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Brush twice daily with fluoride toothpaste and clean between your teeth

Brushing all tooth surfaces and the gum line twice a day with fluoride toothpaste, spitting rather than rinsing, and cleaning between the teeth once a day.

At a glance

  • Evidence: Fluoride toothpaste prevents caries on high- to moderate-certainty randomised evidence; brushing twice rather than once rests on weaker observational data.Dental caries from brushing with fluoride toothpaste · Moderate certainty · Randomized intervention
  • What’s uncertain: The strongest evidence tests fluoride toothpaste; the extra protection from twice-daily rather than once-daily brushing is less certain.
  • First step: Brush twice daily for about two minutes with adult fluoride toothpaste, including before bed; see the full guidance for concentrations.
  • Before you try it: Young children need age-appropriate toothpaste amounts and fluoride concentrations to limit fluorosis risk; follow dental guidance. All precautions
Read the full takeaway

Fluoride toothpaste

This is two habits with very different evidence, and they should not be sold together. Brushing with fluoride toothpaste prevents caries, and that is one of the better-established findings in prevention: a Cochrane review of 96 trials found high- and moderate-certainty evidence that toothpaste containing 1000 to 1250 ppm or 1450 to 1500 ppm fluoride reduces caries increments compared with non-fluoride toothpaste, and an earlier review of 74 trials in children put the prevented fraction at 24%. Brushing twice rather than once is supported by consistent observational evidence that the review's own authors call weak, and the widely repeated figure of a 14% lower caries risk comes from that observational base rather than from a trial.

Interdental cleaning

Cleaning between the teeth is a different story: the Cochrane review of 35 randomised trials found low-to-very-low-certainty evidence that floss or interdental brushes added to toothbrushing may reduce gingivitis or plaque, no trials that assessed interproximal caries at all, and effect sizes its own authors say may not be clinically important.

What flossing has not established

The single most important gap is that no trial has tested whether self-flossing prevents caries, and the only positive caries signal in the flossing literature comes from professionally applied flossing rather than from the habit a person does at home.

Whole-body health claims

What this habit is not is a route to whole-body health: no intervention trial has shown that toothbrushing, flossing or periodontal treatment prevents cardiovascular disease, and the current American Heart Association statement says a cause-and-effect relationship has not been confirmed and that there is no direct evidence that periodontal treatment will help prevent cardiovascular disease. Claims that oral hygiene prevents dementia or extends life rest on observational associations that no trial has tested, and the US preventive-services assessment of adult oral health explicitly found no evidence evaluating interventions against cardiovascular or cognitive outcomes.

A man brushing his teeth with an electric toothbrushDiscussed by2 peopleView statements ↓
Long-term healthUnder 10 min · Easy · Low
Reviewed Sep 24, 2026
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Scientific evidence

What the research shows

Outcome assessments based on research, including its uncertainties and limitations.

Dental caries from brushing with fluoride toothpaste

Finding: Benefit supportedCertainty: Moderatestudies found a benefit from doing this

Evidence basis: randomised trials

Fluoride toothpaste prevents caries on high- to moderate-certainty randomised evidence; brushing twice rather than once rests on weaker observational data.

Population: Children, adolescents and adults across 96 randomised trials published between 1955 and 2014 with at least one year of follow-up, including 48,804 randomised participants in the trials of toothpaste up to 2400 ppm in the immature permanent dentition and 2,162 evaluated participants in trials of up to 1100 ppm in the mature permanent dentition; and 33 observational studies of self-reported brushing frequency in the frequency meta-analysis. Most trials in the Cochrane review were conducted in populations with higher caries increments than contemporary high-income countries now have.

