What are toothbrush bristles made of?
Toothbrush bristles are normally made from plastic.
There are a couple of plastic free alternatives for toothbrush bristles but those that are available (animal hair and plant fibres) are not necessarily good options for your dental health.
There is a lack of evidence to support the eco claims some companies make about their toothbrush bristles.
Whilst claims are sometimes made in good faith, it is important to note that the only way you can really decide whether something has a lower impact on the environment is by doing a life cycle assessment following strict international criteria (ISO 14040/44).
Here are Electric Teeth, we are not sustainability or plastics experts, but we are doing our best to thoroughly research and create a guide on how to make your dental health more eco-friendly.
Hopefully we can help you make decisions that will lessen your impact on the environment.
Plastic toothbrush bristles
The new plastic can be made from traditional fossil fuel based resources. The alternative is using renewable resources to make bio-based plastic.
Regardless of the starting ingredients, the end product is still plastic.
Nylon toothbrush bristles are the most common. In fact, the first use of nylon was as toothbrush bristles in the 1930s!
Nylon, sometimes also referred to as polyamide or PA, is a very versatile material. There are many different types of nylon, and different ways to make it too. It is identified by Plastic Resin Code 7 (Other Plastics).
The benefits of nylon include that it is a strong and flexible material, and is able to withstand a lot of friction. It is easily rinsed and dried, so is a hygienic material — perfect for something you are putting in your mouth!
The types of nylon used in toothbrush bristles is:
- Nylon 6 – Poly(caprolactam), e.g. DuPont™ Tynex® (nylon 612)
- Nylon 4 – considered to be “biodegradable“.
When researching this post found some references to nylon-4 toothbrush bristles, and some toothbrushes claiming to have them (which on further research was not accurate).
Some other blogs have discovered this too. In many hours of searching, I could not find any manufacturers of nylon-4 bristles for toothbrushes and so I am not sure they exist.
There is a lack of information about toothbrush bristle manufacturers online. I spent hours searching for information and it doesn’t seem to be available.
I would end up in a cycle of reading other eco dental product content, none of which was referenced. I’ll be honest — it’s a bit of a void for information.
Many environmentally friendly toothbrush producers still opt for nylon bristles because there is not a feasible alternative.
Bio-based toothbrush bristles
Bio-based bristles are just one type of bioplastic which can be used to make toothbrushes. Bioplastics is a term used to mean many different things – it can include:
- bio-based plastics: plastics which are derived from natural/plant-based resources instead of fossil fuels. The end structure is the same, it is just a different starting block. This is not an indicator of biodegradability.
- biodegradable plastics : either fossil fuel derived plastics or bio-based plastics, and which are able to biodegrade. This means they break down with the aid of microorganisms. The broken down material may include water, smaller bits of plastics or toxic residues.
- compostable plastics : either fossil fuel derived plastics or bio-based plastics, but which are compostable. This means they break down, under specific conditions, into biomass, carbon dioxide and water. The biomass remaining after composting is beneficial to the earth.
Toothbrushes which call themselves bioplastic seem to refer to the use bio-based plastics. In other words, the main difference is that renewable resources can also be used to make plastics. Examples include:
- Castor bean oil to make nylon
- Corn based PLA
Advantages of bio-based plastics include:
- Reducing the use of fossil fuels
- Smaller carbon footprint
- (Potentially) faster decomposition, although there are many variables involved in this.
Bite does a really good job of explaining why bio-based plastic bristles can be a good alternative.
Brush With Bamboo also clearly explains what bio-based means when it comes to bristles.
TIO are in the process of completing life cycle analysis, but state that bio-based nylon bristles have a carbon footprint value of 4.0 kg CO2/kg compared to > 9 CO2/kg for conventional nylon bristles.
But they are guilty of something I find particularly frustrating. Like some other companies, they try to drop the word plastic in an attempt to appear to be more environmentally friendly. This is misleading because regardless of the source of the basic ingredients (oil or plant), it is still plastic!
I am also concerned by the number of companies who are misleading customers about their toothbrush bristles. I want to be absolutely clear, bristles made from castor oil etc are still plastic. I’ve seen examples of brushes being sold as:
- 100% plant based
- 100% biobased
- Plastic free
- Biobased instead of plastic based
Bio-based bristles are still plastic. They still behave the same as traditional plastic, and they still have the same issues with disposal.
It is possible that some bio-based plastics can also be biodegradable. Read on to find out more about biodegradable plastics!
