Analysis of 9 toothpastes found that none protects enamel or prevents erosive wear
Fundação de Amparo à
Pesquisa do Estado de São Paulo
The rising prevalence
of dental erosion and dentin hypersensitivity has led to the emergence of more
and more toothpastes on the market that claim to treat these problems. While no such toothpaste existed 20 years ago, today, many brands with different attributes are being offered.
However, a study
conducted at the University of Bern in Switzerland with the participation of a
researcher supported by a scholarship from the São Paulo Research Foundation --
FAPESP showed that none of the nine analyzed toothpastes was capable of mitigating
enamel surface loss, a key factor in tooth erosion and dentin hypersensitivity.
"Research has shown that dentin must be exposed with open tubules in order for there to be hypersensitivity, and erosion is one of the causes of dentin exposure. This is why, in our study, we analyzed toothpastes that claim to be anti-erosive and/or desensitizing," said Samira Helena João-Souza, a PhD scholar at the University of São Paulo's School of Dentistry (FO-USP) in Brazil and first author of the article.
According to an
article published in Scientific Reports, all of the tested
toothpastes caused different amounts of enamel surface loss, and none of the
toothpastes afforded protection against enamel erosion and abrasion.
The authors of the
study stressed that these toothpastes perform a function but that they should
be used as a complement, not as a treatment, strictly speaking. According to
João-Souza, at least three factors are required: treatment prescribed by a
dentist, use of an appropriate toothpaste, and a change in lifestyle,
especially diet.
"Dental erosion
is multifactorial. It has to do with brushing, and above all, with diet. Food
and drink are increasingly acidic as a result of industrial processing,"
she said.
The researcher
highlights that dental erosion is a chronic loss of dental hard tissue caused
by acid without bacterial involvement -- unlike caries, which is
bacteria-related. When it is associated with mechanical action, such as
brushing, it results in erosive wear. In these situations, patients typically
experience discomfort when they drink or eat something cold, hot or sweet.
"They come to the
clinic with the complaint that they have caries, but actually, the problem is
caused by dentin exposure due to improper brushing with [a] very abrasive
toothpaste, for example, combined with frequent consumption of large amounts of
acidic foods and beverages," said Professor Ana Cecília Corrêa Aranha,
João-Souza's supervisor and a co-author of the article.
In our clinical work,
we see patients with this problem in the cervical region between [the] gum and
tooth. The enamel in this region is thinner and more susceptible to the
problem," she added.
Methodology
The scientists tested
eight anti-erosive and/or desensitizing toothpastes and one control toothpaste,
all of which are available from pharmacies and drugstores in Brazil or Europe.
The research simulated
the effect of brushing once a day with exposure to an acid solution for five
consecutive days on tooth enamel. The study used human premolars donated for
scientific research purposes, artificial saliva, and an automatic brushing
machine.
"We used a
microhardness test to calculate enamel loss due to brushing with the
toothpastes tested. The chemical analysis consisted of measuring toothpaste pH
and levels of tin, calcium, phosphate and fluoride," João-Souza explained.
The physical analysis
consisted of weighing the abrasive particles contained in the toothpastes,
measuring their size, and testing wettability -- the ease with which toothpaste
mixed with artificial saliva could be spread on the tooth surface.
"During brushing
with these toothpastes mixed with artificial saliva, we found that the
properties of the toothpastes were different, so we decided to broaden the
scope of the analysis to include chemical and physical factors. This
[broadening] made the study more comprehensive," João-Souza said.
Statistically similar
All of the analyzed
toothpastes caused progressive tooth surface loss in the five-day period.
"None of them was better than the others. Indication will depend on each
case. The test showed that some [toothpastes] caused less surface loss than
others, but they all resembled the control toothpaste [for] this criterion.
Statistically, they were all similar, although numerically, there were
differences," Aranha said.
"We're now
working on other studies relating to dentin in order to think about
possibilities, given that none of these toothpastes was found capable of
preventing dental erosion or dentin hypersensitivity, which is a cause of
concern."
The researchers plan
to begin a more specific in vivo study that will also include pain evaluations.