Interdental brush or water flosser: which to choose?

Choosing between these two tools isn't always easy. Both aim for the same thing: taking over from your toothbrush for a deep interdental clean. But that's where the similarities end.

In the lines below, we'll explain what sets them apart, their strengths, and above all, help you work out which one might suit you best.

While an electric toothbrush removes a large part of dental plaque, it remains insufficient for interdental spaces. Indeed, the bristles can't reach the small, tight spaces between our teeth. As a result, food debris and dental plaque build up there.

According to the French Union for Oral Health (UFSBD), 40% of our tooth surface escapes brushing. This explains why cavities and gum irritation so often take hold in these spots.

Neglecting interdental cleaning means taking certain risks:

• Plaque builds up and hardens,

• Cavities form between the teeth,

• The gums can become red, swollen and bleed easily (gingivitis),

• Over time, this can develop into periodontitis, a more serious condition that threatens the stability of the teeth.

It's a small cylindrical or slightly conical brush, with a flexible metal core and soft bristles. This interdental brush is specially designed to slide between your teeth and remove what a regular toothbrush can't reach.

It comes in several sizes to fit all interdental space widths. Choosing the right size matters: too small, and it won't clean well; too large, and it risks irritating your gums.

You don't need to be an expert, but a bit of care goes a long way:

• Gently slide it between two teeth,

• Move it back and forth a few times, without forcing,

• If it doesn't fit, the space may be too narrow — in that case, it's best not to force it.

It works by mechanically loosening dental plaque and food residue. Once a day is enough, preferably in the evening, whether before or after your usual brushing.

The interdental brush offers several advantages:

• It's incredibly effective against plaque,

• Its mechanical action is direct and effective,

• It's ideal if your teeth are fairly spaced apart,

• It's often recommended for gum problems or periodontitis.

In fact, some studies show it can be more effective than dental floss at reducing gum inflammation, especially when the spaces are a bit open.

Like any tool, it also has its downsides:

• It's not suited to very tight spaces,

• You need to find the right size,

• It can take a little time to get used to it,

• Incorrect use can cause slight bleeding.

With a bit of practice, and sometimes some advice from your dentist, it quickly becomes second nature for truly thorough oral hygiene.

Also known as an oral irrigator, this is a small electric device that sprays water to clean between the teeth. It usually consists of a water reservoir, a propulsion system and an adjustable nozzle. On some models, you can even adjust the pressure and choose from different nozzles, for example for sensitive gums, braces or implants.

Unlike an interdental brush, there's no direct mechanical contact with the teeth; it's the water that does the work.

The principle is simple: the device sends small pulses of water between the teeth and under the gumline. This dislodges food residue, disrupts bacterial plaque and gently stimulates blood circulation.

To use it properly, you need to:

• Fill the reservoir with lukewarm water,

• Aim the nozzle at the line where the teeth meet the gums,

• Move it slowly along the teeth, without lingering too long in the same spot.

A tip: always start with low pressure, then increase it gradually to whatever feels comfortable for you.

The oral irrigator offersseveral advantages:

• It's very gentle on the gums,

• Easy to fit into your daily routine,

• Perfect for reaching hard-to-access corners,

• Suitable if you wear braces or have implants.

Many people with sensitive or easily bleeding gums tolerate it better than a traditional interdental brush.

Despite its strengths, it doesn't do everything:

• It can be less effective on heavily hardened plaque,

• It's sometimes less precise than an interdental brush in large gaps,

• It requires a plugged-in device (so less practical while travelling),

• It requires a short adjustment period.

That's why it's often seen as an excellent complement to brushing and interdental brushes, rather than a full replacement.

Today, the interdental brush remains the go-to for removing dental plaque. Its mechanical action cleans deeply, especially between well-spaced teeth, dislodging stubborn bacteria.

The oral irrigator, on the other hand, works differently: a pressurised jet of water flushes out food residue and disrupts bacteria. But be careful, it's often less effective on plaque that's already well established.

The interdental brush helps reduce inflammation by removing the plaque responsible for gingivitis. It's also often recommended for periodontal problems.

The oral irrigator has a massaging effect that stimulates blood circulation in the gums, which helps strengthen them.

What we observe:

• Both tools can reduce bleeding,

• The oral irrigator is often more pleasant to use,

• The interdental brush remains more precise and targeted.

Ease of use plays a key role in your choice.

With the interdental brush, there's a bit of a learning curve:

• Find the right size,

• Master the technique,

• Insert it gently.

The oral irrigator, meanwhile, is often seen as simpler:

• Quick to get the hang of,

• Intuitive to use,

• No need to be as precise.

Your personal profile guides the choice.