Examples of brushes we have tested which use bio-based plastic toothbrush bristles include:
- Bite bamboo brush
- Brush With Bamboo
- Etee Bamboo Brush with replaceable head
- Radius Tour Travel toothbrush
- Radius Big Brush toothbrush
- Radius Source Toothbrush
I cover some of these in more detail in my article on the most eco-friendly toothbrushes.
Natural bristle materials
Natural bristle materials are those that are taken from natural sources such as plants and animals, and which are largely unchanged before being used as toothbrush bristles.
They don’t undergo any major chemical changes, and are not used to make another material which then makes bristles. The bristle material is just cleaned and trimmed to size.
The most common natural bristle material is boar hair. This was traditionally used hundreds of years ago for toothbrushes and hairbrushes prior to the discovery of nylon.
One downside is that it is an animal product and is therefore unsuitable for people who want to avoid animal products.
Animal hair toothbrush bristles can also harbour more bacteria than nylon due to the natural structure containing a hollow canal. Processing boar hair is also very difficult, and it is not always possible to get a rounded tip which will not damage the gums during brushing (Fattal et al).
Plant fibres are an alternative to animal hair for a natural bristle.
Sisal is a fibre derived from the agave plant. It is a fiber produced in nature. It is considered too hard for toothbrushes, and does not flex very well. Sisal fibres would need replacing every few uses, which is very resource intensive.
Jute fibres, which also come from plants, have also been suggested as a natural toothbrush bristle. These are soft and flexible. They do not stand up to the pressures of toothbrushing and would need replacing so often they would increase waste.
Chewing sticks are an alternative dental hygiene product. They are made from roots or branches of trees, most commonly Salvadora Persica.
Names for these sticks include:
- ‘miswak’ in Arabic
- ‘koyoji’ in Japanese
- ‘qesam’ in Hebrew
- ‘qisa’ in Aramaic
- ‘mastic’ in latin.
Chewing sticks have been used as a form of dental cleaning for thousands of years. A review of available evidence found they have a positive effect on the gums, and are able to remove dental plaque, whilst other studies have also found them to be as effective as toothbrushes for people with small amounts of plaque.
Disadvantages of using chewing sticks include more teeth having gum recession, and that this recession is worse than for people who use a toothbrush. The World Health Organisation states:
“Communities can be encouraged to continue the use of miswak and other chewing sticks wherever they are widely available for tooth brushing in combination with the use of fluoride toothpaste.”
There are not many examples of brushes made using natural bristles materials. The brushes below we have tested but may not necessarily be available in your area:
- SWAK toothbrush – made from miswak.
- Yaweco Interchangeable Brush Head Toothbrush – made from boar hair.
What about charcoal-infused bristles?
“Charcoal” toothbrush bristles are normally made from nylon or polyester bristles infused with charcoal.
The bristles are not more natural and still contain plastic. The plastic used for the bristles can be made conventionally from fossil fuel based ingredients, or can be made from bio-based plastic.
One example is DuPont’s Herox® Binchotan filaments which contain a minimum of 65% bio-based plastic filament, embedded with charcoal.
The charcoal is often called binchotan charcoal, which originates in Japan and is believed to have “purifying” benefits.
Charcoal infused toothbrush bristles are associated with many different claims of benefits for your dental health, from improving bad breath to tooth whitening. We go into these claims in our article about charcoal bristle toothbrushes.
Companies using it claim the charcoal has natural antimicrobial activities. There is actually not much clinical evidence to prove these claims.
A small study which compared toothbrushes used in real life did find that the charcoal infused bristles had lower levels of bacteria. Two other studies, by Kaur et al and Lee et al, showed charcoal containing toothbrushes attract fewer bacteria when compared to normal toothbrushes.
But other studies advise that there is no difference in the bacteria count between charcoal infused toothbrushes and regular nylon bristles in a lab setting.
Whilst lack of high quality evidence does not mean the claims aren’t true, it does mean they aren’t proven yet.
If charcoal infused brushes were to reduce the amounts of certain types of bacteria in the mouth, they could in theory improve bad breath. However there is no evidence to actually prove this at the current time.
There is no evidence to support charcoal based bristles as being more environmentally friendly.
In fact, additional ingredients (charcoal) are used in the manufacturing process with no massive increase in effectiveness. I would say these are less environmentally friendly than other alternatives.
