Written and maintained by CASRAI Editorial Board
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General product and regulatory information only, not medical or dental advice. Ask a dentist about what suits a particular mouth.
Short answer
An oral irrigator is a device that sends a pressurized stream of water between the teeth to remove food particles. The American Dental Association (ADA) calls the consumer version a water flosser. In US federal regulation the same product class is an “oral irrigation unit”: an AC-powered device, Class I (general controls) and exempt from premarket notification, subject to the limits in 21 CFR 872.9.
Definition and scope
The US federal regulation and the American Dental Association (ADA) describe this device in slightly different words, which matters when you search a catalogue or write a specification.
- FDA regulation (21 CFR 872.6510): “An oral irrigation unit is an AC-powered device intended to provide a pressurized stream of water to remove food particles from between the teeth and promote good periodontal (gum) condition.”
- ADA MouthHealthy: “A water flosser is a handheld device that sprays streams of water in steady pulses.” The water, like traditional floss, removes food from between teeth.
So “oral irrigator”, “oral irrigation unit” and “water flosser” point to the same family of dental hygiene devices. The regulation’s definition covers AC-powered units.
This is a dental hygiene device. It is not the same thing as the syringes and irrigation sets used to flush wounds or surgical sites; for that topic see wound and surgical irrigation supplies.
How it is described in practice
The ADA describes water flossing as a way to clean between and around the teeth, and places the water flosser in the “cleaning between your teeth” part of a dental hygiene routine. Operating instructions, settings and cleaning of the unit are set by the manufacturer, so follow the instructions for use supplied with the specific product.
Regulation versus ADA statements: what each source actually says
The table sets out, claim by claim, which source supports which statement, so neither is over-read.
| Question | FDA, 21 CFR 872.6510 | ADA MouthHealthy |
|---|---|---|
| What name is used? | “Oral irrigation unit” | “Water flosser” |
| What does it do? | Provides a pressurized stream of water to remove food particles from between the teeth | Sprays streams of water in steady pulses to remove food from between teeth |
| Power source | AC-powered | Describes it as handheld; does not state a power source |
| Gum condition | Intended to promote good periodontal (gum) condition | Not compared here |
| Plaque | Not mentioned | Only Seal-bearing products are described as tested to be safe and effective at removing plaque |
| Risk class | Class I (general controls); exempt from premarket notification subject to 21 CFR 872.9 | Not addressed |
| Replaces brushing or flossing? | Not addressed | Not stated; the page presents water flossing as one way to clean between teeth |
Types and related terms
Neither the regulation nor the ADA page defines device sub-types, so countertop versus handheld is not a regulatory category. What they do establish is the vocabulary:
- Oral irrigation unit: the term in 21 CFR 872.6510, the regulatory identification.
- Water flosser: the term the ADA uses on MouthHealthy.
- Oral irrigator: the common name used for both.
For a wider view of cleaning-between-teeth options, see dental floss types.
Where it matters for clinics and supply decisions
- Regulatory status. Under 21 CFR 872.6510 the device is Class I, which means general controls apply, and it is exempt from the premarket notification procedures in subpart E of part 807, subject to the limitations in 21 CFR 872.9. For how exemption differs from clearance and approval, see FDA device classification, 510(k) and PMA and the 510(k) premarket notification guide.
- Reading evidence claims. The ADA says only products that have earned the ADA Seal of Acceptance have been tested to be safe and effective at removing plaque. A product without the Seal is not covered by that statement. The ADA publishes a list of accepted water flossers on MouthHealthy.
- Matching terminology. A specification or catalogue may use “oral irrigator”, “oral irrigation unit” or “water flosser”; all three can refer to the same device family, so search under each.
Common misunderstandings
“A water flosser replaces brushing and flossing.”
The ADA page does not say this. It describes water flossing as one way to clean between and around the teeth.
“Every water flosser has been shown to remove plaque.”
The ADA’s statement applies to water flossers that have earned the ADA Seal of Acceptance. It does not cover products without the Seal.
“Exempt from premarket notification means unregulated.”
The regulation classifies the device as Class I, which is subject to general controls. The exemption concerns the premarket notification (510(k)) procedure, and it applies subject to the limitations in 21 CFR 872.9.
“It is the same as a surgical or wound irrigation set.”
It is not. The regulation covers a device intended to remove food particles from between the teeth and promote gum condition.
FAQ
What is an oral irrigator?
An oral irrigator is a device that provides a pressurized stream of water to remove food particles from between the teeth. FDA names the class “oral irrigation unit” in 21 CFR 872.6510, and the ADA calls the handheld consumer form a water flosser.
What is the difference between an oral irrigator and a water flosser?
The difference is the name: “oral irrigation unit” is the regulatory term and “water flosser” is the ADA’s term for a device that sprays water in steady pulses to clean between teeth.
Is an oral irrigator a regulated medical device in the US?
Yes. It is identified in 21 CFR 872.6510 as Class I (general controls), exempt from premarket notification subject to the limitations in 21 CFR 872.9. Text checked 2026-10-30.
Does the ADA Seal apply to every water flosser?
No. The ADA says the plaque statement applies to water flossers that have earned the ADA Seal of Acceptance, and it publishes a list of ADA-Accepted water flossers.
Sources
All sources checked 2026-10-30.
- Electronic Code of Federal Regulations, 21 CFR 872.6510, “Oral irrigation unit”: https://www.ecfr.gov/current/title-21/part-872/section-872.6510
- American Dental Association, MouthHealthy, “Water Flossers and Water Flossing”: https://www.mouthhealthy.org/en/az-topics/w/water-flossers
