Last updated: May 2026. This guide covers how to floss properly, how to choose and use interdental brushes, and which method is best for your teeth. All information is sourced from the NHS, the UK Government's Delivering Better Oral Health toolkit, the Oral Health Foundation, and the Cochrane Library.
Brushing your teeth twice a day is essential -- but it only cleans about 60% of your tooth surfaces. The other 40%, the narrow spaces between your teeth where plaque builds up fastest, cannot be reached by any toothbrush.
That matters more than most people realise. The Adult Oral Health Survey 2023 found that 93% of UK adults had at least one sign of gum disease. Meanwhile, roughly one in three adults with natural teeth do not clean between their teeth at all.
This guide explains how to floss properly, how to use interdental brushes, which method is right for you, and what UK dentists actually recommend.
At a Glance: Interdental Cleaning Methods Compared
| Method | Best For | Effectiveness | Ease of Use | Approximate UK Cost |
|---|---|---|---|---|
| Interdental brushes | Most adults; medium to wide gaps | Highest (Cochrane 2019) | Easy | £3.50--£4.50 for 8-pack |
| Dental floss/tape | Tight gaps where brushes cannot fit | Good | Moderate -- needs technique | £1.50--£4.00 per pack |
| Water flosser | Braces, implants, limited dexterity | Good for gum health | Easy | £40--£80 for device |
| Super floss | Bridges, braces, wide gaps | Good (specialised) | Moderate | £4.00--£7.00 for 50 strands |
| Floss picks | On-the-go convenience | Adequate | Very easy | £2.00--£3.00 per pack |
| Soft picks | Sensitive gums, larger gaps | Limited evidence | Very easy | £3.00--£4.00 per pack |
Why Interdental Cleaning Matters
Your toothbrush, no matter how good it is, cannot physically reach between your teeth. Plaque accumulates in these spaces within hours, and if left undisturbed, it hardens into tartar (calculus) that can only be removed by a dental professional.
Over time, this bacterial plaque triggers gum inflammation (gingivitis), which -- if untreated -- can progress to periodontitis, a serious condition that destroys the bone supporting your teeth and is a leading cause of tooth loss in adults.
"Flossing isn't just for dislodging food wedged between your teeth. Regular flossing may also reduce gum disease, tooth decay and bad breath by removing plaque that forms along the gum line." -- NHS, Why Should I Use Dental Floss?
The scale of gum disease in the UK is significant:
| Statistic | Source |
|---|---|
| 93% of UK adults had at least one periodontal indicator | Adult Oral Health Survey 2023 (GOV.UK) |
| 28% of adults had pocketing greater than 3.5 mm | Adult Oral Health Survey 2023 |
| 42% of the UK population currently living with gum disease | PMC / The Conversation (2023) |
| Gum disease projected to affect 54% of UK adults by 2050 | Multi-state population model (PMC, 2023) |
| 27% of adults with natural teeth reported bleeding gums | Adult Oral Health Survey 2021 (GOV.UK) |
Gum disease has also been linked to cardiovascular disease, type 2 diabetes, and Alzheimer's disease. A Swedish study found severe periodontitis increases the risk of a first heart attack by 1.7 times and stroke by 2.1 times, even after adjusting for lifestyle factors.
What UK Dentists Actually Recommend
The official UK position is clear. The NHS, the Government's Delivering Better Oral Health toolkit (developed with the four UK Chief Dental Officers), and the Oral Health Foundation all recommend daily interdental cleaning.
"Clean daily between the teeth to below the gum line before toothbrushing." -- Delivering Better Oral Health, Chapter 8: Oral Hygiene
The toolkit specifies:
- Where there is space for an interdental brush, use one -- they are the preferred option
- For tight spaces where a brush cannot fit, use dental floss or tape
- Clean before brushing -- this is now the recommended sequence
- Daily -- once per day is sufficient, ideally in the evening
Most UK dental hygienists now recommend interdental brushes as the primary tool for most adults, with floss reserved for tight contact points where even the smallest brush cannot pass.
