How often should you replace a toothbrush?

Why the ADA gives a range

Bristles wear with use, and a worn brush is generally considered less effective at cleaning teeth. The ADA's 3 to 4 month guideline is an easy schedule to remember, and many people tie it to the change of seasons. The range is a guide, so how hard you brush and how often will affect when your own brush needs replacing.

The ADA also notes that frayed bristles are a sign to replace the brush early, even if the calendar says you still have time. If you press firmly or chew the bristles, you may see wear sooner than someone with a lighter touch.

Signs it is time

• Bristles that look bent, flattened or spread outward.
• A brush head that looks worn compared with a new one.
• Replacing after an illness is also something the ADA suggests, particularly if the brush was stored near others.
• A child's brush may need replacing more often, since children tend to chew or press harder.

Electric brushes and replacement heads

For an electric toothbrush, the same advice applies to the replacement head, not the handle. Many heads include color-changing indicator bristles, but that feature is the maker's own guide, so follow the ADA interval or the maker's instructions, whichever comes first. Our eco-friendly toothbrush guide covers options with replaceable heads or compostable handles, and the gentle toothbrush guide covers softer bristles.

A dentist or hygienist can tell you whether your brushing style is wearing brushes out unusually fast, and can recommend a bristle firmness that suits your mouth.

Keeping a brush in good shape between replacements

Rinse the brush thoroughly after use and let it air dry in an upright position, and avoid sharing it. The ADA also advises against covering a wet brush in a closed container, since moisture can linger. None of this replaces the replacement schedule, but it helps you get a clear picture of the brush's condition when you inspect it.

Sources

• American Dental Association (ADA)
• ADA MouthHealthy consumer guidance