Examples of products we have tested with charcoal infused bristles:
- Burst Sonic toothbrush
- Colgate Bamboo brush
- Organically Epic Bamboo Brush
Can toothbrush bristles be recycled?
In theory, yes toothbrush bristles can be recycled. In practice, it is not easy to recycle toothbrush bristles.
As discussed above, toothbrush bristles are normally made from nylon.
Nylon is a thermoplastic material which melts when it is heated up.
The good thing about nylon is that it can be melted, cooled and then melted again without losing the quality of the plastic.
But because nylon’s melting temperature is relatively low it can be difficult to confirm that the recycled nylon is free from contaminants.
This is why nylon needs to be thoroughly cleaned before the recycling process.
It also means that recycled nylon is unsuitable for making new toothbrush bristles, which come into contact with the mouth.
The post-consumer recycled nylon can be used for other purposes though. This diverts the used nylon bristles from landfill, and the recycled nylon lessens the need for new raw materials for the new product.
Recycling nylon is not as easy as recycling other common plastics, such as those used in plastic packaging for food.
In Canada, toothbrush bristles (nylon or other plastics) are not normally accepted in curbside recycling.
Toothbrushes need to be sent to specialist recovery programmes.
We have an article that discusses all the methods for recycling your manual toothbrush, including TerraCycle’s specialist systems and take back schemes from manufacturers.
For “natural” fibres such as animal hair or plant fibres, you could compost these at home or with garden waste. However unless they have been independently tested, don’t automatically assume they will fully decompose.
Composting websites seem to agree that animal hair is good to compost though.
Be cautious about putting “biodegradable plastic” on your home compost pile, unless it has been tested by an independent group and confirmed safe to do so.
This article really explains the problems with so-called “bioplastics” in a lot of good detail. Also read on to find out more.
Are toothbrush bristles biodegradable?
Some toothbrushes claim to be 100% biodegradable.
From the research I have done, I believe this is misleading.
Biodegradable would make you think that it can be thrown on a compost pile with no problems. But that isn’t the case.
Biodegradable generally is a misleading term. It is vague and doesn’t mean that the material will break down fully and leave no residues. And when it comes to plastics, it is possible for microplastics to be left behind.
Even if materials have the ability to biodegrade, it isn’t a guarantee that they will do so.
For example, if they end up in an oxygen deprived (anaerobic) landfill, or cold water, they will not break down.
Biodegradable plastics are also not recyclable with other plastic recycling streams and can contaminate them so that the recycled plastic is not usable.
‘Compostable’ is what you are probably thinking of when considering an environmentally friendly alternative. As a label, it is normally protected from false advertising, and there are strict independent testing criteria to be met for these labels to be awarded.
Biodegradable claims are not supported with any independent testing, because there isn’t any. If you want to put something on a compost pile (home or industrial), the product needs to be tested to meet these standards.
Most toothbrushes are not tested. In fact, I haven’t come across any that have been tested. I suspect this is because they know they cannot meet the strict criteria to claim to be compostable.
Toothbrushes are not compostable
So could a toothbrush be compostable? Not at the moment:
- There are no bristles of good enough quality for brushing teeth but which are also compostable.
- Bristles are held in place by staples, which are not compostable.
- So-called biodegradable plastics have some evidence to support the fact that they will break down within a couple of years in some environments, but this isn’t effective enough to be labelled compostable.
- Bamboo handles can be compostable, but the problem really does lie with the toothbrush bristles.
Is nylon biodegradable?
Nylon 6 is the most commonly used material for toothbrush bristles and this is not biodegradable or compostable.
There is some evidence that nylon 4 does degrade in soil, but it is not well researched.
Tokiwa et al studied the biodegradability of plastics and produced a paper summarising their findings.
Nylon 4 has been shown to be broken down by microorganisms in specific environments. It is biodegradable. In controlled tests, it was broken down as quickly as 4 months so, in theory, it is compostable.
However, the authors of the paper do again state that the ability of a plastic to be broken down depends on both its physical and chemical properties. Because of this, it is important that individual products be tested independently.
There aren’t any studies about nylon 4 toothbrush bristles so be cautious when manufacturers advertize their bristles as biodegradable. I also can’t find information on manufacturers of nylon 4 toothbrush bristles, nor toothbrushes that use them.
Don’t be fooled by the label biodegradable. Something biodegradable is simply breaking down into smaller pieces. In theory, almost all materials are biodegradable. It’s just that some things can take a very long term (hundreds, or even thousands of years). We also do not know what the end products are or that it doesn’t leave microplastics behind when it degrades.
