Written and maintained by CASRAI Editorial Board
Last updated
Not medical advice. This guide describes dental floss as a product and summarizes what named public sources say about it. It does not replace advice from a dentist or orthodontist.
Short answer
Dental floss types differ mainly in fiber and coating. U.S. regulation defines floss as a string-like device made of cotton or other fibers, which may be coated with wax. The American Dental Association (ADA) says floss is usually made from nylon filaments or plastic monofilaments, and that waxed and unwaxed floss are equally effective. Dental tape is another name for the same kind of product.
What is dental floss?
Under 21 CFR 872.6390, dental floss is a string-like device made of cotton or other fibers intended to remove plaque and food particles. The regulation notes that the fibers may be coated with wax. In the United States it is a Class I device (general controls) that is exempt from premarket notification, subject to the limitations in 21 CFR 872.9. The ADA describes the same product as floss, or dental tape, used to clean between the teeth.
How does dental floss work?
The regulatory description is functional: a strand of fiber intended to remove plaque and food particles. The ADA and its MouthHealthy site describe a smooth strand of nylon or Teflon made to slide easily between teeth.
Dental floss material and coating
Three public sources name different materials, so no single “standard” material applies. The table keeps each statement attached to the source that makes it.
| Source | What it says about material or coating |
|---|---|
| 21 CFR 872.6390 (FDA classification regulation) | Made of cotton or other fibers; fibers may be coated with wax. |
| ADA oral health topic: Floss | Usually made from nylon filaments or plastic monofilaments; waxed and unwaxed floss are equally effective; rare cases of contact hypersensitivity to waxed or coated floss have been reported. |
| ADA MouthHealthy: Flossing | Standard floss is a smooth strand of nylon or Teflon made to slide easily between teeth. |
Waxed and unwaxed floss
The ADA states there is no difference in the effectiveness of waxed or unwaxed floss. Coating is therefore a product attribute, not an effectiveness claim. The same ADA page notes that rare cases of contact hypersensitivity to waxed or coated floss have been reported.
Floss, dental tape and other interdental tools
The ADA uses “dental floss (or dental tape)” for the same product. ADA MouthHealthy lists other tools for cleaning between teeth: dental picks, tiny brushes and water flossers.
Dental floss sizes
The FDA classification regulation sets no dimensional requirement, and the ADA pages cited here do not define floss sizes or thicknesses. A product’s own labeling is the place to find any dimension a manufacturer states.
Where it matters for supply decisions
- Regulatory status: floss is a Class I device exempt from premarket notification under 21 CFR 872.6390, so the absence of a 510(k) clearance is expected for this product type. The exemption is subject to 21 CFR 872.9.
- Material and coating are label facts: because the regulation allows cotton or other fibers and an optional wax coating, and the ADA names nylon and plastic monofilament, the material to record is whatever the manufacturer’s label states.
- Coating: the ADA notes that rare cases of contact hypersensitivity to waxed or coated floss have been reported, so the coating is a label attribute worth recording.
- Single use: the ADA does not recommend using devices to clean between the teeth more than once, so floss is a single-use consumable.
For related device background see what is a medical device, the FDA entry, and the Medical Device Amendments of 1976, which established the device classes. A neighboring single-use consumable is covered in what is a latex glove.
Common misunderstandings
Waxed floss is more effective
The ADA says there is no difference in effectiveness between waxed and unwaxed floss.
Floss is a drug or needs FDA clearance
It is a Class I device and exempt from premarket notification (21 CFR 872.6390), though not exempt from general controls.
All floss is nylon
Sources vary: the regulation says cotton or other fibers, the ADA says usually nylon filaments or plastic monofilaments, and MouthHealthy says nylon or Teflon.
FAQ
Can I reuse dental floss?
No. The ADA does not recommend using devices to clean between the teeth more than once, and notes that used floss can fray and reuse may return bacteria from previous use. It describes floss as a discard-after-use product.
What type of floss is recommended for braces?
The ADA and FDA sources cited here do not name a floss type for braces. A dentist or orthodontist can advise on the right tool for a given appliance.
Sources
- 21 CFR 872.6390 Dental floss, https://www.law.cornell.edu/cfr/text/21/872.6390, checked 2026-10-30.
- American Dental Association, Floss, https://www.ada.org/resources/ada-library/oral-health-topics/floss, checked 2026-10-30.
- ADA MouthHealthy, Flossing, https://www.mouthhealthy.org/all-topics-a-z/flossing, checked 2026-10-30.