The interdental brush is ideal:

• If your teeth are well spaced apart,

• In case of periodontitis,

• If you're looking for maximum effectiveness against plaque.

The water flosser, on the other hand, is better suited:

• For sensitive gums,

• If you wear braces,

• If you prioritise comfort and simplicity.

If you have visible interdental spaces, the interdental brush is often the right choice. Thanks to its shape, it cleans directly along the tooth surfaces, for a deep result.

It's particularly useful:

• If you've lost gum papilla,

• After periodontal treatment,

• When food tends to get stuck.

If your gums are sensitive, bleed easily or hurt, the water flosser can be an excellent option. Its action is gentle and cleans without irritating.

It's often recommended:

• In case of mild gingivitis,

• After a procedure at the dentist,

• If you don't tolerate interdental brushes well.

It's also very handy when access between the teeth is tricky, for example with braces, a bridge or implants.

The water reaches corners that are hard for an interdental brush to access, especially around wires and brackets. It then becomes a real ally for avoiding plaque build-up and preventing inflammation.

Often, there's no need to pit the interdental brush against the oral irrigator — the two can complement each other:

• The interdental brush removes stubborn plaque,

• The water flosser rinses and cleans gently.

Combining them can be ideal for optimal hygiene, especially if you have specific needs or delicate gums.

All dentists agree: cleaning between the teeth is essential, whatever the tool. But in practice, the interdental brush is often recommended first, given how proven its mechanical action against plaque is.

Their concrete advice is as follows:

• Favour a tool that acts mechanically to dislodge plaque,

• Choose a shape and size suited to your mouth,

• Don't hesitate to ask your dentist to tell you the right size of interdental brush.

the oral irrigator, meanwhile, is often presented as an excellent complement, or an alternative in particular situations: sensitive gums, wearing braces or having implants.

Health authorities, such as the French UFSBD, are clear: interdental cleaning should be part of your routine, every single day. Without it, even the most thorough brushing leaves 40% of tooth surfaces uncleaned.

The benefits of this kind of consistency are tangible:

• Considerably reduced plaque,

• Gums that bleed much less,

• Effective prevention of more serious gum problems.

More and more professionals advocate a combined approach rather than having to choose between one or the other.

• The interdental brush "scrapes" mechanically along the tooth surfaces to lift away plaque.

• The water flosser allows for deep rinsing and a gentle gum massage, for comfort and a fresh feeling.

• Used together, they provide truly optimal interdental hygiene.

This combination is particularly wise for people at higher risk of gum problems, or those with implants or braces.

To avoid hurting yourself and get the most out of its benefits, it's important to use your interdental brush correctly.

Here's how to proceed, step by step:

• Choose a size suited to the space between your teeth,

• Insert the interdental brush gently, without forcing,

• Make gentle back-and-forth movements,

• Rinse it well after each use.

Above all, never force it. If it doesn't fit, it's probably too big for the space.

It's fairly easy to get the hang of, but a few good habits will help you get the most out of it:

• Fill the reservoir with lukewarm water,

• Start with low pressure,

• Aim it at a right angle (90°) toward the gum,

• Run it along your teeth, without lingering too long in the same spot.

With practice, you'll be able to adjust the pressure to suit your sensitivity and comfort.

For truly effective oral hygiene, consistency is key. Here's what's generally recommended:

• Use the interdental brush once a day,

• Complete with the oral irrigator once a day, or as needed,

• Add this cleaning step to your evening routine.

The ideal time remains before bed, to remove all the residue built up throughout the day.

More and more dentists recommend using them together. The interdental brush works mechanically to dislodge stubborn plaque, while the oral irrigator rinses deeply, clears away small residues and even gently massages the gums. The clean is more thorough, without taking hours.

This combination is particularly worthwhile in certain situations:

• If you have sensitive gums or a history of periodontitis,

• When you wear an implant, a bridge or braces,

• If the spaces between your teeth are irregular,

• Or following a specific dental treatment.

In these cases, combining both methods helps better protect at-risk areas and look after your gums over time.

Between the interdental brush and the oral irrigator, it all depends on your mouth, the sensitivity of your gums and what feels most practical for you day to day.

The interdental brush remains the most effective at removing plaque, especially if your interdental spaces are a bit wide.

The oral irrigator, meanwhile, wins people over with its gentle, easy nature, particularly appreciated if your gums are delicate or you wear braces.

Rather than pitting them against each other, you can also combine them. Together, they allow for a more thorough clean.

The most important thing is to find a routine that suits you and stick to it. Regular cleaning between the teeth, on top of good brushing, is one of the best habits for taking care of your teeth and gums over the long term.