How to Use an Interdental Brush Correctly

Introduction

One of the most common questions patients ask their dental team is whether brushing alone is truly enough to keep teeth and gums healthy. Many people sense that their toothbrush isn't reaching every surface — and they're right. Standard toothbrushing, even when performed well, cleans only around 60% of tooth surfaces, leaving the spaces between teeth vulnerable to plaque build-up.

This is why so many people search online for guidance on how to use an interdental brush correctly. These small, specially designed brushes are one of the most effective tools for cleaning between teeth, yet many patients are unsure about the proper technique, the right size to choose, or how often they should be used.

In this article, we'll explain what interdental brushes are, how they work, the correct technique for using them, and how they fit into a thorough daily oral hygiene routine. Understanding how to clean between your teeth properly matters because plaque that accumulates in interdental spaces is a leading contributor to gum disease and tooth decay. If you have any concerns about your gum health or are unsure which cleaning aids are most suitable for you, a professional dental assessment can provide personalised recommendations.

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What Is an Interdental Brush?

An interdental brush is a small brush specifically designed to clean the spaces between your teeth — areas that a regular toothbrush cannot easily reach. It consists of a small handle attached to a thin wire core surrounded by soft bristles. These brushes come in a range of sizes, from very fine (suitable for tight gaps) to larger sizes for wider interdental spaces.

Unlike dental floss, which uses a thin thread to slide between teeth, interdental brushes physically sweep plaque and food debris from the surfaces on either side of the gap. Research published in dental journals, including studies referenced by the British Society of Periodontology, has consistently shown that interdental brushes are highly effective at reducing plaque and the early signs of gum inflammation when used as part of a daily routine.

Interdental brushes are widely recommended by dental professionals across the UK. Your dentist or dental hygienist can advise you on the correct sizes for different areas of your mouth, as most people need more than one size to clean all their interdental spaces effectively.

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Why Cleaning Between Your Teeth Matters

The Science Behind Plaque and Gum Disease

To understand why interdental cleaning is so important, it helps to know a little about how plaque affects your oral health. Plaque is a soft, sticky film of bacteria that forms continuously on every surface of your teeth. When plaque accumulates in the spaces between teeth and along the gumline, the bacteria produce acids and toxins that irritate the gum tissue.

In the early stages, this irritation leads to gingivitis — a mild form of gum disease characterised by redness, swelling, and occasional bleeding when brushing. Gingivitis is generally reversible with improved oral hygiene. However, if plaque is not regularly removed from interdental spaces, the condition may progress to periodontitis, a more advanced form of gum disease that affects the supporting bone and tissues around the teeth. Periodontitis, if left unmanaged, can eventually lead to tooth mobility and tooth loss.

The interdental areas are particularly vulnerable because they create sheltered environments where bacteria thrive undisturbed. By using an interdental brush to disrupt and remove plaque from these spaces daily, you can significantly reduce the risk of both gum disease and interdental decay. If you're experiencing any signs of gum disease, such as persistent bleeding or swelling, your dental team at South Kensington Dental can carry out a thorough assessment.

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How to Use an Interdental Brush Correctly

Using an interdental brush properly ensures you get the maximum benefit without causing any damage to your gums or teeth. Here is a step-by-step guide:

Step 1: Choose the Right Size

Interdental brushes come in colour-coded sizes. The brush should fit snugly into the space between your teeth — you should feel gentle resistance from the bristles against the tooth surfaces on either side. If the brush slides through without touching the sides, it's too small. If you have to force it, it's too large. Most people need two or three different sizes to accommodate the varying gaps throughout their mouth.

Step 2: Insert Gently

Hold the brush between your thumb and forefinger. Gently guide it into the interdental space, angling slightly to follow the natural line of the gap. Do not force the brush. For front teeth, insert the brush straight through. For back teeth, it may help to curve the wire slightly or approach from the inside (lingual side) of the mouth.

Step 3: Use a Simple Back-and-Forth Motion

Once the brush is in the space, move it gently back and forth once or twice. This motion sweeps plaque from the surfaces on both sides of the gap. There is no need to spin or twist the brush — a simple horizontal movement is sufficient.