Research details

Summary

This is the best-evidenced part of the routine. A Cochrane review of 96 randomised trials found high- and moderate-certainty evidence that toothpaste containing 1000 to 1250 ppm fluoride (SMD -0.28, 95% CI -0.32 to -0.25; 55 studies) or 1450 to 1500 ppm (SMD -0.36, 95% CI -0.43 to -0.29; four studies) reduces caries increments compared with non-fluoride toothpaste, and moderate-certainty evidence that 1450 to 1500 ppm is slightly better than 1000 to 1250 ppm (SMD -0.08, 95% CI -0.14 to -0.01). Above 1500 ppm the dose-response is flat: caries increments were similar for 1700 to 2200 ppm and 2400 to 2800 ppm compared with 1450 to 1500 ppm (SMD 0.04, 95% CI -0.07 to 0.15, indirect evidence only; and SMD -0.05, 95% CI -0.14 to 0.05), so a higher-fluoride paste is not a general upgrade for adults without a specific indication. An earlier Cochrane review of 74 trials in children and adolescents found a pooled prevented fraction of 24% (95% CI 21% to 28%) for permanent teeth. Brushing frequency is the weaker component: a meta-analysis of 33 observational studies found higher odds of carious lesions in people who brushed less than twice a day (OR 1.45, 95% CI 1.21 to 1.74) than in those who brushed twice or more, but the exposure is self-reported and the authors state plainly that the evidence base for twice-daily brushing is weak. Adverse effects in these trials were assessed only by a minority of studies and were minimal when reported.

Why this certainty

Rated Moderate. Certainty is not lower because the intervention has been tested in 96 randomised trials with a dose-response gradient, the direction is consistent, and the review grades the two central comparisons as high and moderate certainty rather than low. It is not Strong because the outcome is a caries increment measured over one to three years rather than a clinical event, because the trials are old and were run in higher-caries populations, because the fluoride-versus-non-fluoride comparison does not test the frequency advice that most readers are actually asking about, and because adverse effects were assessed in only a minority of trials.

Limitations

The strongest evidence is about fluoride concentration, not about brushing as a behaviour: the comparison is fluoride toothpaste against non-fluoride toothpaste, so it does not tell a reader how much extra protection brushing twice rather than once provides. The twice-daily recommendation rests on observational data with a self-reported exposure. The 14% figure that is widely quoted for brushing twice rather than once comes from the UK toolkit's fluoride chapter, which attributes it to a meta-analysis of observational studies rather than to a randomised trial, so it is a citation of a recommendation and not itself trial evidence. Most of the trials are old and were run in populations with much higher caries rates, so the absolute benefit today is likely smaller even if the relative effect holds. Caries increment measured over one to three years is a surrogate count rather than a patient-centred outcome, and the trials rarely measured pain, extraction or how the teeth looked. Adverse effects were measured in a minority of studies, so the safety estimates are as thin as the efficacy estimates are strong. One further limit applies to the guidance rather than to the evidence: the toolkit is consensus guidance with graded recommendations, not a new synthesis, and it is now stored as a source with that stated so a reader can weigh it accordingly. The World Health Organization's summary of its 2020 physical-activity guidelines recommends regular muscle-strengthening activity and states that both aerobic and muscle-strengthening activity matter, but the specific twice-weekly wording belongs to the guidelines document itself, which no pass has retrieved, so it is not quoted here.

Effect estimate

Fluoride 1000-1250 ppm versus non-fluoride toothpaste: SMD -0.28 (95% CI -0.32 to -0.25; 55 studies). Fluoride 1450-1500 ppm versus non-fluoride: SMD -0.36 (95% CI -0.43 to -0.29; 4 studies). 1450-1500 ppm versus 1000-1250 ppm: SMD -0.08 (95% CI -0.14 to -0.01; 10 studies). 1700-2800 ppm versus 1450-1500 ppm: SMD 0.04 (95% CI -0.07 to 0.15, indirect) and SMD -0.05 (95% CI -0.14 to 0.05). Children and adolescents, permanent teeth: prevented fraction 24% (95% CI 21% to 28%). Brushing less than twice a day versus twice or more: OR 1.45 (95% CI 1.21 to 1.74), observational.

Sources for this outcome:

Gingivitis and plaque from cleaning between the teeth

Finding: Mixed evidenceCertainty: Very limitedstudies disagree, or the effect depends on who is studied

Evidence basis: randomised trials

Cleaning between the teeth is supported by low-to-very-low-certainty trial evidence for gingivitis and plaque, and no trial has tested it against caries at all.

Population: 3,929 randomised adult participants across 35 trials of at least four weeks in the interdental-cleaning review, most with a low level of baseline gingival inflammation; and 582 intervention plus 501 control participants across twelve randomised trials of flossing in the earlier review. Trials were short-term, so the outcomes are measured over weeks to a few months rather than years.

