If you throw your toothbrush in the trash every time you get sick, it may be unnecessary: Toothbrushes you use while you have strep or a sore throat don’t continue to harbor the germs you had while sick, according to a new study presented at the Pediatric Academic Societies in Washington, D.C., last week.
Researchers from the University of Texas Medical Branch at Galveston tested toothbrushes to see whether A streptococcus, the bacteria that causes strep, was present. Of the 54 brushes examined, 14 had been used by participants with strep throat, 13 had been used by participants with a sore throat (but not strep), and 27 were used by healthy participants. The bacteria was detected on just one of the toothbrushes—and it had been used by a healthy participant.
While these findings suggest it’s probably safe to keep your toothbrush even if you’ve used it while sick, there are other times when it’s best to say buh-bye to your brush. The main one: If it’s been three months since your last switch, it’s time to grab a new brush, says Carolyn Taggart-Burns, DDS, fellow in the Academy of General Dentistry. Here, she shares a few other instances in which you really need to trash yours:
The bristles are worn
Any time they’ve lost their rigidity or their color, it’s a good indication that you’re due for a new brush. Another thing to keep in mind: If you have toothpaste buildup, it’ll harbor tons of bacteria, says Taggart-Burns. So consider that another sign it’s time for a replacement.
You’ve dropped it…anywhere
Not that the two-second rule applies in general, but it really doesn’t apply to toothbrushes. “We brush our teeth in one of the dirtiest rooms in our house,” says Taggart-Burns. Your toothbrush can pick up bacteria even if you’ve just dropped it in the sink for a few seconds. As a general rule of thumb, if your toothbrush ends up anywhere it’s not supposed to be, just toss it.
You bumped toothbrushes with your roommate
The second your toothbrush touches someone else’s (or—gross—they use it), you’re basically swapping hosts of different bacteria with that person, says Taggart-Burns. Whether this might make you sick really depends on the person in question and how close you are. For example, you and your significant other are sharing the same bacteria to begin with, so using his brush (or vice versa) probably won’t expose you to any foreign bacteria that might make you ill. If, however, your brush touches anyone else’s, you’d better hit the store for a new one.
You’ve been traveling
If your toothbrush has been in a closed container for more than a day, you should probably throw it out. Since bacteria will grow in any moist environment, it’s important to let your brush dry as fully and as quickly as possible between uses to cut back on grimy germ growth.
To keep your toothbrush as bacteria-free as possible while you travel, look for a container that has holes for ventilation and let it air out as soon as you reach your destination. You can also keep your case clean by throwing it in the dishwasher after each use; the heat will knock out any bacterial growth.
More from WH:
8 Ways to Beat Bad Breath
How Clean Teeth Keep You Healthy
The Cure for Sensitive Teeth