Oral care: what the official guidance says

Four questions about teeth have written answers from national bodies: how often to brush and for how long, how much fluoride a toothpaste may carry, whether a water flosser stands in for floss, and how often teeth are cleaned professionally. The answers differ between China, the United States and the United Kingdom, and on one question inside China.

Each answer below carries its issuing body, document and year; none is a plan for a particular mouth.

Brushing: frequency and duration

China’s national resident guide, published by the health ministry in 2009, puts the floor at two sessions: 每天至少要刷牙两次，晚上睡前刷牙更重要 — at least twice a day, the brush before sleep named as the more important one. It gives no duration, and puts the adult quantity at about 1 gram of paste (中国居民口腔健康指南, 发布 2009-09-15).

The Chinese Stomatological Association gives the duration: 每次刷牙时间不少于2分钟 (中华口腔医学会, 刊登于《健康世界》2019年3月总第304期). A core-message sheet for the September 2026 national dental health day repeats it and adds a new brush every three months (2026 年全国爱牙日重点人群口腔健康核心信息, 2026-09, hosted by the China CDC chronic-disease centre).

The multidisciplinary consensus on periodontal health in 中华口腔医学杂志 sets its patient-education content at 刷牙时间，2~3次/d，3 min/次 — two to three sessions a day, three minutes each, written for patients in periodontal maintenance after treatment (共识, 中华口腔医学杂志 2021, 56(2): 127-135).

Outside China the numbers sit close. The American Dental Association writes: “The consensus recommendation is for people to brush their teeth for two minutes twice a day with a toothbrush that has soft bristles,” and puts brush replacement at three to four months (ADA, Toothbrushes, page updated 2026-08). Its one-page patient sheet gives the same figures (ADA home oral care, PDF, 2024-07-22). The NHS page on keeping teeth clean writes twice a day for about two minutes, at night and on one other occasion (NHS, reviewed 2025-06-30).

The fourth national oral health survey, whose results the ministry released on 2017-09-19, put the adult twice-a-day brushing rate at 36.1 percent for the 2016 baseline (健康口腔行动方案 2019—2025 指标表, 国卫办疾控函〔2019〕118号, 2019-01-31; reported from the 2017 release by 新华网, 2017-11-04; see the last section).

Fluoride toothpaste: the concentration each body names

China regulates a band, not a target. The toothpaste filing rules set total fluoride at no more than 0.15 percent, with 含氟牙膏 at 0.05 to 0.15 percent and 儿童含氟牙膏 at 0.05 to 0.11 percent; below 0.05 percent a product may not be labelled a fluoride toothpaste. That is 500 to 1,500 ppm for adults and 500 to 1,100 for children, on my arithmetic at 10,000 ppm to the percent (国家药监局公告 2023年第148号, 附件3, published 2023-11-22, in force 2023-12-01). The stomatological association gives the same band and calls it the national standard: 我国国家标准含氟牙膏中氟含量在500～1500ppm，儿童含氟牙膏中氟含量500～1100ppm之间 (中华口腔医学会, undated page).

The British figure is a floor: adults need a toothpaste containing at least 1,350 parts per million (ppm) fluoride, children of all ages can use a family toothpaste holding 1,350 to 1,500 ppm, and children aged three and under without decay may use a children’s paste with at least 1,000 ppm (NHS, reviewed 2025-06-30).

The American association publishes no adult concentration. Its home-care review describes over-the-counter products as the 1,000-1,500 ppm range and prescription paste at 5,000 ppm, and its toothpaste page states that anything carrying the ADA Seal for cavity protection must contain fluoride (ADA, Home Oral Care; ADA, Toothpastes, read 2026-10-12).

The two ranges meet at an awkward angle: China’s children’s band stops at 1,100 ppm, while the NHS writes that children of any age can use a family paste at 1,350 to 1,500 ppm. Both are current.

The evidence behind the numbers is a Cochrane review of 96 randomised trials. It found high- and moderate-certainty evidence that 1,000 to 1,250 ppm and 1,450 to 1,500 ppm toothpastes reduce caries increments against non-fluoride paste, and concluded: “For many comparisons of different concentrations the caries-preventive effects and our confidence in these effect estimates are uncertain and could be challenged by further research” (Walsh et al., Cochrane 2019, 2019-03-04).