Step 4: Clean Every Space

Work systematically around your mouth, cleaning every interdental space. Rinse the brush under water as you go to remove debris from the bristles.

Step 5: Rinse and Replace

After use, rinse the brush thoroughly and allow it to air dry. Replace your interdental brushes when the bristles become worn or bent — typically every few days to a week, depending on use.

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Choosing the Correct Interdental Brush Size

Selecting the appropriate size is one of the most important aspects of effective interdental cleaning. Using a brush that is too small will not adequately remove plaque, whilst using one that is too large may cause discomfort or gum trauma.

Most interdental brush brands follow a standardised colour-coding system (ISO sizes), ranging from pink (the smallest, approximately 0.4 mm) through to black (the largest, approximately 1.5 mm). Your dental hygienist can measure your interdental spaces during a routine hygiene appointment and recommend the exact sizes you need.

It is perfectly normal — and very common — to use different sizes for different areas of your mouth. The spaces between front teeth are often narrower than those between back teeth. Getting the right fit for each gap ensures thorough plaque removal and a comfortable experience.

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Common Mistakes to Avoid

Even with the best intentions, patients sometimes develop habits that reduce the effectiveness of interdental brushing or cause unnecessary discomfort. Here are some common mistakes to be aware of:

• Forcing the brush into tight spaces. If a brush doesn't fit comfortably, try a smaller size rather than pushing it through. Forcing can damage the gum tissue between teeth.
• Using the wrong size. A brush that is too small won't clean effectively. If you notice no resistance at all when the brush passes through, you likely need a larger size.
• Skipping areas. It can be tempting to avoid the back teeth, but these areas are often the most prone to plaque accumulation and decay.
• Not replacing brushes regularly. Worn bristles and bent wires cannot clean properly and may irritate your gums.
• Only using interdental brushes when food is stuck. Interdental brushes are most beneficial as a daily preventative tool, not just for removing visible food debris.

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Interdental Brushes vs Dental Floss

Patients often wonder whether they should use interdental brushes, dental floss, or both. While both tools aim to clean between teeth, they work differently and may suit different situations.

Interdental brushes are generally considered more effective at removing plaque from interdental spaces, particularly where there is sufficient room for the brush to fit. They are also easier for many people to use, which often leads to better consistency in daily cleaning routines.

Dental floss may be more suitable for very tight contacts where even the smallest interdental brush cannot pass through comfortably. Some patients benefit from using a combination of both tools.

Your dental team can advise which approach is most appropriate for your individual needs. The most important thing is that you clean between your teeth every day using whichever method works best for you.

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When Professional Dental Assessment May Be Needed

While interdental brushing is an important part of your home care routine, there are situations where professional guidance is advisable:

• Bleeding that persists after two weeks of regular interdental brushing. Some initial bleeding when you first start using interdental brushes is normal and usually settles within a week or two as gum health improves. However, if bleeding continues, it may indicate underlying gum inflammation that needs professional attention.
• Pain or discomfort when inserting the brush, which could suggest gum recession, tooth decay, or an ill-fitting restoration in that area.
• Swelling, tenderness, or redness of the gums that does not improve with good oral hygiene.
• Difficulty finding the right brush size or uncertainty about technique. A dental hygienist can demonstrate the correct method during your appointment.
• Loose teeth or receding gums, which may be signs of advancing periodontal disease requiring clinical management.

If you notice any of these signs, arranging an appointment for a dental examination allows your dental team to assess your oral health thoroughly and recommend any appropriate care.

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Prevention and Oral Health Advice

Incorporating interdental brushing into your daily routine is one of the most effective steps you can take to maintain good oral health. Here are some practical tips:

• Clean between your teeth once a day, ideally in the evening before brushing your teeth. This loosens plaque and debris so that your toothpaste's fluoride can reach more surfaces.
• Brush your teeth twice daily with a fluoride toothpaste for two minutes each time.
• Attend regular dental check-ups and hygiene appointments so that any early signs of gum disease or decay can be identified and managed promptly.
• Limit sugary snacks and acidic drinks between meals to reduce the risk of tooth decay.
• Don't rinse with water immediately after brushing — spit out excess toothpaste but allow the fluoride to remain on your teeth for continued protection.
• Ask your dental team for a demonstration if you are unsure about your technique. A few minutes of hands-on guidance can make a significant difference to the effectiveness of your home care.

