Water flossers can be a useful way to clean between teeth, but research does not show that they universally replace string floss or that either method is best for everyone.
The two tools work differently. String floss makes direct contact with the sides of the teeth. A water flosser directs a stream of water around the gumline and between teeth. What matters in practice is choosing a suitable tool, using it carefully, and cleaning between the teeth consistently.
The short comparison
| Question | Water flosser | String floss |
|---|---|---|
| How does it clean? | Uses a controlled stream of water | Uses a strand to wipe against tooth surfaces |
| What may make it practical? | Some people find the handle and water stream easier to manage | It is portable, quiet, and needs no power or reservoir |
| Where can technique be challenging? | The tip still needs to be guided around the gumline and between teeth | The strand needs to pass the contact and curve against both teeth |
| Is it proven better for everyone? | No | No |
This is a comparison of cleaning approaches, not a product recommendation. Devices, floss types, tooth spacing, dental work, technique, and consistency can all affect the experience.
Why “as good as” is not one simple measurement
Studies do not all measure the same outcome. Some look at plaque immediately after one use. Others measure gum inflammation or bleeding over several weeks. A tool can perform similarly for one outcome and differently for another.
The broad 2019 Cochrane review found limited and inconsistent evidence for oral irrigators. In direct comparisons with floss, oral irrigation may have improved some short-term measures of gingivitis, while the evidence did not show a clear plaque difference. The certainty was low to very low, most studies were short, and long-term outcomes such as cavities between teeth and periodontitis were not adequately studied.
A newer systematic review found small possible benefits for some bleeding and gum-inflammation measures at certain time points. Plaque results were inconsistent, and certainty ranged from very low to moderate depending on the outcome and time point. These findings support water flossers as a reasonable option for some people, not as a universal upgrade.
What individual studies add—and what they cannot prove
Some head-to-head clinical studies report that a water flosser and string floss remove similar amounts of plaque. For example, a 2021 split-mouth study found no significant difference in plaque scores after a single professionally performed use. The two sides had different average plaque scores before cleaning, which limits how confidently that after-use result can be interpreted.
That result has important limits. A single supervised cleaning does not show how well either tool works over months or years at home. It also cannot establish which method prevents cavities, treats gum disease, or will be easiest for a particular person to use consistently.
Taken together, the research suggests that water flossers can contribute to between-teeth care. It does not support a promise that every water flosser matches every flossing technique for every health outcome.
When a water flosser may feel more manageable
Some people consider a water flosser because handling string floss is difficult. A powered device may be easier to hold or guide for someone who struggles to control a thin strand.
Water flossers may also seem practical around braces, bridges, or other dental work. Those situations are not all alike, however. The right tip, pressure, and path can depend on the appliance or restoration. A dentist or dental hygienist can demonstrate how to clean a specific area without assuming that one device is appropriate everywhere.
If you want a basic explanation before comparing options, see What Is a Water Flosser?.
When string floss may still fit well
String floss can work well in tight contacts because the strand can slide between teeth and curve around each tooth surface. It is also simple to carry and does not require charging, a reservoir, or sink cleanup.
Good technique matters. Guide floss between the teeth with a gentle rubbing motion rather than snapping it into the gums, then curve it around each tooth. How to Floss Properly explains the C-shape technique.
Cleaning between teeth should not keep causing pain. If it does, ask a dental professional to check the area and show an approach that fits.
A practical way to choose
Instead of looking for one winner, consider a few practical questions:
- Can you guide the tool around every area you need to clean?
- Can you use it without pain or forcing it into the gums?
- Does dental work or orthodontic hardware change the technique you need?
- Is the routine realistic enough to repeat consistently?
- Has your dental team recommended a specific method for a particular area?
Cost, storage, noise, access to an outlet or charging, water splash, and travel can matter too. These are convenience factors, not proof that a device will produce a better health outcome.
Look for clear manufacturer directions. A product-specific claim or an ADA Seal applies to the evaluated product; it does not prove that every device in the category works the same way.
Do you have to choose only one?
Not necessarily. “Clean between your teeth” is a goal, not a requirement to stay loyal to one tool in every space. Some people may use different approaches in different areas after a dental professional has shown them what fits.
Do not assume that using more tools or higher water pressure automatically cleans better. A routine should remain comfortable and purposeful. If your dental team has given instructions for braces, implants, bridges, gum problems, or recent dental work, follow those instructions over a general comparison.
For the separate question of routine frequency, see How Often Should You Floss?.
When to ask a dentist or hygienist
Ask for guidance if you are unsure how to clean around dental work or braces, cannot reach an area, or keep having pain, swelling, or persistent bleeding.
A dental professional can examine the area and demonstrate a technique. A water flosser or a piece of floss cannot diagnose why a spot bleeds or hurts, and changing devices is not a substitute for evaluating an ongoing concern.
The bottom line
Water flossers and string floss are both ways to support cleaning between teeth, but they do not work identically. Evidence suggests that water flossers may help with some short-term gum-health measures and may be easier for some people to use. The research remains too limited and inconsistent to name one universal winner.
The better practical choice is a suitable method you can use carefully and consistently, with individual guidance when tooth spacing, dental work, braces, symptoms, or technique make the choice less straightforward.
Sources
- Dental Floss/Interdental Cleaners — American Dental Association
- Flossing — MouthHealthy, American Dental Association
- Home use of interdental cleaning devices, in addition to toothbrushing, for preventing and controlling periodontal diseases and dental caries — Cochrane Database of Systematic Reviews (PubMed record)
- Alleviation of Plaque and Gingivitis with Dental Water Jet in Regular and Orthodontic Patients: A Systematic Review and Meta-Analysis — Healthcare (PubMed record)
- Comparison between water flosser and regular floss in the efficacy of plaque removal in patients after single use — The Saudi Dental Journal (PubMed record)