Interdental brushes are small, bristled picks designed to clean the gaps between your teeth where a regular toothbrush can’t reach. They’re simple to use once you know the basics: insert gently at the gumline, move back and forth a few times, and repeat for every gap. European periodontology guidelines give interdental brushes their highest recommendation, rating them above floss as the preferred method for cleaning between teeth.
Why Interdental Brushes Over Floss
If you’ve always assumed floss is the gold standard, the clinical evidence points in a different direction. The European Federation of Periodontology reached unanimous consensus that toothbrushing should be supplemented with interdental brushes when anatomically possible. The same guidelines specifically recommend against flossing as a first choice for patients maintaining their gum health. Studies comparing the two tools find that interdental brushes remove more plaque and lead to greater improvements in gum health than floss, with statistically significant differences in both plaque levels and gum inflammation scores.
The practical reason is straightforward: interdental brushes conform to the shape of the gap and scrub both tooth surfaces at once. Floss works in a single plane. For tight spaces where a brush genuinely won’t fit, floss still has a role. But for most adults, especially those with any gum recession or naturally open gaps, the brush is the more effective tool.
Choosing the Right Size
Interdental brushes come in color-coded sizes, typically ranging from about 0.4 mm to 1.5 mm in diameter. The right size fills the gap snugly without forcing. You’ll likely need more than one size, because the spaces between your front teeth are usually narrower than those between your back teeth.
A brush that slides through with no resistance is too small and won’t clean effectively. A brush you have to push or bend to get through is too large and can damage your gums. The bristles should touch the tooth surfaces on both sides as the brush passes through. If you’re unsure, start with the smallest size and work up. Your dentist or hygienist can also measure your gaps and recommend specific sizes during a checkup.
Step-by-Step Technique
Use your interdental brush once a day, ideally before brushing your teeth so the fluoride from your toothpaste can reach the freshly cleaned surfaces between teeth.
- Hold the brush like a pen. Grip it near the handle with your thumb and index finger. This gives you enough control for the back teeth.
- Insert at the gumline. Gently guide the brush into the space between two teeth, right where the teeth meet the gums. Keep the brush roughly horizontal for lower teeth. For upper teeth, angle slightly downward. Never force the brush into a space. If it starts to bend, you need a smaller size.
- Move back and forth. Push the brush all the way through the gap, then pull it back. Repeat this motion a few times per gap, working the bristles against the gum tissue with some vigor. You’re scrubbing both tooth surfaces and sweeping out food debris and bacterial film at the same time.
- Work through every gap. Move systematically from one side of your mouth to the other so you don’t miss any spaces. Most people have around 12 to 14 gaps to clean between their natural teeth.
- Rinse the brush between gaps. A quick rinse under running water clears the debris from the bristles so you’re not just transferring plaque from one space to the next.
You don’t need toothpaste or gel on the brush. The mechanical action of the bristles does the cleaning. Some people apply a thin layer of toothpaste or an antibacterial gel, but the evidence for added benefit is limited. Dry or with a rinse under the tap is fine.
What to Expect the First Week
Your gums will probably bleed during the first few days. This is normal and actually a sign that those areas need cleaning. The bleeding comes from existing gum inflammation caused by plaque buildup in spaces you haven’t been reaching. For most people, the bleeding stops within a week or two of daily use as the gum tissue heals.
If bleeding persists beyond two weeks of consistent daily use, that’s worth mentioning to your dentist, as it can indicate deeper gum inflammation that needs professional attention. Mild soreness in the gums is also common at first and typically resolves quickly.
Cleaning Around Braces
Braces create dozens of extra surfaces where food and plaque accumulate. An interdental brush is one of the most useful tools for orthodontic patients because it can slide under the archwire and reach areas a regular toothbrush misses entirely.
Start by rinsing your mouth with water to loosen trapped food debris. Then use your regular toothbrush with small circular motions around each bracket, angling toward the gumline. After that, thread an interdental brush under the wire to clean between each pair of teeth. The technique is the same gentle back-and-forth motion, just with the added step of navigating under the wire first. A smaller brush size usually works best here since the wire limits access. For the area directly around each bracket, a small round-headed toothbrush can help you get the angles right.
Cleaning Around Implants and Bridges
Implants need the same daily cleaning as natural teeth, and interdental brushes are particularly well suited for them. The space around an implant post often has a slightly different shape than a natural tooth root, and a brush conforms to that shape better than floss does. Use the same gentle insertion and back-and-forth technique, being careful not to scratch the implant surface with an exposed wire core. Some brushes are specifically designed with a plastic-coated wire for use around implants.
For bridges, the brush can reach under the false tooth (the pontic) where food collects against the gum. Slide the brush into the space from the side and clean with the same back-and-forth motion.
When to Replace Your Brush
With daily use, a single interdental brush lasts about one to two weeks. Replace it when the bristles become visibly frayed or bent, or when the wire core shows any signs of damage like kinking or bending. A worn brush cleans poorly and a damaged wire can irritate your gums. After each use, rinse the brush thoroughly and let it air dry. There’s no need to sterilize it, but storing it upright or in a ventilated cap helps the bristles dry between uses and last a bit longer.
Common Mistakes to Avoid
The most frequent error is using one size for your entire mouth. Your gaps vary, and a single brush size will be too loose in some spaces and too tight in others. Keep two or three sizes on hand.
Forcing the brush is the second big mistake. If a brush won’t slide in smoothly, switch to a smaller size or try floss for that particular gap. Forcing bends the wire, damages the bristles, and can injure your gum tissue. For very tight contacts, especially between front teeth in younger adults, an interdental brush may simply not fit, and that’s where floss or a thin interdental pick is the better option.
Skipping the back teeth is also common because they’re harder to reach. Angling the brush slightly and using a mirror can help. The gaps between molars tend to be larger and accumulate more plaque, so they’re arguably the most important ones to clean.