The basic rule: at least every three months
Folktandvården Stockholm explains why: it is the tips of the bristles that do the cleaning. So replace the brush when the bristles start to bend, and after three months at the latest. The American Dental Association says the same, roughly every three to four months, and more often if the bristles are matted or frayed.
Three months is an upper limit. If you brush hard, the brush can be worn out in half that time.
Why a worn toothbrush does a worse job
Splayed bristles don't reach between the teeth and along the gum line as well. According to 1177, the brush is no longer effective at that point. You remove less plaque without noticing, and over time the risk of cavities and gum inflammation goes up. A new toothbrush is one of the cheapest things you can do for your teeth.
Five signs it is time to replace it
- The bristles splay or bend outwards. The most important sign. Hold the brush in front of you: if the head looks even and tidy it is fine, if the bristles point in different directions it is time.
- Three months have passed. Even if the brush looks intact.
- The brush smells bad even though you rinse it. Here are tips on getting rid of a smelly toothbrush.
- You see dark spots on the handle or near the bristles. It may be mould. Read more about mould on a bamboo toothbrush.
- You have been ill. See below.
How often should you replace an electric toothbrush head?
The same rule applies: roughly every three months. Philips says a Sonicare head should be replaced after three months of normal use, meaning brushing twice a day, or when the blue indicator bristles have faded. Some handles also flash when it is time.
If your brush head has no indicator bristles, check the bristles yourself, just like with a manual toothbrush. Writing down the date when you fit a new head helps. If you use Philips Sonicare, our bamboo brush heads with natural bristle come in a 4-pack that lasts one person a year.
Children's toothbrushes
Folktandvården gives the same advice for children: replace the brush when the bristles start to splay, or at least every three months. Children often chew on the brush, so it wears faster and in practice needs replacing more often. More on choosing a brush at every age in our guide to toothbrushes for children.
Should you replace your toothbrush after a cold?
It is common advice from dentists. Bacteria and viruses can stay on the brush for a while. The risk of reinfecting yourself is small, but a new brush costs little and saves you wondering. If someone in the family has a stomach bug and the brushes stand close together in the same cup, replacing them is a good idea.
Does this apply to bamboo toothbrushes too?
Yes. A bamboo toothbrush is replaced by the same rule as a plastic one. Two things are different:
- It needs to dry. The ADA recommends storing the brush upright to air-dry, because a moist brush in a closed container grows more microbes. For bamboo this matters even more, otherwise the handle can start to smell.
- The old brush does not end up as plastic in nature. With natural bristles the whole brush can be composted; only the small copper staple goes to metal recycling. If the brush has nylon bristles, pull them out first.
How many toothbrushes do you need per year?
If you replace every three months, you need at least four toothbrushes per person per year. A family of four needs around 16. It is easier to replace in time if there is always a new one in the drawer. Our 6-pack of bamboo toothbrushes lasts one person about a year and a half.