The toothpaste aisle, like so much of life, is filled with plenty of claims that seem too good to be true. One of these false promises, a recent study in Scientific Reports suggests, might be that toothpaste can stop our teeth from eroding.
Toothpastes that say they stop erosion aren't getting the job done better than your typical tube of paste, a study says. Photo: Scott Ehardt (Wikimedia Commons)
Researchers in Brazil and Switzerland worked together to test nine brand-name toothpastes. The toothpastes, all commonly found in Brazilian or European stores, included regional brands such as Elmex as well as those internationally sold such as Sensodyne. For five days, once a day, they doused samples of enamel taken straight from human teeth in citric acid, swished them around in toothpaste slurry and artificial saliva and had them brushed by toothbrushes.
After they were rinsed and dried, they measured how much enamel eroded off the surface.
The very act of brushing our teeth with toothpaste causes enamel erosion, even as it helps prevent bacteria from building up as plaque. This erosion can eventually cause the bony tissue underneath the enamel, known as dentine, to become exposed to the open air, leading to hypersensitivity and creating the opportunity for cavities.
But by experiment's end, the toothpastes branded as either anti-erosive or desensitising failed to prevent erosion significantly better than the plain one (Colgate Cavity Protection) the researchers used. All the brands were fluoridated.
"The test showed that some [toothpastes] caused less surface loss than others, but they all resembled the control toothpaste [for] this criterion," said senior author Ana Cecília Corrêa Aranha, a dental researcher at University of São Paulo's School of Dentistry, in a statement.
The study isn't the first to blow up the idea that anti-erosive toothpastes are anything special compared to the generic stuff. But Aranha's team did find some factors that might promote better erosion protection.
Toothpastes that contained tin, had higher concentrations of calcium and phosphate, or only had small particles, for instance, were associated with less surface loss. Fluoride, though having plenty of other benefits for teeth, such as helping prevent cavities and tooth decay, didn't have any big influence on enamel erosion, contrary to what some earlier research has suggested.
Ultimately, the researchers believe the findings affirm that there's no one single step we can take to keep our teeth healthy from either bacteria or enamel loss.
"Dental erosion is multifactorial. It has to do with brushing, and above all, with diet," Aranha said, referencing research that's long shown how acidic foods like soft drinks can speed along erosion, especially when coupled with harsh toothbrushing. "Food and drink are increasingly acidic as a result of industrial processing."
Not all hope might be lost, though, if you're trying to find a toothpaste that can do something meaningful about erosion. In a statement made to Gizmodo, the American Dental Association said that it had awarded its first seal of acceptance for a product in the enamel erosion category last November, the Crest brand "Pro-Health Advanced, Deep Clean Mint" toothpaste (it was not one of the brands included in the current study).
"To earn the ADA Seal of Acceptance in this category, safety and effectiveness must be demonstrated via two independent clinical studies assessing the product's ability to prevent or reduce enamel erosion from dietary acids," the organisation said.
"The ADA supports additional research on dental erosion. Patients should talk to their dentist about what dental products will work best for their specific needs," it added.
The researchers next hope to study how to better protect against erosion in real-life test subjects. In the meantime, brush gently, and use a toothbrush with bristles labelled as "soft."