Interdental Brushes -- the UK's Preferred Method
Interdental brushes have overtaken traditional floss as the most popular cleaning method among UK adults. Research from the Oral Health Foundation's National Smile Month survey found that 34% of adults now use interdental brushes, compared with 31% using traditional floss.
The Cochrane Collaboration's 2019 systematic review of 35 randomised controlled trials (3,929 participants) concluded:
"Using floss or interdental brushes in addition to toothbrushing may reduce gingivitis or plaque, or both, more than toothbrushing alone. Interdental brushes may be more effective than floss." -- Cochrane Review 2019, Interdental Cleaning Devices
Why Brushes Are Often Better Than Floss
- They are easier to use -- the technique is simpler than flossing
- They clean a wider surface area in each pass
- They are reusable (rinse after use; replace when bristles splay)
- Most adults find them more comfortable than floss
- They work well even with moderate dexterity limitations
When Floss Is Still the Better Choice
- Between very tight teeth where even an ISO 0 (pink) brush cannot fit
- Between front teeth with narrow contact points
- When a dentist or hygienist specifically recommends it for your teeth
Many people use a combination: interdental brushes for most gaps and floss for one or two tight spots.
Interdental Brush Size Guide
Interdental brushes come in standardised sizes classified by ISO 16409. The most widely used system in the UK is TePe's colour-coded range, though colours are not standardised across all brands -- always check the millimetre size on the packet.
| Colour (TePe) | ISO Size | Wire Diameter | Best For |
|---|---|---|---|
| Pink | 0 | 0.4 mm | Very narrow gaps, tight front teeth |
| Orange | 1 | 0.45 mm | Narrow gaps |
| Red | 2 | 0.5 mm | Small gaps (common starting size) |
| Blue | 3 | 0.6 mm | Medium gaps (most widely used) |
| Yellow | 4 | 0.7 mm | Medium to larger gaps |
| Green | 5 | 0.8 mm | Larger gaps |
| Purple | 6 | 1.1 mm | Wide gaps |
| Grey | 7 | 1.3 mm | Very wide gaps |
| Black | 8 | 1.5 mm | Widest spaces |
How to Find Your Correct Size
- Start with a smaller size and gently insert between two teeth near the gum line
- Work up through sizes until you feel the bristles engaging snugly against both tooth surfaces
- The plastic-coated wire should not touch the sides of the teeth -- only the bristles
- If you feel discomfort or resistance, go back down one size
Most adults need two to three different sizes, because the gaps between front teeth are typically narrower than those between back teeth. Your dental hygienist can create a personalised brush chart showing the correct size for each space.
"You are likely to need two-three different sizes, or the combination of one-two brushes and floss -- it all depends on your spaces which normally vary throughout your mouth." -- TePe UK, Finding the Right Size Interdental Brush
When to replace: Replace an interdental brush when the bristles become splayed or worn. Some people replace weekly; heavy users may need to replace more often. Do not use regular toothpaste on interdental brushes -- the abrasives damage the bristles and can irritate your gums. Use water or a specialist interdental gel instead.
How to Use Interdental Brushes -- Step by Step
- Choose the correct size for the space you are cleaning (see size guide above)
- Hold the brush between your index finger and thumb, like a pen
- Work in front of a mirror -- this is essential for accurate positioning
- Insert gently at approximately 90 degrees to the tooth, close to the gum line
- Move the brush back and forth gently several times -- do not force it
- For back teeth, curve the neck of smaller brushes slightly, or bend the wire of larger ones gently to improve access
- Rinse the brush between teeth
- Do not bend the wire back and forth repeatedly -- this weakens it and shortens the brush's life
Clean between every tooth, including the back surface of your last molars. The whole process takes most people two to three minutes.