Research details

Summary

Interdental cleaning has been tested more than the flossing debate suggests, and the trials are weak. A Cochrane review of 35 randomised trials with 3,929 adults found low-certainty evidence that flossing in addition to toothbrushing reduces gingivitis at one month (SMD -0.58, 95% CI -1.12 to -0.04; eight trials, 585 participants), with inconsistent results for bleeding sites and plaque; interdental brushes reduced plaque with low-certainty evidence and gingivitis with very-low-certainty evidence; and oral irrigators reduced the gingival index at one month with very-low-certainty evidence but did not reduce bleeding sites or plaque at any time point. The review states that only two of the 35 trials were at low risk of bias, that blinding is impossible, that participants in most trials had little gingival inflammation to begin with, and that the effect sizes observed may not be clinically important. Its most important sentence is a gap: no trials assessed interproximal caries, and most did not assess periodontitis. The earlier Cochrane review of flossing reached the same conclusion on caries from the other direction - of twelve trials with 582 intervention and 501 control participants, seven at unclear and five at high risk of bias and none at low risk, all reported plaque and gingivitis and none reported caries, calculus, attachment loss or quality of life, and the authors state that no studies reported the effectiveness of flossing plus toothbrushing for preventing dental caries. The 2019 record under the same review number is a withdrawal rather than an update: it was withdrawn because it had been superseded by that broader interdental-cleaning review, and its abstract is identical to the 2011 version, so no new trials have been added to the flossing evidence since 2011.

Why this certainty

Rated Very limited and recorded as Mixed evidence. It is not Little/no effect, because the pooled trial results for gingivitis and plaque point in a consistent direction and the Cochrane authors conclude that interdental cleaning may reduce them more than toothbrushing alone. It is not Limited, because the review's own certainty rating for those outcomes is low to very low, only two of 35 trials were at low risk of bias, effect sizes may not be clinically important, the trials are short and enrolled people with little inflammation, and no trial measured caries at all. The entry therefore describes a plausible, low-certainty benefit for gum inflammation and an entirely unstudied effect on decay, and says both.

Limitations

The evidence cannot separate the device from the behaviour, and it does not reach the outcome that matters most. No trial in either review measured caries, so the effect of interdental cleaning on tooth decay is unknown rather than small - the UK guidance states plainly that there is no evidence to determine whether interdental cleaning aids reduce caries when compared with toothbrushing alone. Participants in most trials started with little gingival inflammation, which limits how much improvement was possible and makes a small effect harder to distinguish from noise. Follow-up is weeks to months, so nothing here establishes whether the effect persists. Only two trials were at low risk of bias and blinding is impossible, so expectancy inflates the self-reported and examiner-measured indices alike. The comparison between devices is weaker still: interdental brushes may be more effective than floss, but that rests on low-certainty evidence for gingivitis at one and three months with no difference in probing pocket depth, and a dedicated meta-analysis in orthodontic patients found oral irrigators did not outperform floss. The one consistently positive caries signal in this literature is for professional flossing five days a week, which is not a self-care habit.

Effect estimate

Floss plus toothbrushing versus toothbrushing alone, gingival index at one month: SMD -0.58 (95% CI -1.12 to -0.04; 8 trials, 585 participants; low certainty); bleeding sites and plaque inconsistent (very low certainty). Interdental brushes, plaque: SMD -1.07 (95% CI -1.51 to -0.63; 2 trials, 93 participants; low certainty). Oral irrigators, bleeding sites at one month: MD -0.00 (95% CI -0.07 to 0.06); plaque SMD -0.16 (95% CI -0.41 to 0.10), neither significant. Caries: no trials assessed interproximal caries.

Sources for this outcome:

What people say

Who discusses this?

Public statements, with positions specific to each source and topic. These views do not determine the scientific evidence assessment.