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Featured Snippet

How do you use an interdental brush correctly?

To use an interdental brush correctly, choose the right size for each gap, gently insert the brush between your teeth without forcing, and move it back and forth once or twice to remove plaque. Clean every interdental space once daily. Replace the brush when bristles become worn. If unsure about sizing or technique, ask your dental hygienist for personalised guidance.

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Key Points to Remember

• Interdental brushes clean the 40% of tooth surfaces that a regular toothbrush cannot reach.
• Choose the correct brush size for each gap — most people need more than one size.
• Use a gentle back-and-forth motion; never force the brush into a space.
• Clean between your teeth once a day as part of your regular oral hygiene routine.
• Some initial gum bleeding is normal but should settle within one to two weeks.
• If bleeding, pain, or swelling persists, seek a professional dental assessment.

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Frequently Asked Questions

How often should I use an interdental brush?

Interdental brushes should ideally be used once a day. Many dental professionals recommend using them in the evening before brushing your teeth, as this allows fluoride toothpaste to reach the cleaned interdental surfaces more effectively. Consistent daily use is more beneficial than occasional thorough cleaning. Over time, daily interdental brushing becomes a quick and simple addition to your routine — typically taking only one to two minutes for the entire mouth.

Is it normal for my gums to bleed when I first use interdental brushes?

It is quite common to experience some bleeding when you first begin using interdental brushes, particularly if plaque has been building up in those spaces. This bleeding is usually a sign of existing gum inflammation (gingivitis) and typically settles within one to two weeks of regular use as the gum tissue becomes healthier. However, if bleeding continues beyond this period or is heavy, it is sensible to arrange a dental appointment so that your gum health can be assessed professionally.

Can interdental brushes damage my teeth or gums?

When used correctly and in the appropriate size, interdental brushes are safe and should not damage your teeth or gums. Problems may arise if you force a brush that is too large into a tight space, or if you use excessive pressure. The wire core of an interdental brush is coated to protect tooth surfaces, but choosing the right size and using a gentle technique is important. Your dental hygienist can help ensure you are using the brushes safely and effectively.

What size interdental brush should I use?

Most people need two or three different sizes to clean all the spaces in their mouth. The brush should fit snugly, with the bristles touching both sides of the gap. If the brush passes through without resistance, it is too small; if it cannot enter the space without being forced, it is too large. Your dental team can measure your interdental spaces and recommend the appropriate sizes during a hygiene appointment, which takes the guesswork out of the process.

Can I reuse an interdental brush?

Yes, interdental brushes are designed to be used multiple times. After each use, rinse the brush under running water to remove any debris, and allow it to air dry. Replace the brush when you notice that the bristles have become splayed, flattened, or the wire has bent — this usually happens after three to seven days of daily use, depending on the brand and how many spaces you are cleaning. A worn brush will not clean effectively and may irritate your gums.

Should I use interdental brushes or floss?

Both interdental brushes and dental floss aim to clean between teeth, but research suggests that interdental brushes may be more effective at removing plaque, particularly in spaces where they fit comfortably. Floss may be preferable for very tight contacts where a brush cannot pass through. Some patients benefit from using both. The most important factor is that you clean between your teeth daily, using whichever method you find most comfortable and are most likely to use consistently. Your dental hygienist can recommend the best option for your individual needs.

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Conclusion

Learning how to use an interdental brush correctly is one of the most valuable steps you can take to protect your oral health. These small but effective tools play a vital role in removing plaque from the spaces between teeth — areas where gum disease and decay most commonly begin. By choosing the right size, using a gentle technique, and cleaning between your teeth every day, you are giving your mouth the best possible care at home.

If you are unsure about your interdental cleaning technique, experience persistent bleeding, or have concerns about your gum health, your dental team can provide tailored advice and guidance during a clinical appointment.

Dental symptoms and treatment options should always be assessed individually during a clinical examination.

For further dental health information and guidance, visit the South Kensington Dental blog.