The rising prevalence of dental erosion and dentin hypersensitivity has led to the emergence of toothpastes designed to treat these problems. While no such toothpastes existed 20 years ago, many brands are offered today. Yet researchers note that none of the nine toothpastes they analyzed could mitigate 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 in Brazil and first author of the study.
In fact, all of the tested toothpastes caused different amounts of enamel surface loss, and none of them protected against enamel erosion and abrasion. The researchers noted that these toothpastes perform a function but that they should be used as a complement, not as a treatment, strictly speaking. These issues require treatment prescribed by a dentist, use of an appropriate toothpaste, and a change in lifestyle, especially diet, João-Souza said.
“Dental erosion in multifactorial. It has to do with brushing and, above all, with diet. Food and drink are increasingly acidic as a result of industrial processing,” João-Souza said.
Dental erosion is a chronic loss of dental hard tissue caused by acid without bacterial involvement, unlike caries, which is related to bacteria. When acid is associated with mechanical action such as brushing, it results in erosive wear. In these situations, patients typically experience discomfort when they eat or drink something hot, cold, 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 Ana Cecília Corrêa Aranha, PhD, João-Souza’s supervisor and coauthor of the study.
“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,” Aranha said.
The researchers 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 study simulated the effect of brushing once a day with exposure to an acid solution for five consecutive days on tooth enamel. It 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 said.
The physical analysis consisted of weighing the abrasive particles in the toothpastes, measuring their size, and testing their wettability, which is 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.
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,” said Aranha.
The researchers plan to begin a more specific in vivo study that will also include pain evaluations. The study, “Chemical and physical factors of desensitizing and/or anti-erosive toothpastes associated with lower erosive tooth wear,” was published by Scientific Reports.