How to Floss Properly -- Step by Step
If some of your teeth are too tightly spaced for even the smallest interdental brush, dental floss or tape is the right tool. The technique matters -- incorrect flossing can damage your gums.
Choose Your Floss
- Waxed floss: Glides more easily between tight teeth; less likely to shred
- Unwaxed floss: Thinner; fits very narrow spaces but more prone to fraying
- Dental tape: Wider and flatter; gentler on sensitive gums
There is no clinically significant difference in effectiveness between waxed and unwaxed floss. The best type is whichever you will use consistently.
Step-by-Step Flossing Technique
- Cut 30--45 cm of floss -- roughly the length from your hand to your elbow
- Wind most of the floss around the middle finger of one hand, and a small amount around the middle finger of the other hand
- Hold 3--4 cm taut between your index fingers and thumbs
- Guide the floss gently between your teeth using a rocking motion -- never snap it down into the gums
- Curve the floss into a C-shape around each tooth, wrapping it against the tooth surface
- Slide gently up and down each tooth, going just below the gum line
- Use a fresh section of floss for each tooth to avoid spreading bacteria
- Clean both sides of every gap -- each space has two tooth surfaces
- Do not forget the back of your last molars
The NHS describes the motion as "a firm but gentle scraping of the tooth from top down."
Should You Clean Between Your Teeth Before or After Brushing?
Before brushing. This is now the clear recommendation from both the NHS and the Oral Health Foundation.
A randomised controlled trial found that cleaning between your teeth first, then brushing, produces significantly greater plaque reduction and allows higher concentrations of fluoride from toothpaste to reach between the teeth.
"Recent research has demonstrated that interdental cleaning before brushing is the best way to clean teeth effectively." -- Oral Health Foundation, Gum Disease
The logic is straightforward: interdental cleaning loosens plaque and debris from between teeth, then brushing sweeps it away and delivers fluoride to the freshly cleaned surfaces.
Common Mistakes to Avoid
| Mistake | Why It Is a Problem | What to Do Instead |
|---|---|---|
| Snapping floss into gums | Cuts and bruises gum tissue | Guide gently with a rocking motion |
| Only cleaning the top of the gap | Misses bacteria at the gum line | Curve floss below the gum line |
| Using the same section of floss throughout | Spreads bacteria from tooth to tooth | Advance to a fresh section each time |
| Flossing too aggressively | Causes gum damage and bleeding | Use light, consistent pressure |
| Forgetting the back of the last molars | Leaves two tooth surfaces uncleaned | Always clean the distal surface |
| Only cleaning before dental appointments | Plaque reforms within 24 hours | Clean daily for real benefit |
| Using regular toothpaste on interdental brushes | Abrasives damage bristles and gums | Use water or specialist gel |
| Forcing an oversized interdental brush | Damages gum tissue and causes pain | Start small and work up in size |
| Stopping because of bleeding | Allows bacteria to accumulate further | Keep going -- bleeding should stop within 1--2 weeks |
Bleeding Gums When You Start -- Is It Normal?
Yes -- light bleeding when you first start or restart interdental cleaning is common. It should improve within one to two weeks of consistent daily cleaning.
Why it happens: Plaque bacteria cause gum inflammation (gingivitis). Inflamed gums have fragile blood vessels that bleed easily when disturbed. The bleeding is a sign that the area needs cleaning, not that you should stop.
The worst thing you can do is stop. Avoiding the area allows more bacteria to accumulate, which worsens the inflammation and bleeding over time. Continue cleaning gently every day, and the bleeding should resolve as your gums heal.
When to See a Dentist About Bleeding Gums
Book a dental appointment if:
- Bleeding continues beyond two weeks of daily, gentle cleaning
- Bleeding is heavy rather than light spotting
- Bleeding increases rather than improves
- You notice additional symptoms: gum recession, loose teeth, persistent bad breath, pus, or pain
- Bleeding occurs spontaneously, not just during cleaning
Your dentist or hygienist can assess whether you have gingivitis (reversible with improved cleaning) or periodontitis (requires professional treatment).
