Interdental brushes vs floss: how to choose
Interdental brushes and floss both clean between teeth, but they work best in different spaces. Learn which tool fits your mouth and how to use each one.
Medically reviewed by Dr. Jose, DDS — September 14, 2026
Why clean between your teeth?
Brush bristles can’t reach the surfaces between teeth where food and plaque build up. Cleaning these spaces every day helps prevent cavities and gum disease. You have two main tools to choose from: floss and interdental brushes.
What floss does
Floss is a thin string that slides between teeth to remove plaque and food debris. It works best in tight spaces where teeth sit close together. Traditional floss requires some technique — you guide it gently between teeth, curve it around each tooth, and move it up and down below the gum line.
Floss reaches the spaces where an interdental brush cannot fit. If your teeth are snug against each other, floss is often your most effective option.
What interdental brushes do
Interdental brushes are tiny bottle-brush-shaped tools with bristles arranged around a center wire or plastic core. They’re designed to clean the larger gaps between teeth — especially spaces that open up as you move toward your back molars, and gaps created by gum recession or tooth loss.
These brushes work by inserting the bristled end gently between teeth and using a short, gentle back-and-forth or rotary motion. They remove plaque and debris without requiring the threading motion that floss demands.
How to choose
Use floss if:
- Your teeth sit very close together with minimal gaps
- You have a smaller mouth or prefer a traditional approach
- Your dentist or hygienist recommends it for your specific spaces
Use interdental brushes if:
- You have visible gaps between your teeth
- Floss is difficult for you to manipulate (due to hand dexterity, arthritis, or other concerns)
- You have gum recession that creates larger spaces
- You wear certain types of dental work, like bridges or implants, where a brush may fit more easily
Many people benefit from using both tools — floss for tight spaces and interdental brushes for larger gaps.
Getting the right fit
Interdental brush sizes range from extra-small to large. Using the wrong size defeats the purpose: too small and you miss plaque; too large and you risk discomfort or gum irritation.
Your dentist or hygienist can demonstrate the correct size for each gap in your mouth during a visit. They can also show you the proper technique so you clean effectively without damaging your gums. Ask them to watch you use the tool to confirm your method.
Tips for success
- Be gentle. Whether using floss or a brush, never force the tool between teeth or below the gum line. If you meet resistance, stop and ask your dentist for guidance.
- Go daily. Clean between your teeth every day, just as you brush. Morning or evening — consistency matters more than timing.
- Replace worn brushes. Bent or frayed bristles don’t clean well and may scratch gums. Replace your interdental brush when it shows wear.
- Store brushes properly. Let them air-dry after use and store in a clean, dry place.
How MediMouth helps
Choosing the right interdental cleaning tool is personal to your mouth’s shape and spacing. A MediMouth dental provider can examine your teeth and gaps during an exam or cleaning, recommend the best tool for you, and show you how to use it correctly. If you’re unsure whether floss or an interdental brush (or both) is right for you, schedule a visit to get personalized guidance. See our Brushing and Flossing Guide for a complete daily routine.
Frequently asked questions
Can I use interdental brushes and floss together?
Yes. Many people use both — floss for tight spaces between teeth and interdental brushes for larger gaps where a brush fits more easily. Your dentist or hygienist can recommend which combination works best for your mouth.
How do I know what size interdental brush to use?
Interdental brushes come in multiple sizes. Your dentist or hygienist can show you the right size for each gap in your mouth — it should fit snugly without forcing. They may recommend different sizes for different areas.
Do I need to replace interdental brushes?
Yes. Replace the brush when bristles become bent, frayed, or worn. This usually happens after several weeks of regular use. A worn brush cleans poorly and may irritate your gums.