What the research shows ↑

Practical steps and precautions

How to try it

  1. Brush twice a day for about two minutes with a toothpaste containing 1350 to 1500 ppm fluoride, at least one of those times last thing before bed. That concentration and the twice-daily minimum are the UK public-health recommendation for adults; the toolkit also states that a child under six, who cannot control swallowing, can use at least 1000 ppm instead. Adults can use a manual or powered brush; powered brushes reduce plaque and gingivitis slightly more in trials, but the reviews say the clinical importance of that difference is unclear, so preference is a reasonable way to choose.
  2. Spit out the excess toothpaste and do not rinse with water afterwards. Rinsing washes away the fluoride the toothpaste leaves on the teeth; the caries evidence for this specific step is a secondary analysis and surrogate studies rather than a dedicated trial, but the recommendation is universal and the mechanism is direct.
  3. Clean between your teeth once a day, before brushing. Where the gaps allow, interdental brushes fit and are probably more effective than floss; where teeth are tight, use floss or tape. This is the part of the routine with the weakest evidence, and it is still worth doing for gum health even though it has never been shown to prevent caries.
  4. Children under 3 should use only a smear of toothpaste and children aged 3 to 6 a pea-sized amount, because swallowing toothpaste during tooth formation is what causes fluorosis. From 7 years up, use the adult concentration.

Precautions

  • Fluoride toothpaste above 1000 ppm in children under six increases the chance of dental fluorosis, which is usually mild and cosmetic; moderate-certainty evidence supports this, and the risk is managed by using the right amount for the child's age rather than by avoiding fluoride. The evidence on the amount used is much weaker than the evidence on concentration, so the smear and pea guidance rests on dose arithmetic and good practice rather than on trials showing that amount predicts fluorosis.
  • Use a soft-bristled brush and gentle pressure. Hard bristles produce more gingival lesions than soft ones, and aggressive scrubbing is associated with gum recession and wear at the neck of the tooth, although no study has established that brushing causes clinically significant recession and the two best syntheses both call that evidence inconclusive.
  • Waiting about 30 minutes to brush after acidic food or drink is widely repeated and was not supported for human enamel by the one meta-analysis retrieved: delayed and immediate brushing did not differ for human enamel, and delayed brushing alone did not prevent erosive wear. Do not use that advice as a substitute for fluoride toothpaste, which did reduce wear in the same analysis.
  • Bleeding when you clean between your teeth usually reflects inflammation at a site that was not being cleaned rather than damage from the cleaning. If it persists despite daily cleaning, see a dentist; persistent bleeding is a reason for assessment, not a reason to stop.

References

Fluoride toothpastes of different concentrations for preventing dental caries.

Walsh T, Worthington HV, Glenny AM, Marinho VC, Jeroncic A · The Cochrane database of systematic reviews · 2019

Cochrane systematic review with pairwise and network meta-analysis of randomised controlled trials with at least one year of follow-upVerified from abstract
Open original source

Fluoride toothpastes for preventing dental caries in children and adolescents.

Marinho VC, Higgins JP, Sheiham A, Logan S · The Cochrane database of systematic reviews · 2003

Cochrane systematic review and meta-analysis of randomised and quasi-randomised controlled trials with blind outcome assessmentVerified from abstract
Open original source

Effect of Toothbrushing Frequency on Incidence and Increment of Dental Caries: A Systematic Review and Meta-Analysis.

Kumar S, Tadakamadla J, Johnson NW · Journal of dental research · 2016

Systematic review and meta-analysis of observational studies with self-reported brushing frequency as the exposureVerified from abstract
Open original source

Home use of interdental cleaning devices, in addition to toothbrushing, for preventing and controlling periodontal diseases and dental caries.

Worthington HV, MacDonald L, Poklepovic Pericic T, Sambunjak D, Johnson TM, Imai P, Clarkson JE · The Cochrane database of systematic reviews · 2019

Cochrane systematic review and meta-analysis of randomised controlled trials of at least four weeksVerified from abstract
Open original source

Flossing for the management of periodontal diseases and dental caries in adults.

Sambunjak D, Nickerson JW, Poklepovic T, Johnson TM, Imai P, Tugwell P, Worthington HV · The Cochrane database of systematic reviews · 2011

Cochrane systematic review and meta-analysis of randomised controlled trials comparing toothbrushing and flossing with toothbrushing alone. The 2019 record under the same review number is the WITHDRAWN version CD008829.pub3; this record is the version that carries the findings.Verified from abstract
Open original source

Background and safety references

These support context and precautions; they are separate from assessed outcome sources.

