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Ingredients and Functions of Mouthwash Products Varied Select Oral Care Products According to Personal Needs Unsatisfactory Situation for Some Models with Missing Ingredients List or Usage Instructions

  • 2022.12.15

Concerned about bad breath? Some consumers use mouthwash products as part of their oral care routine for killing bacteria and eliminating bad breath. However, as some consumers often have the misconception that the ingredients and functions of mouthwash products on the market are similar, they might only pay attention to the taste, packaging and price when selecting these products. The Consumer Council conducted a survey on 32 models of mouthwash products and discovered that the ingredients, functions and precautions for use varied considerably. Consumers are advised to understand the ingredients and functions of different mouthwash products before choosing a suitable product that addresses their personal needs, such as oral hygiene maintenance, teeth strengthening, halitosis elimination and teeth whitening. Besides, the Council arranged trial use on all the selected mouthwash models. It was revealed that the models were generally only mildly irritating. The Council emphasises that mouthwash products should only be considered as auxiliary products for oral health and consumers should not over-rely on mouthwash for oral cavity cleaning, let alone replacing the good habit of daily teeth-brushing. Consumers should use a toothbrush, interdental brush, and floss, etc. to clean teeth and remove dental plaque every day.

The survey also revealed that more than 30% of the models (10 models) only listed the ingredients in Japanese on the labelling or did not display any related information at all. Furthermore, over half of the models (17 models) did not provide completed user instructions, including a specific recommended usage amount for each use, daily usage frequency and suitable age, or only provided the information in Japanese etc. The situation was not satisfactory as consumers might not be able to fully understand the product features. The Council urges manufacturers or agents to promptly improve their product label for ensuring consumers to fully grasp the user instructions and usage amount, so as to achieve the best dental care results.

The Council purchased 32 mouthwash product models from supermarkets, personal care stores and department stores, etc. Apart from 2 concentrated models which required dilution with water before use, the remaining 30 models could be used directly. The price ranged from $20 to $167 while the total volume ranged from 120ml to 1,080ml. If the cost is calculated according to the usage guidelines, the cost per use was around $0.33 to $6.32, a difference of over 18 times.

Ingredients, Functions and Precautions Vary Amongst Models

Amongst the 32 surveyed models, the labelled ingredients included essential oils, cetylpyridinium chloride (CPC), chlorhexidine, and povidone-iodine (PVP-I), which carry bactericidal functions. Consumers should note that prolonged use of mouthwashes containing CPC or chlorhexidine might stain the teeth and temporarily affect the sense of taste for some individuals. Besides, one model was labelled with PVP-I as the main bactericidal ingredient. As an over-the-counter medicine, PVP-I releases free iodine during its reaction, and therefore such products are not recommended for pregnant women or patients with thyroid disease. Consumers should also be aware that mouthwashes with whitening functions generally contain only a low concentration of hydrogen peroxide (less than 2%) which is much lower than the concentration used by dentists in teeth whitening procedures (about 20-40%). Therefore, the whitening effect for the tooth surface might not be observable within a short period of time. Consumers are advised not to use hydrogen peroxide of high concentration on their own. The Council points out that as different models of mouthwash may contain different ingredients and the usage precautions may also vary, it is essential for consumers to choose a suitable product according to the ingredients and the potential drawbacks.

No Obvious Correlation Between the Alcohol Content and Irritating Sensation Was Found

The Council arranged for 5 adult participants to trial use the 32 models based on the product instructions, then evaluate each model’s level of irritating and mint sensation. The results revealed the irritating level of most models were mild to moderate. After comparing the claimed alcohol content of each model with participants’ opinions regarding irritating level, no significant relationship was observed between the two. In addition, some consumers might believe mouthwash products containing alcohol would have better antiseptic efficacy. However, according to World Health Organization’s guidelines, the alcohol concentration would need to reach 60-80% in order to effectively kill bacteria and viruses, whereas the concentration of alcohol in mouthwash products are generally lower than this level. Therefore, mouthwash products containing alcohol might not necessarily have better bactericidal efficacy.

