Flossing vs. Interdental Brushes: Which Is Better?
Most people in St. John's who brush twice a day still leave nearly 40% of each tooth's surface untouched. That gap, literally between your teeth, is where cavities quietly form and gum disease starts. If you have been wondering whether your flossing routine is actually doing the job, or whether those little interdental brushes are worth switching to, the answer is not one-size-fits-all. The right tool depends on the shape of your gum tissue, the gaps between your teeth, and what dental work you already have. If you have been getting contradictory flossing tips in St. John's from every source you read, this guide cuts through the noise.
Table of Contents
Quick Takeaways
Key Insight | Explanation |
|---|---|
Interdental brushes outperform floss for gum health | Research shows interdental brushes produce more consistent reductions in gum inflammation than string floss, especially in people with open interdental spaces. |
Floss wins in tight contacts | When teeth sit close together with little gap, string floss is the only tool thin enough to slide through without damaging the gum tissue. |
Size selection matters enormously for brushes | An interdental brush that is too small will miss plaque. One that is too large will irritate the gums. Your dentist can size you properly in about two minutes. |
Technique beats frequency | Flossing incorrectly every day produces poorer results than correct technique done five times a week. The same is true for interdental brushes. |
Implants and bridges need interdental brushes | String floss cannot reliably clean around implant components or beneath bridge pontics. Interdental brushes and specialist floss threaders are the preferred tools here. |
Using both tools is the best approach for most adults | Floss clears tight contacts, and interdental brushes clean open spaces and around restorations. Combining them covers the most surface area. |
Consistency beats perfection | A simple routine you actually follow every night produces better long-term outcomes than an elaborate one you skip three days a week. |
What Floss Actually Does
String floss is designed to do one specific thing very well: slide into the narrow contact point between two teeth and scrape the surfaces that face each other. The motion is vertical, not just back and forth, and when done correctly, the floss wraps in a C-shape around each tooth surface and dips just below the gum line to disrupt the bacteria that collect in the sulcus.
For most people with tight or closely spaced teeth, dental floss remains the only realistic option. Interdental brush bristles simply cannot fit into a contact point that is half a millimetre wide without shredding or forcing the gum tissue apart. Floss is also the better choice after cosmetic bonding on front teeth, where the gaps are often sealed completely.
Types of Floss Worth Knowing About
Waxed floss slides more easily through tight contacts and is less likely to shred on rough fillings or older crowns. Unwaxed floss tends to fan out slightly, which some patients find gives a better cleaning sensation against the tooth surface. Tape-style floss, which is wider and flatter, works well if your contacts are slightly looser or your gums bleed easily, since it distributes pressure more gently.
Floss picks and floss threaders are two specialized formats. Picks are convenient for on-the-go use but do not allow the C-shape wrap technique as effectively as hand-held floss. Threaders are essential for patients with dental bridges, as they allow the floss to pass beneath the pontic and clean the underside of the restoration.
Pro tip: Use about 45 cm of floss and wind most of it around your middle fingers, leaving only 3 to 5 cm of clean floss to work with at a time. Advancing to a fresh section as you move between teeth prevents you from redistributing bacteria from one space to another.
What Interdental Brushes Actually Do
Interdental brushes are small cylindrical or tapered brushes mounted on a short handle. They are pushed horizontally through the space between teeth rather than pulled vertically like floss. This horizontal motion means the bristles contact a larger surface area of both tooth faces simultaneously, and the brush also physically massages the gum tissue as it passes through.
This is why interdental brushes tend to work better in mouths that have open interdental spaces, which typically means adults over 30 whose gum tissue has receded slightly with age, patients who have undergone orthodontic treatment, and anyone with dental implants, crowns with wider margins, or large restorations. For these patients, a standard piece of floss hangs loosely in the space and does not make firm contact with both tooth surfaces.
Choosing the Right Brush Size
Interdental brushes come in standardized ISO sizes, typically coded by colour. The brush should fit snugly but should not require force to pass through the space. If you have to push hard, the brush is too large and will injure the gum tissue. If the brush passes through without any resistance, it is too small and will not remove plaque effectively.