Delivering better oral health: an evidence-based toolkit for prevention — Chapter 8: oral hygiene

Department of Health and Social Care and NHS England · Department of Health and Social Care and NHS England (GOV.UK) · 2014

Government reportPublic-health toolkit chapter: consensus guidance for dental teams with graded recommendations and a stated evidence base, rather than a new synthesis. Published 12 June 2014, last updated 10 September 2025; the chapter was retrieved from GOV.UK during this pass and every figure quoted below was read on that page. The toolkit points its recommendation on toothbrushing-with-fluoride at a meta-analysis of observational studies rather than at a randomised comparison, which is why the entry does not treat the 14% figure as trial evidence.Verified from full textBackground or safety reference
Open original source

Delivering better oral health: an evidence-based toolkit for prevention — Chapter 9: fluoride

Department of Health and Social Care and NHS England · Department of Health and Social Care and NHS England (GOV.UK) · 2014

Government reportPublic-health toolkit chapter on fluoride, retrieved from GOV.UK during this pass. It is where the widely repeated figure about brushing frequency actually appears, and it attributes that figure to a meta-analysis of observational studies rather than to a randomised trial — which is the distinction the `oral-hygiene` entry makes.Verified from full textBackground or safety reference
Open original source

Topical fluoride as a cause of dental fluorosis in children.

Wong MCM, Zhang R, Luo BW, Glenny AM, Worthington HV, Lo ECM · The Cochrane database of systematic reviews · 2024

Cochrane systematic review of randomised, quasi-randomised, cohort, case-control and cross-sectional studies with GRADE assessmentVerified from abstractBackground or safety reference
Open original source

Powered versus manual toothbrushing for oral health.

Yaacob M, Worthington HV, Deacon SA, Deery C, Walmsley AD, Robinson PG, Glenny AM · The Cochrane database of systematic reviews · 2014

Cochrane systematic review and meta-analysis of randomised controlled trialsVerified from abstractBackground or safety reference
Open original source

Does delayed toothbrushing after the consumption of erosive foodstuffs or beverages decrease erosive tooth wear? A systematic review and meta-analysis.

Hong DW, Lin XJ, Wiegand A, Yu H · Clinical oral investigations · 2020

Systematic review and meta-analysis of in situ and in vitro studiesVerified from abstractBackground or safety reference
Open original source

Periodontal therapy for primary or secondary prevention of cardiovascular disease in people with periodontitis.

Ye Z, Cao Y, Miao C, Liu W, Dong L, Lv Z, Iheozor-Ejiofor Z, Li C · The Cochrane database of systematic reviews · 2022

Cochrane systematic review of randomised controlled trialsVerified from abstractBackground or safety reference
Open original source

Periodontal Disease and Atherosclerotic Cardiovascular Disease: A Scientific Statement From the American Heart Association.

Tran AH, Zaidi AH, Bolger AF, Del Brutto OH, Hegde R, Patton LL, Rausch J, Zachariah JP, et al. · Circulation · 2026

GuidelineAmerican Heart Association scientific statement summarising the evidence on periodontal disease and atherosclerotic cardiovascular disease, including Mendelian randomisation studies, interventions targeting periodontal disease, and systemic markers. Facts are quoted from the retrieved abstract. The statement's own risk language - that a cause-and-effect relationship has not been confirmed and that there is no direct evidence that periodontal treatment prevents cardiovascular disease - is published by the Association in its public summary of the statement rather than in the indexed abstract, and was not verified against the paywalled manuscript; the `oral-hygiene` entry attributes that wording to the Association's public summary and not to the paper.Verified from abstractBackground or safety reference
Open original source

Screening and Preventive Interventions for Oral Health in Adults: US Preventive Services Task Force Recommendation Statement.

US Preventive Services Task Force, Barry MJ, Nicholson WK, Silverstein M, Chelmow D, Coker TR, Davis EM, Donahue KE, Jaén CR, Li L, Ogedegbe G, Pbert L, Rao G, Ruiz JM, Stevermer J, Tsevat J, Underwood SM, Wong JB · JAMA · 2023

GuidelineUS Preventive Services Task Force recommendation statement based on a commissioned systematic evidence review; both recommendations are graded I (insufficient evidence). Facts are quoted from the retrieved abstract. The statement that the review found no evidence evaluating nonoral health outcomes appears in the Task Force's published recommendation statement and evidence report, not in the indexed abstract, so it is not stored here as a quoted fact; the `oral-hygiene` entry attributes it to the Task Force's recommendation statement.Verified from abstractBackground or safety reference
Open original source

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Editorial history and review method

Revision 3 · Approved for publication · Codex (publication approval explicitly authorized by site owner; category migration)

Prepared and checked with AI. Publication approval does not imply independent expert review. Request a correction.