Do Not Rely Solely on Mouthwash to Prevent Tooth Decay and Bad Breath

Many consumers are troubled by tooth decay and bad breath but the use of mouthwash alone might not be able to cure related oral hygiene issues. A total of 10 survey models were labelled as containing fluoride which could prevent tooth decay. It is worth noting that the fluoride content was generally around 200 parts per million (ppm) in mouthwash products, which is lower than that of toothpaste: 1,350-1,500ppm generally. Therefore, it is not advisable to completely replace toothpaste with mouthwash products for the purpose of fluoride intake. On the other hand, zinc salt in mouthwash products could help reduce the symptoms of bad breath and 5 models claimed to contain various types of zinc salt. Although zinc salt could reduce the production of volatile sulfur compounds (VSCs) by bacteria, consumers should not rely solely on mouthwash to address bad breath and ignore the real causes of halitosis, such as tooth decay and periodontal disease, to prevent delayed medical treatment.

Some Models Were Not Labelled with the Ingredient List or Usage Instructions

As the active ingredients of different mouthwash products might vary, it would be difficult for consumers to understand the product properties and choose an appropriate product if there is no detailed description on the packaging. Out of the 32 models reviewed by the Council, only 22 models were labelled with detailed ingredient information in Chinese or English, 8 models only had Japanese information, and 2 models were found with no ingredient information at all. For the products which may potentially leave stains on the teeth, temporarily affect the sense of taste, or pose health risks on certain individuals, the Council discovered that only 2 models provided reminders to consumers regarding the issue. However, the relevant reminders were only found on the inner page of the label or within the instruction manual inside the package, thus consumers might not have easy access to it when choosing the products. The Council recommends relevant manufacturers to insert comprehensible reminders on the labels to protect consumers’ right in making informed choices.

Detailed instructions for use are equally important for the correct use of the product. Although 27 models included instructions in Chinese or English on the labelling, 2 of them did not provide any recommended usage amount or only recommend using “a small amount” of mouthwash; 7 models did not offer any recommended frequency of use per day; 8 models did not state the suitable age guidelines; and the remaining 5 models only provided instructions in Japanese. The Council stresses that as different models of mouthwash come with different product formulas, their duration of use, usage amount and even the dilution ratio would also differ. If the product does not provide clear instructions for use, consumers might rinse their mouth for too long or too frequently, or use an overly concentrated amount of the product, which might all result in adverse effects on oral health. In addition to the above, 6 models did not indicate the expiry date on the product packaging, which is far from satisfactory.

Always Choose Suitable Mouthwash Products Based on Personal Needs

Despite the fact that mouthwash is a common household oral care product, different family members might have different needs. For instance, young children might not be able to coordinate their mouth and throat muscles well, hence there is a possibility they would accidentally swallow a large amount of mouthwash. The Department of Health (DH) does not recommend the use of mouthwash products for young children under the age of 6. Even if necessary, they should be supervised by an adult when using the product. As for those who have special needs, for example, patients who suffer from severe cavities, dental brace users or individuals who have undergone radiation therapy to the head and neck, fluoride-containing mouthwash can help enhance teeth protection and prevent tooth decay. On the other hand, people at high risk of contracting oral cancer, such as chronic smokers or heavy drinkers, might consider avoiding alcohol-based mouthwash products. Individuals with removable denture should note that distortion, colour fading and rusting might occur if their dentures are soaked in mouthwash for too long. Dentures can be cleaned with a toothbrush and detergent, or soaked in water with dedicated denture cleansing tablets.

The Council had also consulted the DH and Hong Kong Dental Association for their advice on daily oral care. Experts opined that the best and most effective approach for teeth cleaning should be a combination of correctly brushing the teeth together with the use of floss and, where appropriate, interdental brushes, the reason being that dental plaque on the teeth surface can only be removed with a toothbrush and dental floss, whereas mouthwash products cannot penetrate the plaque thoroughly and effectively. As such, mouthwash products should only be considered as an auxiliary product for oral care and should be complemented with good cleaning habits for the ideal outcome.


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