The term biodegradable is often used by manufacturers who don’t have independent testing to support their claims.
Some companies say that bio-based plastics are able to break down more quickly than traditional plastics. These are plastics where a renewable source is used to make the plastic instead of traditional fossil fuels.
There is no evidence to support this where the final plastic structure is the same as for a fossil fuel based plastic.
The British Plastic Federation explains the ability of a plastic to break down has nothing to do with the source material. It is to do with the structure of the plastic that is made.
Biodegradability depends upon the size and shape of the plastic, any treatments it has had.
By contrast, compostable materials break down into biomass, carbon dioxide and water, with the biomass being beneficial to the soil. A compostable label needs to be independently assessed (see our eco definitions page for more info).
The only way to be sure that the toothbrush bristles are compostable is for them to be tested independently. In reality, there isn’t a toothbrush available that has achieved this.
How do bristles affect teeth brushing?
Yes, the shape, arrangement and material of toothbrush bristles can affect your cleaning.
Toothbrush bristles are the part of the toothbrush which comes into contact with the teeth. They help to physically remove plaque and food debris.
Bristles come in different strengths – soft, medium and hard. But these are actually tested scientifically too. The evidence shows very little difference in the plaque removing ability of different firmness of bristles.
Bristles are trimmed at the end to have different end shapes. This is easier to achieve in some materials, like nylon, than it is in others, like animal hair. This end shape is important because sharp ends have the potential to cause damage to the gums. Needle shapes bristles also wear more quickly, affecting their ability to clean properly.
The effectiveness of cleaning can be influenced by how the bristles are arranged. Toothbrushes with either multi-level bristles or angled bristles perform better than the conventional flat-trimmed bristles.
We have taken this into account for our recommendations for the best manual toothbrush.
It is also important to regularly change your toothbrush because of wear of the toothbrush bristles. Studies have shown that worn bristles are less effective at cleaning, especially between the teeth.
Toothbrushes require testing before being sold in many countries. These tests follow strict guidelines.
One of these is a bristle abrasiveness test (ISO 20126 and ISO 20127). Bristles that are too firm are not permitted because they have the potential to cause wear on the tooth surface (abrasion), and can also traumatize the gum.
Long term use of bristles that are too hard can injure the gum (Zanatta et al). This damage can also be caused by bristles with sharp or jagged edges.
Other factors that affect the gums are the diameter of the bristles and the design of the brush head.
The hardness of the bristles may also cause tooth wear, although the different studies available show a lack of conclusive evidence.
According to Bizhang et al, in laboratory conditions soft toothbrush bristles (diameter 0.18mm) caused more tooth wear than medium (0.2mm) or hard (0.23mm) bristles. They believe this is because the more flexible soft bristles have a greater surface contact and transfer the abrasiveness of the toothpaste.
Other research, such as that by Cifcibasi et al say that bristle design and hardness has very little effect on tooth wear.
For daily use, it is recommended the bristles have a rounded edge (Voelker et al), have a wider diameter, and are of medium hardness (specifically not soft!)
As a dentist, my recommendation for most people is medium bristles. Use soft bristles if you have sore gums. I generally don’t recommend hard bristles due to the potential for damage to the gums and long term can cause tooth wear.
Ultimately, whether you choose soft, medium or hard bristles is a personal choice. So long as the correct brushing technique is used, there is no noticeable effect on your cleaning ability.
What about brushes like Radius that have more bristles?
Some brushes advertise that they have more bristles than an average toothbrush.
One example is Radius, which says:
RADIUS toothbrushes have 300% more bristles than your average toothbrush, which means that our brushes last, on average, 6-9 months instead of the typical 3 months. This means our toothbrushes are thrown out less often.
There is little evidence to support this one way or the other. It may be possible that the brushes wear less quickly than on an average toothbrush. But the rate of wear also depends on bristle material and how they are cut, as well as arrangement.
Whilst the toothbrush bristles may remain intact and so safe to use (again though, there is no evidence published to prove this), it is still recommended to change your toothbrush every three months.
That is because of the amount of bacteria that grows on a toothbrush.
A study in Korea investigated levels of different types of bacteria found on toothbrushes. The authors found that after three months the bacterial levels more than doubled compared to a toothbrush which had been used for one month. Some studies actually argue for replacing your toothbrush every 1-2 months because of this.