Interdental Care for Braces, Bridges, and Implants
Braces and Orthodontic Appliances
Orthodontic wires and brackets trap food and plaque, significantly increasing the risk of tooth decay and gum disease during treatment.
Recommended tools:
- Super Floss (such as Oral-B Super Floss) -- the stiffened end threads under orthodontic wire, the spongy middle cleans around brackets, and the regular floss section cleans between teeth
- Small interdental brushes -- can clean around bracket bases and between wire and tooth surfaces
- Water flossers -- particularly useful for orthodontic patients. The Oral Health Foundation notes water flossers are "a particularly useful option for those fitted with orthodontic braces"
- Floss threaders -- allow regular floss to pass under orthodontic wire
Dental Bridges
The pontic (false tooth) in a bridge sits on the gum ridge, and plaque accumulates underneath it. Regular floss cannot reach this area without a threader.
Recommended approach:
- Use super floss or a floss threader to pass floss under the bridge pontic
- Clean under the pontic with the spongy section using a gentle back-and-forth motion
- Use interdental brushes around the abutment teeth (the teeth supporting the bridge)
- A water flosser is an excellent supplement for flushing debris from under bridges
Dental Implants
Implants require careful interdental maintenance to prevent peri-implantitis -- inflammation around the implant that can lead to implant failure.
The Scottish Dental Clinical Effectiveness Programme (SDCEP) recommends:
"Patients should use a gentle flossing technique and the floss should not be forced below the peri-implant mucosal margin." -- SDCEP, Implant Oral Hygiene
Key guidance for implant patients:
- Use plastic-coated interdental brushes to avoid scratching the implant surface
- If you have exposed implant threads, avoid floss products entirely -- use interdental brushes instead, as floss can shred on rough threads and leave debris that worsens inflammation
- Attend professional check-ups every six months
Limited Dexterity -- Elderly Patients and Arthritis
If you have reduced grip strength or limited hand movement:
- Interdental brushes are generally easier than floss -- the handle is larger and the motion simpler
- Water flossers are an excellent alternative for patients who struggle with manual tools
- Floss holders (pre-threaded Y-shaped picks) enable single-handed flossing
- Rest your elbow on the basin to reduce fatigue, or sit down with a bowl if standing is tiring
- TePe's Extra Grip range was developed with qualified occupational therapists for patients with reduced dexterity
When to See a Dental Hygienist
A dental hygienist provides professional cleaning that goes beyond what you can achieve at home. They use specialist instruments to remove tartar (hardened plaque) from above and below the gum line -- something no toothbrush, floss, or interdental brush can do.
Signs You Should Book a Hygienist Appointment
- Persistent bleeding gums despite two or more weeks of daily interdental cleaning
- Visible tartar build-up (hard, yellowish deposits on teeth)
- Gum recession or sensitivity around the gum line
- Bad breath that persists despite good home care
- Gum pain, swelling, or puffiness
- Teeth that feel loose or have shifted position
What a Hygienist Does
- Scaling: Removes tartar from tooth surfaces and below the gum line
- Root surface debridement: Deep cleaning for periodontitis
- Personalised brush chart: Shows the correct interdental brush size for each gap in your mouth
- Oral hygiene instruction: Demonstrates techniques tailored to your teeth, dexterity, and dental work
- Monitoring: Tracks gum health at each visit to detect changes early
How Often Should You See a Hygienist?
- General guidance: Every six months for patients with no active gum disease
- Active gum disease: Every three months (maintenance phase)
- NHS: Visit frequency is determined by clinical need; NICE recommends personalised intervals of 3 to 24 months based on risk
How Much Does a Hygienist Appointment Cost?
| Type | Cost | Notes |
|---|---|---|
| NHS (Band 1) | £27.90 | Only if clinically necessary; not routine |
| Private (most of UK) | £60--£90 | Standard hygiene appointment |
| Private (London/South East) | £90--£150+ | Longer or more complex visits |
| Private (Midlands/North/Wales) | £50--£90 | Comparable services |
For a detailed breakdown of hygienist costs, see our Dental Hygienist Cost UK guide.
