Do our toothbrushes harbour bacteria?

Toothbrushes. We use them every day and we rarely give them a second thought. But should we be paying closer attention to them? According to several studies, toothbrushes can harbour bacteria that can cause disease.

Back to the past

The first mass-produced toothbrush was produced in 1780 by a man called William Addis. These early toothbrushes used animal bristles instead of the synthetic fibres we use today.

But people slowly became aware that animal bristles weren’t the best choice because they harboured bacteria. A document from 1929 demonstrates the thinking at the time:

“It is becoming well known among authorities on this subject that the use of the ordinary tooth brush does not prevent the spread of disease and germs in the mouth, but rather tends to increase the spreading of the bacteria.”

Modern evidence

Nowadays our toothbrushes are made of synthetic fibres instead of animal bristles. But could our modern toothbrushes still harbour bacteria?

A 2012 study examined the existing evidence into “toothbrush contamination”, which is the theory that brushing spreads bacteria from our mouths to the toothbrush. The researchers looked at the findings of ten studies from 1977 to 2011. All ten studies found that toothbrush contamination is real. In other words, used toothbrushes harbour bacteria. The bacteria aren’t just the harmless type either: some of the bugs they found included E. coli, Staphylococcus aureus and the herpes virus, all of which cause disease.

The studies also found that a toothbrush becomes more contaminated with use. This means the longer you use your toothbrush, the greater the number of bacteria you’ll get.

What can I do about toothbrush contamination?

Thankfully there are a few things you can do to look after your toothbrush. One method is to use mouthwash. You can swill mouthwash around in your mouth before brushing, as this is a proven way to kill most of the bacteria in your mouth and thereby reduce the amount of bacteria transferred to your toothbrush. Another option is to soak your toothbrush in mouthwash before and/or after brushing. This is another proven way to kill most bacteria on a toothbrush.

Also, if you happen to have an ultraviolet light lying around your house, then you’re in luck: one study found that ultraviolet light is effective at decontaminating toothbrushes.

You might think that rinsing your toothbrush under tap water is sufficient, but not so. A study found that toothbrushes rinsed under water still have high levels of contamination.

Of course, another solution is to change your toothbrush often. This way you switch to a new brush whenever your old toothbrush has a lot of contamination.

How often should I change my toothbrush?

Most dentists recommend changing your toothbrush every three to four months. That’s because after three to four months, the bristles on the toothbrush become worn and frayed, which means the toothbrush no longer cleans well.

But in light of the evidence in these studies, it might be a good idea to change your toothbrush more frequently. Or at least you should leave your toothbrush in mouthwash after brushing.