resulting in a smile of different shades.

“Not everybody is a good candidate for whitening, so it depends on the condition of the teeth and the gums,” says Pirani. “…For example, if you have fluorosis — a type of grey or brown stain that can be from having too much fluoride in your water when you are young and your teeth are developing — those types of stains are not going to change with any whitening product.

“If you have, for example, a crown or a veneer, or a big white filling on a front tooth, if you put a whitening product on there it will not change the colour of that area.”

Both professionals also warn that putting hydrogen peroxide on an exposed root, often caused by a recession when the gums pull back exposing the root of the tooth, can result in prolonged tooth sensitivity.

Deti says that the perfect white movie star smile so many people aim for can only be achieved by veneers, which can run upwards of $1000 per tooth. Instead of aiming for flawless white teeth at home, she recommends focusing on tooth health, which can be reasonably obtained by brushing twice a day, flossing once per day, and swishing with salt water.

“Nobody’s teeth are naturally going to be paper white,” says Pirani.

Tooth whitening: results may vary

One study that looked at the impact of different whitening treatments on tooth enamel found that the teeth were effectively whitened regardless of the peroxide concentration (samples ranged from 10 per cent carbamide peroxide — a bleaching agent that breaks down into hydrogen peroxide and urea — to 40 per cent hydrogen peroxide). However, products that contained lower peroxide concentrations, and thus, had to be left on teeth longer to achieve similar results, resulted in more damage to the enamel.

Interestingly, for all the products reviewed in this study, the most significant whitening occurred after the first bleaching treatment and did not significantly improve after subsequent treatments.

These findings were somewhat echoed in a different study which compared the effectiveness of a gel containing 10 per cent carbamide peroxide against a 1.5 per cent hydrogen peroxide solution (mouthwash). Researchers found that while both substances significantly whitened the teeth, the 10 per cent gel resulted in greater brightness — although it is unclear if this is due to the concentration of the peroxide or the substance itself (gel versus a solution).

Better first impressions

And while the quest for whiter teeth sounds a lot like yet another indication of personal vanity, studies have shown that the more pearly white your teeth are, the more positively you are perceived.

Researchers at King’s College Dental Institute in the U.K. had participants look at photos and then rate the person on assumed social competence, intellectual ability, psychological adjustment, and relationship satisfaction. They found that whiter teeth correlated with more positive ratings across all categories.

Still, the consensus among the experts is that whitening products DIY or otherwise should be handled with care. The Canadian Dental Association (CDA) warns that the long term effects of multiple bleaching treatments over many years is unknown. Pirani says that she only recommends her patients use evening whitening toothpastes for a set amount of time before switching back to a toothpaste designed for every day.


Emma Jones is a multimedia editor with Healthing. You can reach her at or on Twitter @jonesyjourn