· 7 min
Water flosser or dental floss? It is one of the questions we hear most often in the clinic, and it usually comes with a second one: if I buy a water flosser, can I stop flossing? The short answer is that both clean between the teeth, that in head-to-head comparisons the water flosser performs as well as or better than floss for gum health, and that neither replaces the toothbrush. The right tool depends on the spaces between your teeth and on which one you will actually use every day.
A water flosser, also called an oral irrigator, is a device that delivers a thin, pressurized stream of water, usually pulsating. You aim it at the line where the gum meets the tooth and at the spaces between teeth, and it flushes out food debris and part of the biofilm, the layer of bacteria that builds up on teeth over the day.
Its clearest effect is on gum inflammation. A scoping review covering 275 sources concluded that oral irrigation consistently reduces periodontal inflammation, while its results on plaque are mixed (Sarkisova et al., 2024). Put simply, it leaves the gums healthier, even if it does not always remove all the attached plaque.
Floss reaches the contact point between two teeth, where a toothbrush cannot go, and wipes plaque off the side surfaces. Used properly, it works. In the Cochrane review on interdental cleaning, which included 35 clinical trials, adding floss to toothbrushing reduced gingivitis at one month compared with brushing alone, although the certainty of the evidence was low (Worthington et al., 2019).
The weak point of floss is technique and consistency. It takes dexterity and time, and used poorly it skips the area that matters or injures the gum. That is why so many people give it up within a few weeks. With braces, fixed bridges or implants it becomes even slower, because it has to be threaded under the wire or under the restoration.
When the two are compared directly, the results lean toward the water flosser, without a large margin:
These findings deserve a careful reading. Most studies last weeks, not years, and the Cochrane review rates the evidence as low or very low certainty. What every study does agree on is that cleaning between the teeth, with whatever tool, beats not doing it.
For many people, yes, it can replace floss as the main way to clean between the teeth, especially if flossing never became a habit. A water flosser used every night cleans more than floss left in a drawer.
There are exceptions. If your teeth are very tight and food gets trapped at the contact point, water may not be enough to dislodge it, and floss is still useful. If instead you have more open spaces between teeth, for example from receding gums, a correctly sized interdental brush usually cleans better than either. What a water flosser never replaces is brushing twice a day with a fluoride toothpaste.
The water flosser versus floss debate rarely mentions the interdental brush, yet it is one of the tools with the best results. The Cochrane review concluded that it may be more effective than floss at reducing gingivitis (Worthington et al., 2019), and in the network meta-analysis it had the highest probability of ranking first (Kotsakis et al., 2018).
The catch is size. It has to fit snugly without forcing, and the right size changes from one space to another in the same mouth. A brush that is too thick damages the gum and one that is too thin does not clean, so it is worth having someone who has seen your spaces choose it for you.
At the clinic we recommend a water flosser to most of our patients. These are the situations where it makes the biggest difference:
The whole routine takes one or two minutes, and once a day, ideally at night, is the usual recommendation. Slight bleeding in the first few days is usually the same inflammation the water flosser helps reduce. The studies reviewed by Cochrane recorded no serious adverse events (Worthington et al., 2019). Plain water is enough for the reservoir; if you want to add a mouthwash, check with your dentist first (mouthwash: what it does and which one to choose explains how they differ).
Cut about 40 centimeters and wind it around your middle fingers, leaving a short section between your hands. Slide it through the contact point with a gentle back-and-forth motion, without snapping it into the gum. Then wrap it around the tooth in a C shape and move it up and down a couple of times, just under the gumline. Repeat on the neighboring tooth and use a clean section for each space. For braces, there are flosses with a stiff end and floss threaders that make it easier to pass under the wire.
Before or after brushing? In a clinical trial, flossing first and brushing afterwards removed more plaque between the teeth and left more fluoride in that area than the reverse order (Mazhari et al., 2018). It was a small study of 25 participants, but the logic holds: you clear the space first, and the fluoride toothpaste then reaches it better. There is no equivalent study for water flossers, although using one before brushing follows the same reasoning.
Neither a water flosser nor floss treats gum disease that is already established. See a dentist if you notice:
The right tool depends on your mouth, and we choose it by looking at it. During our Airflow dental cleaning we sometimes use a disclosing dye that shows where biofilm remains after your home routine, and we review those areas with you to adjust that routine. Reviews on oral hygiene agree that individually tailored instruction is the foundation of periodontal prevention (Sälzer et al., 2020).
If you decide to add a water flosser, several Waterpik models are available at our reception in Vitacura. And if you would like us to review your current routine, you can book an evaluation with us.
If this article left you with questions, explore the related services or book an evaluation at AS Odontología Digital in Vitacura.
Book an evaluationFor many people, yes, as the main way to clean between the teeth, especially if flossing never became a habit. In head-to-head comparisons the water flosser performs as well as or better than floss for gum health. The exception is very tight teeth that trap food at the contact point; there, floss is still useful. Neither replaces brushing.
Studies slightly favor the water flosser for reducing gum inflammation, and a meta-analysis ranked interdental brushes and water flossers above floss. The difference is not large and the evidence is short term. In practice, the best tool is the one that fits the spaces between your teeth and that you will use every day.
Yes. It cleans around brackets in less time than floss threaded under the wire. A meta-analysis in patients with fixed orthodontic appliances found no significant difference between water flosser and floss, so the choice mostly comes down to which one you find easier to keep up.
Used correctly, no. The trials reviewed by Cochrane recorded no serious adverse events. Start on the lowest pressure and increase it gradually. Slight bleeding in the first days is usually pre-existing inflammation; if it lasts more than two weeks, see your dentist.
Before. In a clinical trial, flossing first and brushing afterwards removed more plaque between the teeth and left more fluoride in that area than the reverse order. It was a small study, but the logic holds: you clear the space, and the fluoride toothpaste then reaches it better.
Once a day, ideally at night, is the usual recommendation. It takes one or two minutes. Consistency is what matters: a water flosser used every day does more than one used now and then.
For most people, lukewarm water is enough. Some mouthwashes can be used in a water flosser, but not all are suitable for daily use or for every device, so check with your dentist before adding one.
