Less than a fifth of toothbrushes follow standards – 04/14/2023 – Equilibrium and Health

No zigzag bristles, interspersed with erasers or distributed in uneven arrangements. A proper toothbrush is simple: it requires at least 18 tufts, each with 80 rounded, polished bristles. Even so, of 345 copies purchased in 26 cities in São Paulo, only 60 (17.4%) had these characteristics, reveals a survey carried out at the Faculty of Public Health at USP.

The study, conducted by Sônia Regina Cardim de Cerqueira Pestana and supervised by Paulo Capel Narvai, points out that only one of the seven manual toothbrushes for babies was adequate. Among children’s models, 14 of the 105 evaluated units followed the parameters and, among those intended for adults, 45 were adequate, against 188 inadequate.

The analysis was performed at two levels: with the naked eye and with a microscope. In the first part, the shape of the handle and head of each specimen was examined, and more than 70% of the sample was considered to be in ideal standards.

In the second part, the bristles were observed under a microscope — and that’s when the problems appeared. Most products had fewer bristles than necessary and dimensions different from those recommended: length between 9 mm and 10 mm and diameter of 0.18 mm for adults and 0.13 mm for children

Furthermore, few bristles had polished and rounded ends. Most of the ends were straight and ragged.

“Millimeters of difference in the format of the handle or in the head do not interfere with suitability. They can affect ergonomics, but do not make the instrument unsuitable for use. What is decisive for making the product suitable are the bristles, their tip type and the quantity”, emphasizes the researcher, who works at Cecol (Collaborating Center of the Ministry of Health in Oral Health Surveillance) and is a professor of dentistry at the University of São Caetano do Sul.

Pestana says that the investigation began in 2017, when she started her doctorate under Narvai’s guidance. He had an old desire to study toothbrushes, an instrument that, despite its widespread use, is the subject of little research, and she liked the proposal.

The first phase consisted of a bibliographic survey, which confirmed the existence of a limited number of studies. Then came the analysis of the norms referring to oral health instruments. “By studying the standards, we realized how fragile they are and this increased our desire to research brushes”, he says.

Next, 24 cities in São Paulo were drawn, six of each size. In addition to these, Pestana added the smallest municipality in São Paulo, Borá, with an estimated population of 839 people, and the capital, with 12 million inhabitants, totaling 26 locations.

She traveled to each of the municipalities and visited pharmacies, supermarkets and convenience stores to purchase the different models. Excluding the repeated brushes, it reached the sample with 345 units.

Pestana defined the analysis categories based on the minimum standard pointed out by Charles Bass, an American pioneer in the study of toothbrushes, and started the survey that indicated the inadequacies.

“Today we have brushes with 500 to 7,000 bristles on the market. So I can have a brush with 700 bristles that will last very little or one with 6,000 bristles with a diameter much smaller than the standard”, he says. “And that has nothing to do with price or brand.”

It also took into account the rules in force at the time and, in the revised version of the study, included the new resolution of March 2022.

“The standard does not present the necessary characteristics in a more forceful way and states that 80% of the bristles applied to the brush must have a minimum acceptable finish. It is not acceptable that 20% are not rounded, it is a very large margin”, he criticizes.

According to the teacher, the differences in the bristles do not alter the removal of bacterial plaque: all brushes have this ability. However, inadequate bristles can cause microfissures in the gums, causing pain after brushing, and lead to wear on the tooth enamel, which after a prolonged period can cause hypersensitivity. “We consider the norm fragile and this is serious because the consumer does not know what he is buying.”

According to Anvisa (National Health Surveillance Agency), toothbrushes are products exempt from registration and their sale in the country is subject to prior communication through notification and compliance with the technical requirements described in the resolution.

The body states that the 2021-2023 regulatory agenda does not provide for changes in the current resolution, but the responsible technical area will evaluate the possibility of including a revision of the standard in the 2024-2026 agenda.

The agency also says that the results of the study conducted at USP will be evaluated and highlights that any problems with cosmetic products, including toothbrushes, can be notified. “Such information is important for the monitoring work”, he emphasizes.

Notifications can be made on the Anvisa page.