You may have come across videos in social media showing how you can whiten your teeth simply by brushing them with a fruit and baking soda mixture. Researchers have found that such a do-it-yourself method does not actually work.
The strawberry and baking soda formula produced no whitening, other than removing superficial debris, the findings showed.
"The only benefit of the do-it-yourself method (strawberries and baking soda) is while it seems to make your teeth look whiter, they look whiter because you are just removing plaque accumulation on your teeth," said So Ran Kwon, sole author of the study and associate professor at the University of Iowa in the US.
"You really want something that penetrates into your teeth and breaks down the stain molecules. If you do not have that, you get just the superficial, and not the whitening from the inside, which was what you really want," Kwon aded.
The main reason why strawberries do not work as teeth whiteners is their chemistry.
They may taste great, but they are utterly lacking in hydrogen peroxide and carbamide peroxide, key ingredients in tooth-whitening products, according to the American Dental Association.
Apples and lemons, also popularly advocated as tooth whiteners, have no hydrogen peroxide and carbamide peroxide, suggesting their effectiveness as tooth whiteners would be limited as well, although Kwon did not directly test those fruits.
For the study, the researcher compared a homemade strawberry-baking soda recipe with other remedies, such as over-the-counter products and professional whitening.
The teeth brushed with the strawberry-baking soda mixture showed no real whitening, based on two well-known colour-measurement tests and evaluations with a spectrophotometer.
All other methods produced discernible whitening in the observational and instrumental tests, the study found.
The findings appeared in the journal Operative Dentistry.
