Water flosser: what it does, whether it removes tartar, and how to use it

A water flosser shoots a thin, pressurized stream of water between your teeth and along the gumline to flush out bits of food. It adds to brushing; it doesn’t replace it. And it doesn’t remove tartar: only a professional cleaning at the dental office can do that. It’s especially useful if you have implants, a bridge or braces, or if string floss just doesn’t work for you.

It goes by several names (water flosser, oral irrigator, dental water jet) and comes in two types: countertop and cordless. Below you’ll find what the studies say it does, whether it removes tartar, when it’s worth it compared with floss, how to use it step by step, and what to look for when you choose one.

What a water flosser is and what it does

It’s a device with a water tank, a small motor and a tip. The motor pushes water through the tip while you guide it along the gumline and through the gaps between your teeth.

The American Dental Association (ADA) lists it among interdental cleaners, along with floss, interdental brushes and plastic picks. They all help remove food trapped between your teeth and the film of bacteria that builds up along the gumline before it hardens.

Those spaces between your teeth matter because a toothbrush doesn’t reach them well. According to the ADA, bristles alone don’t clean those tight gaps properly, and the plaque left there can harden into tartar.

Does a water flosser remove tartar?

No. Tartar is hardened plaque that sticks to the tooth above and below the gumline, and no toothbrush, floss or jet of water can scrape it off. The ADA and Cleveland Clinic agree that only a dentist or a dental hygienist can remove it, with a professional cleaning. It usually looks yellowish at first and darkens over time.

In theory, a water flosser flushes away soft plaque before it hardens, like other interdental cleaners. In practice, studies haven’t found that it reduces plaque more than brushing alone, as you’ll see in the next section.

If you can already feel a hard layer along your gums, what you need is an oral cleaning at the clinic: it costs €30 and takes about 30 minutes, with ultrasonic scaling for the tartar, then polishing and fluoride to finish.

Water flosser vs. floss: what the evidence says

The key reference is a 2019 Cochrane review that pooled 35 trials with 3,929 adults. Here’s what it found about using a water flosser in addition to brushing:

• It may reduce gum inflammation (gingivitis) after one month, with very low-certainty evidence, and that effect wasn’t seen at three or six months.
• It didn’t reduce plaque or the number of bleeding gum sites any more than brushing alone.
• Compared with floss, it might reduce gingivitis slightly more at one month, again with low- or very low-certainty evidence, and with no difference in plaque.
• No study recorded serious side effects from these devices.

The same review concludes that floss and interdental brushes, added to brushing, may reduce gingivitis, plaque or both more than brushing alone, and that interdental brushes may work better than floss. The authors point out that almost all the studies were short and involved people with little inflammation to begin with, and that the differences may not be noticeable in everyday life.

What this means for you: if you already use floss or interdental brushes well, a water flosser adds little. If you skip cleaning between your teeth because flossing feels like a chore, a water flosser is an easier way to do it, even though the evidence that it makes a difference is weak.

When a water flosser makes more sense

Mainly where floss is hard to thread or can’t reach:

• Implants. In peri-implant mucositis, which is inflamed gum tissue around an implant, two small trials found improvements when a water flosser was added to home care.

  • In one, with 60 patients, mucositis was still present at 12 weeks in 50% of those who only had a professional cleaning and hygiene instructions, in 35% of those who added a water flosser with plain water, and in 5% of those who used it with 0.06% chlorhexidine.
  • In another, with 45 patients, gum bleeding dropped more with a water flosser plus a toothbrush than with the toothbrush alone.

  If the gum around an implant bleeds or swells, it’s worth knowing what peri-implantitis is and not letting it slide.

• Bridges and fixed prosthetics. Under a bridge, floss only gets through with a floss threader; the stream of water gets there without one.
• Braces. Threading floss under the wire takes time. A water flosser flushes out the debris that collects between the wire and the tooth, although brushing is still the core of your routine.
• If floss is hard for you. People with limited hand mobility, or who simply can’t get the hang of it.

If your gums are red or bleed when you brush, a water flosser won’t fix the cause.

The NHS, the UK’s public health service, explains that gum disease is treated according to how advanced it is: in the early stages, better oral hygiene and a cleaning are enough, and if it’s more serious, you may need a deep cleaning below the gumline. To find out where you stand, you need a periodontal checkup.

How to use a water flosser step by step

1. Fill the tank with lukewarm water.
2. Attach the tip and start on a low pressure setting. Turn it up gradually as you get used to it.
3. Lean over the sink, put the tip in your mouth and close your lips partway so you don’t splash. Let the water drain into the sink.
4. Turn the unit on and guide the tip along the gumline, pausing briefly at each gap between your teeth, on the outside and on the inside.
5. Start with your back teeth and always follow the same order so you don’t miss any area.
6. When you’re done, empty the tank and let the tip dry.

The ADA recommends brushing twice a day and cleaning between your teeth once a day, with floss or another interdental cleaner. Don’t add anything to the water unless your dentist tells you to: the chlorhexidine trial was run under clinical supervision, and a 2017 Cochrane review reports that this antiseptic stains teeth and can change your sense of taste.

Cordless or countertop water flosser: pressure, tank and tips

No single model suits everyone. These are the differences that matter:

• Countertop or cordless. A countertop model plugs into the wall and has a large tank that covers your whole mouth without a refill. A cordless one runs on a battery, fits in a toiletry bag and works for travel, but its tank is small and you may need to refill it halfway through.
• Pressure. What helps is having several pressure levels, so you can start low and turn it up as your gums allow.
• Tips. The standard tip works for almost everything. There are tips with a small brush for braces and fine tips for the gumline or around implants.
• Maintenance. Look for a tank that’s easy to empty and clean, and for replacement tips that are easy to find.

If you want to know whether a water flosser is worth it for your mouth or whether floss is enough, we’ll tell you at your checkup. The first visit and the quote are free.

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