Most adults require different sizes for different areas of the mouth. The spaces between front teeth are often narrower than the spaces further back along the arch. Your dentist or hygienist can identify the right sizes for each zone during a routine cleaning appointment at Stavanger Dental.
An L-shaped interdental brush is particularly effective for reaching the spaces between upper and lower molars, where the straight style can be awkward to angle correctly.
Pro tip: Do not rinse an interdental brush under water between teeth during a session. The bristles hold the loosened plaque, and rinsing mid-session disperses bacteria back into the mouth. Wipe the brush on a tissue instead, then rinse the entire brush thoroughly at the end.
What the Evidence Says
The research on this topic has become increasingly clear over the past decade. A review published through the Dental Health Foundation found that interdental brushes tend to improve gum health slightly more than floss in the short term, with more consistent reductions in gum inflammation scores. The benefits appear greatest in people with gum disease or open interdental spaces, where brushes can physically contact more tooth surface than floss.
The most meaningful measure of interdental cleaning is not which tool you use, but whether the tool you choose actually contacts the tooth surface you are trying to clean. Picking the wrong tool for your anatomy means the plaque stays, regardless of how consistently you use it.
A study comparing interdental brushes and dental floss in patients with moderate to severe periodontitis found that over a six-week period, interdental brushes reduced approximal plaque scores more substantially than dental floss. Importantly, research from a large published analysis found that compared to traditional dental floss, interdental brushes demonstrated notably superior effectiveness in reducing gingival inflammation, with reductions in the range of 40% for both inflammation and plaque buildup.
However, these results come with an important qualifier. In unsupervised real-world studies, where technique is not controlled and patient compliance varies, the differences between tools shrink considerably. The best tool remains the one you will actually use correctly and consistently.
What This Means for Different Patients
For patients with healthy gums, tightly packed teeth, and no restorations, floss performs well and remains appropriate. For patients with any history of gum disease, open spaces, crowns, bridges, or implants, the evidence favours interdental brushes, or a combination of both tools.
Choosing the Right Tool for Your Mouth
The single most common mistake patients make is choosing a cleaning tool based on what their parents used, or what was cheapest at the pharmacy, rather than what their own mouth actually needs. Your oral anatomy, your existing dental work, and your history of gum disease are the three deciding factors.
When Floss Is the Better Choice
Choose string floss as your primary oral hygiene tool if your teeth are tightly spaced with little to no visible gap between them, if you have had cosmetic bonding on your front teeth, if you are a teenager or young adult whose gum tissue has not yet receded at all, or if your dentist has confirmed that your gum health is good and your interdental spaces are narrow.
When Interdental Brushes Are the Better Choice
Switch to interdental brushes, or add them to your routine, if you have been diagnosed with gingivitis or periodontitis, if you have dental implants, fixed bridges, or orthodontic retainers, if your gums have receded and your dentist in St. John's NL can see visible triangular gaps between your teeth at the gumline, or if you find flossing physically difficult due to dexterity limitations.
When Using Both Makes Sense
Many adults benefit from a combined approach: floss in the front of the mouth where contacts are tight, and interdental brushes along the back teeth and around any crowns or implants. This is not overcompliance. It reflects the real variation in anatomy across a single mouth. A brief conversation with the team at Stavanger Dental during your next preventive visit can help map out which tool belongs where in your specific case.
Comparison: Floss vs. Interdental Brushes vs. Using Both
Factor | String Floss | Interdental Brushes | Combination Approach |
|---|---|---|---|
Best for tight contacts | Yes, the only effective option | No, bristles cannot fit | Floss handles tight zones |
Best for open spaces | Passes through without full contact | Yes, bristles contact both surfaces | Brushes handle open zones |
Gum inflammation reduction | Moderate | Superior in most studies | Best overall coverage |
Ease of use for molars | Difficult to angle correctly | L-shaped brushes work well | Use brushes for molars |
Suitability for implants or bridges | Limited, threaders required | Yes, preferred method | Brushes around restorations |
Cost | Low | Moderate (reusable short-term) | Moderate overall |
Evidence strength | Strong for tight contacts | Strong for open spaces and gum disease | Best supported by current evidence |
Common Mistakes That Make Both Tools Less Effective
The gap between knowing you should clean between your teeth and actually doing it well is where most oral health problems begin. Understanding the technique errors saves you time and prevents damage.
