Article 77 of the Regulations on the Supervision and Administration of Cosmetics states, “Toothpaste shall be administered with reference to the provisions of these Regulations concerning ordinary cosmetics. After evaluating the efficacy of toothpaste in accordance with national and industry standards, the toothpaste filer may claim that the toothpaste has the efficacy of preventing caries, inhibiting plaque, resisting dentin sensitivity, and alleviating gum problems.”
Toothpaste is a necessity in our daily life. Understanding the types of toothpaste and its effects is very important for scientific purchase of toothpaste and maintaining oral health.
Toothpastes have different effects and applicability
China’s recommended national standard GB/T 8372-2017 “Toothpaste” defines toothpaste as a paste-like substance consisting of a mixture of friction agents, moisturising agents, thickening agents, foaming agents, aromatisers, water and other additives (including efficacious ingredients used to improve the state of oral health) as the main raw materials. This definition describes the main components of toothpaste and the physical properties of the product. The Measures for the Supervision and Administration of Toothpaste (Exposure Draft) suggests that toothpaste is a solid or semi-solid preparation that is applied by friction to the surface of human teeth and the surrounding tissues for the purpose of cleansing, beautifying and protecting. It defines toothpaste from four aspects: mode of action, site of action, purpose of use and physical properties of the product, and excludes oral products such as mouthwash, making the boundary scope of toothpaste clearer.
The Specification for Toothpaste Filing Information (Exposure Draft) classifies the efficacy of toothpaste into nine categories, including basic cleaning, anti-caries, plaque inhibition, anti-dentin sensitivity, reduction of gum problems, whitening, tartar resistance, reduction of halitosis, and other efficacy. At the same time, the draft will be the use of toothpaste population is divided into adults and children, of which the age of children for the age group of 6 months ~ 12 years old, children’s toothpaste can only be claimed to have the basic cleaning class and anti-caries class effect.
Currently, toothpastes on sale are available in a variety of product types depending on their efficacy categories and applicability to different groups of people.
Toothpaste only removes exogenous staining
With the improvement of living standard, people pay more and more attention to their own image. Having a mouthful of healthy and white teeth can add points to the image, teeth whitening has become a topic of increasing concern.
Nowadays, there is a wide range of toothpastes on the market that claim to whiten teeth, but can these products really whiten teeth? What is the mechanism of teeth whitening?
The causes of yellowing of teeth are classified into exogenous and endogenous staining. Exogenous staining is mainly caused by pigments brought in by daily diet or pigments produced by bacteria in the mouth depositing on the surface of the teeth. For example, if you drink coffee, cola, tea, red wine or smoke for a long period of time, some of the pigment will be deposited in the tiny depressions on the surface of the teeth when the substance passes through the mouth and the teeth, making the teeth yellow. Exogenous staining is relatively easy to remove.
Endogenous staining is mainly caused by a change in the colour of the enamel or dentin in the deeper layers of the teeth. For example, tetracycline teeth are yellowed as a result of taking the antibiotic tetracycline for a long period of time due to a disease, which causes the pigment to be deposited in the dentin. In addition, tooth discolouration caused by dental fluorosis and pulp necrosis also belongs to endogenous staining. Generally speaking, endogenous tooth discolouration is difficult to remove by brushing.
Industry standard QB/T 2966-2014 “efficacy toothpaste” stipulates that, in addition to the basic functions, the efficacy of toothpaste should be supported by efficacy evaluation report, efficacy evaluation report, including clinical evaluation report and laboratory evaluation report; involving caries prevention, plaque inhibition, anti-dentin sensitivity, alleviate the effectiveness of the gums problem should be in accordance with the evaluation method of the WS/T 326 issued clinical evaluation report. Fluoride as an anti-caries components of toothpaste, may not do anti-caries effect of clinical evaluation. The toothpaste supervision and management measures (draft for comments), “toothpaste filing information specification” (draft for comments) follows the above provisions.
After the efficacy evaluation of the whitening toothpaste on the teeth of exogenous staining has a certain role in removing, can achieve the effect of whitening teeth; due to endogenous staining caused by the yellowing of the teeth, the consumer should be combined with their own needs and characteristics, in the stomatologist under the guidance of the choice of whitening products and methods of whitening teeth.