Where to Buy Interdental Products in the UK
| Product | Approximate Price | Where to Buy |
|---|---|---|
| TePe Original Brushes (8-pack) | £3.50--£4.50 | Boots, Superdrug, Amazon |
| TePe Mixed Pack (8 assorted sizes) | £3.50--£4.30 | Widely available -- good starter option |
| Wisdom Clean Between Pro (30-pack) | Around £2.00 | Morrisons, supermarkets |
| Oral-B Interdental Brushes | £3.00--£5.00 | Boots, supermarkets, Amazon |
| Dental floss (standard) | £1.50--£4.00 | Supermarkets, pharmacies |
| Oral-B Super Floss (50 pre-cut strands) | £4.00--£7.00 | Amazon UK, Boots |
| Waterpik Water Flosser | £40--£80 | Amazon UK, Boots, Currys |
Note: Interdental brushes are not available on NHS prescription. They must be purchased over the counter.
Most TePe products are available in supermarkets (Tesco, Sainsbury's, Morrisons), pharmacies (Boots, Superdrug, Lloyds), and online retailers. Your dental hygienist may also sell them directly at your appointment.
Frequently Asked Questions
How often should I floss or use interdental brushes?
Once a day is sufficient. The NHS and Delivering Better Oral Health toolkit both recommend daily interdental cleaning. Most dental professionals suggest the evening as the best time, as part of your bedtime routine.
Should I floss before or after brushing?
Before brushing. Research shows that cleaning between your teeth first loosens plaque and debris, allowing your toothpaste's fluoride to penetrate more effectively when you brush afterwards. Both the NHS and the Oral Health Foundation now recommend this sequence.
Is it normal for my gums to bleed when I floss?
Light bleeding when starting or restarting interdental cleaning is common. It is a sign of gum inflammation and should improve within one to two weeks of consistent, gentle daily cleaning. If bleeding persists beyond two weeks or is heavy, see your dentist.
What size interdental brush should I use?
Most adults need two to three different sizes -- front teeth gaps are usually narrower than back teeth gaps. Start with a smaller size and work up until the bristles fit snugly without forcing. A dental hygienist can create a personalised size chart for your mouth.
Are interdental brushes better than floss?
For most people, yes. The Cochrane 2019 review of 35 randomised controlled trials found interdental brushes may be more effective than floss at reducing gingivitis. They are also easier to use. However, floss is still the better choice for very tight gaps where even the smallest brush cannot fit. Many people use both.
Can children use interdental brushes or floss?
The NHS recommends that children can start using dental floss or interdental brushes from age 12. However, children should begin cleaning between teeth as soon as two teeth are touching -- parents can help younger children. From around age seven or eight, children can practise with close supervision.
Should I use toothpaste on my interdental brush?
No. Regular toothpaste is abrasive and will damage the bristles and potentially irritate your gums. Use water, or a specialist interdental gel if your hygienist recommends one.
Is a water flosser as good as regular flossing?
Water flossers are effective for reducing gum inflammation and are particularly useful for people with braces, bridges, implants, or limited dexterity. The Oral Health Foundation has approved the Waterpik brand. However, current evidence suggests interdental brushes remain the most effective method for most people. A water flosser is an excellent supplement or alternative if manual tools are difficult for you.
Find a Dentist or Hygienist Near You
Good interdental cleaning at home is the foundation, but regular professional care is essential too. A dental hygienist can remove tartar that home cleaning cannot reach, demonstrate the best technique for your teeth, and help you choose the right interdental brush sizes.
Use our search to find a dentist or hygienist near you and book your next appointment.