Flossing Mistakes
Sawing back and forth at the contact point instead of sliding the floss straight down in one motion is the most common error. Sawing snaps the floss against the gum and causes the bleeding that makes people avoid flossing in the first place. The correct motion is a gentle downward entry, a C-wrap around each tooth surface, and a smooth vertical scraping motion, not a horizontal one.
Stopping at the gum line is another mistake. The floss needs to dip just below the gum margin to disrupt the bacteria in the sulcus. This should not hurt. If it does, the gum tissue is inflamed, which is the exact reason you need to clean there more carefully, not more gently.
Interdental Brush Mistakes
Using a single brush size for the entire mouth is the most frequent error. Most people need at least two sizes. Using too much force to push a brush through a space that is too small for it tears the gum tissue and causes recession over time, which is the opposite of the intended benefit.
Replacing brushes too infrequently is also a problem. Once the bristles splay, the brush has lost its shape and is no longer contacting the tooth surface effectively. Replace brushes when the bristles show visible wear, typically after a few days of consistent daily use.
Pro tip: If your gums bleed when you start using interdental brushes, do not stop. Bleeding from healthy gums during correct cleaning usually settles within one to two weeks as the inflammation reduces. Persistent bleeding after two weeks is a signal to book a preventive care appointment in St. John's to assess your gum health.
Frequently Asked Questions
Are interdental brushes better than flossing for everyone?
No. Interdental brushes are superior for patients with open interdental spaces, gum disease, or dental restorations like implants and bridges. For patients with tightly packed teeth and no restorations, string floss remains the most appropriate tool because interdental brush bristles cannot physically fit into a narrow contact point without causing damage.
How often should I use interdental brushes or floss?
Once daily is the clinical recommendation for both tools. Cleaning between your teeth at night, before bed, is generally considered the most important time, since it removes the food debris and plaque that would otherwise remain undisturbed for eight or more hours while you sleep. Twice daily is fine if you prefer it, but once daily done correctly is more valuable than twice daily done poorly.
Can I use interdental brushes if I have braces or a retainer?
Yes, and interdental brushes are often more effective than floss around orthodontic appliances. Threaded floss can be difficult to work around brackets and wires, while a small interdental brush can clean around each bracket and into the spaces beneath the archwire more efficiently. Your dental team at Stavanger Dental can recommend the best size and style for your specific appliance.
My gums bleed when I floss. Should I stop?
In most cases, no. Bleeding gums during flossing are a sign of inflammation caused by the very plaque you are trying to remove. Stopping makes the situation worse, not better. Continue with correct technique and the bleeding should reduce within one to two weeks. If it does not, or if bleeding is heavy, book an appointment to check for underlying gum disease rather than avoiding the area.
What is the right size interdental brush to use?
The right size fits snugly between your teeth without requiring force. Most adults need more than one size because different areas of the mouth have different gap widths. Interdental brushes come in colour-coded ISO sizes ranging from very fine to wide. A dentist or hygienist can identify the correct size for each zone of your mouth during a routine visit, which is a much more accurate approach than guessing at the pharmacy.
Does the Canadian Dental Care Plan cover preventive care like cleanings where my hygienist can guide my technique?
Stavanger Dental in St. John's accepts the Canadian Dental Care Plan. Preventive care, including hygiene appointments where your team can assess your interdental cleaning technique and recommend the right tools for your specific mouth, may be covered under your plan. It is worth checking your coverage details and booking a preventive visit to get personalized guidance rather than relying on general advice.
Is water flossing a valid alternative to string floss or interdental brushes?
Water flossers are a useful supplementary tool, particularly for patients who find manual interdental cleaning difficult due to dexterity issues or who have complex dental work. However, current evidence positions water flossers as complementary rather than a direct replacement for contact-based cleaning. They flush debris effectively but do not produce the mechanical scraping action against the tooth surface that both string floss and interdental brushes provide.
Have you recently switched between flossing and interdental brushes, or found a combination that works well for you? Share your experience in the comments below.
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