Official guidance emphasizes slightly different priorities
The NHS advises flossing before brushing. The American Dental Association says that, provided you floss thoroughly, making it a daily habit matters more than whether it comes before or after brushing. One recommends a sequence; the other emphasizes consistent practice.[1][2]
If you are starting a routine, “clean between the teeth, then finish with a toothbrush and fluoride toothpaste” is easy to follow. If you already floss reliably after brushing, you do not need to think that all your past efforts have been wasted.
What did the floss-first study actually measure?
A 2018 randomized crossover trial involving 25 dental students had each participant try both sequences. Flossing first produced greater reductions in interdental and overall plaque, and higher fluoride concentrations in interdental plaque. There was no significant difference in plaque at the gum margins.[3]
The experiment followed professional cleaning and a 48-hour pause in oral hygiene. That was a research condition, not a preparation to copy at home. The outcomes were short-term plaque and fluoride measurements, so they cannot establish that changing the order alone reduces decay or gum disease over many years.
Passing floss through a gap is not the same as cleaning a tooth
Floss is not only for removing food. It helps clean plaque—the bacterial film on teeth—from spaces that a toothbrush cannot fully reach. The NHS describes curving floss into a C shape against a tooth and moving it gently up and down.[1]
Pushing floss through the contact once and immediately pulling it out may not achieve that purpose. Avoid snapping it into the gum, and follow the surface of each tooth on both sides of a space. If it remains painful or difficult, ask your dental team to check your technique.[2]
Using floss does not reduce the need to brush
A 2019 Cochrane review assessed studies adding floss or other interdental devices to toothbrushing. Some measures of gum inflammation may improve, but the evidence was of low to very low certainty and mainly covered short periods. This review did not establish the best flossing sequence.[4]
Remember that floss and a toothbrush reach different areas. Flossing does not replace brushing, and following the “right” order does not prove that no surfaces were missed. Focus on the areas actually cleaned, rather than simply completing a list of tools.
Finish with a routine you can maintain
The NHS advises brushing twice daily with fluoride toothpaste, spitting out the excess, and avoiding an immediate water rinse. Focusing on flossing order should not distract from habits that help make good use of the fluoride in toothpaste.[1]
If tiredness makes you skip flossing at night, set aside time earlier in the routine or at another time of day. The American Dental Association also encourages choosing a time that works for you. Learning the technique and repeating it daily is more practical than starting with an elaborate ritual you cannot sustain.[2]
Research and institutional sources
- NHS. How to keep your teeth clean. Last reviewed 30 June 2025.View source ↗Guidance on flossing first, flossing technique, and care after brushing with fluoride toothpaste.
- American Dental Association, MouthHealthy. Flossing.View source ↗Emphasizes thorough daily interdental cleaning over the order of brushing and flossing, and explains safe technique.
- Mazhari F, Boskabady M, Moeintaghavi A, Habibi A. The effect of toothbrushing and flossing sequence on interdental plaque reduction and fluoride retention: A randomized controlled clinical trial. Journal of Periodontology. 2018;89(7):824–832. doi:10.1002/JPER.17-0149. PMID:29741239.View source ↗A short-term crossover trial in 25 dental students measuring plaque and fluoride, not long-term disease prevention.
- Worthington HV, MacDonald L, Poklepovic Pericic T, et al. Home use of interdental cleaning devices, in addition to toothbrushing, for preventing and controlling periodontal diseases and dental caries. Cochrane Database of Systematic Reviews. 2019;(4):CD012018. doi:10.1002/14651858.CD012018.pub2.View source ↗A review of the added effects of interdental devices and evidence limitations; it does not settle the order of flossing.
Bracketed numbers in the text link to these sources. This article provides general health information; individual diagnosis and treatment plans are determined after a clinical consultation.