New entry, added at Standard coverage in the 2026-09-23 pass. It was in the expansion brief and in plan.md's merged list but absent from the canonical catalogue. The two behaviours are assessed separately because their evidence differs: `caries-prevention` is Benefit supported at Moderate certainty from 96 randomised trials of fluoride toothpaste concentrations plus the 24% prevented fraction in children, while `interdental-cleaning-and-gingivitis` is Mixed evidence at Very limited certainty because the Cochrane review of 35 trials rates its outcomes low to very low, only two trials were at low risk of bias, and no trial has assessed interproximal caries at all. The flossing record cited is CD008829.pub2, which carries the findings; the 2019 record under the same number is a withdrawal that was superseded by the interdental-cleaning review rather than an update, and the withdrawal reason was not retrievable in this pass, so the entry says only that it was superseded. Background references carry the fluorosis, powered-brush, erosion-timing and systemic-disease material, including the 2026 AHA statement and the USPSTF Grade I assessment, and the verdict uses them to refuse the cardiovascular and dementia claims explicitly. Second reviewer must check: (a) whether the withdrawal notice wording should be verified against the Cochrane Library before the entry describes the supersession; (b) whether the UK guidance figures (1350-1500 ppm for adults, the 14% figure for twice-daily brushing) should be cited from Delivering Better Oral Health directly, since that document was retrieved during this pass but is not stored as a source; (c) whether the entry should name dementia at all, given the retrieved evidence is only that no intervention trial has measured cognitive outcomes. Second source-repair round: the WHO physical-activity guidelines are cited for what their abstract states - that regular muscle-strengthening activity is recommended for all age groups and that both aerobic and muscle-strengthening activity matter - rather than for the specific twice-weekly recommendation wording, which belongs to the guidelines document and was not retrieved. The practical step that carried the twice-weekly figure now carries only the fluoride concentration and brushing guidance, and the limitations note records the distinction. The long-standing open question about this entry is closed. Delivering Better Oral Health is now stored as a source with the schema's new publisher and sourceType fields rather than being given an invented journal, and both chapters the entry relies on are attached as background references. Every numerical figure copied from the toolkit was re-checked against the retrieved pages: the 1350 to 1500 ppm adult concentration, the twice-daily minimum with last thing at night or before bed, the smear for under-threes and the pea-sized amount for three- to six-year-olds, the spit-don't-rinse instruction and the two-minute cleaning time are all confirmed verbatim in the oral-hygiene chapter. The 14% figure for twice-daily brushing is confirmed but is in the fluoride chapter, not the oral-hygiene one, and the toolkit attributes it to a meta-analysis of observational studies; the entry now says which chapter it comes from and what kind of evidence the toolkit cites for it, rather than attributing it to UK guidance as a whole. A second reviewer should check that quoting consensus guidance beside Cochrane reviews does not invite a reader to weight the two equally - the source row now carries a Government report label to make the difference visible - and should confirm the toolkit's own update history, since the chapters were last updated in September 2025 while the publication date displayed is 2014. Publication release 2026-10-04: site owner authorized a bounded AI audit and release of this exact revision. See docs/release-audit-2026-10-04.md for source-check findings and limits. No independent health-professional or peer review is claimed. Category migration 2026-10-04: removed the separate goals field; categories: Long-term health → Long-term health. Research assessments, sources, guidance, precautions, and evidence review dates are unchanged. This revision awaits publication approval; no new evidence review is claimed. Publication approval 2026-10-04: site owner explicitly accepted all current category-migration revisions for deployment and requested that remaining limitations be retained in docs/content-review-backlog.md. Approval applies to this exact content revision. No new evidence review, independent expert review, or clinical validation is claimed; existing precautions and disclosures remain in effect.