Fluoride toothpaste does not cause dental fluorosis
Currently, there are three types of toothpaste products on the market that are roughly related to “fluoride”, namely fluoride-containing anti-caries toothpaste, non-fluoride-containing anti-caries toothpaste, and non-fluoride-containing toothpaste that does not contain fluoride and does not claim to be anti-caries.
Fluoride-containing anti-caries toothpaste refers to toothpaste formulated with fluoride, and fluoride is mainly used to prevent caries and strengthen teeth. Fluorides that can be used in toothpastes include sodium fluoride, stannous fluoride, and sodium monofluorophosphate.
Non-fluorinated anti-caries toothpaste refers to a toothpaste that has been verified in human trials to have anti-caries efficacy even though fluoride has not been added to the product formulation.
Toothpastes that do not contain fluoride and do not claim to be caries-preventive do not have caries-preventive effects, and consumers should choose them according to their actual needs.
Dental caries, commonly known as tooth decay, refers to the process of demineralisation of hard tissues of the dentin caused by the metabolic acid production of bacteria in the oral cavity through food debris and other metabolism, followed by the production of cavities, which is a dental disease with a high incidence rate. Fluoride in toothpaste can prevent caries by reducing the solubility of tooth enamel, promoting remineralisation of teeth and reducing caries-causing bacteria and their acid production.
The role of fluoride in toothpaste in preventing dental caries has been clearly verified by the results of the quantitative-effect relationship. China’s recommended national standard GB/T 8372-2017 “toothpaste” stipulates that the minimum starting amount of fluoride in toothpaste to play the effect of caries prevention is 0.05% (mass fraction, the same below), and the upper limit of fluoride added in children’s toothpaste is 0.11%, and the upper limit of fluoride added in adult toothpaste is 0.15%. Therefore, as long as the fluorine content meets the above addition requirements, fluorine-containing anti-caries toothpaste can be exempted from human efficacy evaluation.
There are media reports that the use of fluoride toothpaste will cause people to suffer from dental fluorosis and osteofluorosis, causing consumers to talk about “fluoride”; some merchants claimed in their advertisements that the toothpaste they sell “does not contain fluoride, and it is safer”, which has further caused consumers to have misunderstandings. In fact, fluorosis, dental fluorosis, osteofluorosis and other symptoms will only occur when excessive fluorine is ingested, and consumers who buy toothpaste through regular channels and brush and rinse their teeth correctly will not experience fluorosis and other symptoms.
Mechanism of action of whitening toothpaste
Currently, there are three main whitening mechanisms for toothpastes on the market that claim to have whitening effects.
One is to whiten the teeth through oxidation reaction, i.e. the chemical ingredients in the toothpaste have a bleaching effect with the stains on the tooth surface to remove the tooth colouring. Commonly used chemical bleaching ingredients are hydrogen peroxide, urea peroxide, polyphosphates and so on. These whitening toothpastes have a good teeth whitening effect, but there is a risk of damaging the enamel and making the teeth sensitive and fragile. It is generally accepted that toothpastes containing more than 3% hydrogen peroxide (in terms of hydrogen peroxide present or released) no longer fall into the category of toothpaste in the traditional sense. Products such as teeth whitening gels and dental bleaches that can contain up to 10% to 20% peroxide are medical devices, which have a bleaching effect on endogenous staining, but have a high safety risk and need to be used under the guidance of a professional.
The second is the removal of tooth surface staining through friction. This type of toothpaste mainly removes tooth surface colouring by adding a certain amount of physical friction agents, such as calcium carbonate and hydrated silica, to the product to enhance the friction between the toothpaste and the tooth surface.
Thirdly, the teeth whitening effect is achieved through optical effect. This type of toothpaste using optical complementary colour principle, so that the visual effect of the difference. Such as making the tiny particles of toothpaste attached to the surface of yellow teeth, the use of blue light and yellow light overlap in equal quantities to form a complementary principle of white light, so that people have the illusion of whiter teeth. Toothpaste that whitens teeth in this way cannot really remove surface staining.
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