Floss, interdental brushes and water flossers

Position one: floss or an interdental brush, with the water-flosser evidence called limited. The 2009 ministry guide names 牙线 or 牙间刷 for the spaces between teeth, and puts a water flosser only in its chapter for people with disabilities. The association’s 2024 core messages write 除刷牙外，每天应使用牙线或牙间隙刷清洁牙齿缝隙, and the 2026 CDC sheet repeats it, naming a water flosser only for implants and fixed dentures. The NHS writes to floss or use an interdental brush every day (NHS, Take care of your teeth and gums, reviewed 2025-02-17), and the ADA topic page, updated August 2026, recommends cleaning between the teeth once a day with floss or another interdental cleaner (2024 core messages, PDF, 2024; 2026 core messages, PDF, 2026-09; ADA, updated 2026-08).

The evidence those pages cite is one review. A Cochrane review of 35 randomised trials with 3,929 adults concluded that “Using floss or interdental brushes in addition to toothbrushing may reduce gingivitis or plaque, or both, more than toothbrushing alone. Interdental brushes may be more effective than floss.” It described the evidence for cleaning sticks and oral irrigators as limited and inconsistent, reporting a gingivitis reduction at one month on very-low-certainty evidence and none at three or six months, and wrote that the effect sizes observed “may not be clinically important”. No included trial measured caries between the teeth (Worthington et al., Cochrane 2019, 2019-04-10). An earlier review of flossing alone found some evidence of a gingivitis reduction and called the plaque evidence “weak, very unreliable” (Sambunjak et al., Cochrane 2011, 2011-12-07); its 2019 update was withdrawn before publication.

Position two: a water flosser named as one of the tools. The association’s 2019 article writes 牙间隙的清洁通常使用牙线，间隙宽的可用牙缝刷，冲牙器也能有效清除牙间隙的菌斑 — interdental cleaning usually uses floss, a wide gap can take an interdental brush, and a water flosser can also effectively clear interdental plaque (中华口腔医学会, 2019-03). A draft group standard from the same association, on patients with reduced saliva, puts a water flosser alongside floss and grades it 证据等级：极低，推荐强度：强推荐 — very low evidence, strong recommendation (draft consensus, PDF, 2024, T/CHSA, for comment). In the United States the ADA runs a Seal category for powered interdental cleaners and oral irrigators, whose packaging statements read “Helps remove plaque (between teeth)” and “Helps prevent or reduce gingivitis (between teeth)” (ADA Seal requirements, revised 2026-08).

One named trial: a four-week randomised trial with 105 participants in the Journal of Dental Hygiene in 2023 compared a water flosser, a water flosser with air microbubbles, and floss, each with a manual toothbrush, and the water-flosser group showed the largest reductions in bleeding on probing, gingival inflammation and plaque. The disclosure states that one author was a Water Pik employee during the study (Journal of Dental Hygiene 97(5), 2023).

None of the documents I read states that a water flosser replaces floss, and none forbids it. I am not settling the question.

How often teeth are cleaned professionally

China’s written numbers are fixed, and not identical. The 2009 ministry guide writes 每年至少进行一次口腔健康检查 for the general population and 提倡每年洁牙（洗牙）一次 for professional scaling, adding 最好每年一次 — the guide’s stated preference is once a year. Its chapter for older people is tighter (指南, 2009-09-15). The association’s 2024 core messages put scaling at 每年1～2次, and the 2026 CDC sheet writes one to two examinations a year (2024 core messages, PDF, 2024; 2026 core messages, PDF, 2026-09).

Britain sets a range. NICE guidance CG19 says the interval before the next oral health review is chosen for each patient on assessed disease levels and risk, with a shortest interval of three months and a longest of 12 months under 18 and 24 months for adults (NICE CG19, published 2004-10-27, last reviewed 2020-03-31). The NHS check-up page, reviewed 2025-04-01, tells the patient the next visit can be from three months to two years (NHS, reviewed 2025-04-01).

The American position is delegation: its home-care review writes “See your dentist regularly for prevention and treatment of oral disease” and reports that a systematic review “failed to arrive at consensus regarding optimal recall frequency” (ADA, Home Oral Care, read 2026-10-12).

A Cochrane review published 2020-10-14 pooled two trials with 1,736 participants and concluded that for adults “there is little to no difference between risk-based and 6-month recall intervals” in caries, gingival bleeding and oral-health-related quality of life over four years, on high-certainty evidence; for children it called the evidence uncertain (Fee et al., Cochrane 2020, 2020-10-14).

Where these numbers come from

Every figure comes from a document I read on 2026-10-12, kept in the unit and wording of its source.

• Sources. Chinese documents from the publisher’s page or PDF; English ones from the bodies’ pages, with the “last reviewed” or “last updated” date each carries. Cochrane conclusions from the PubMed abstracts.
• The ppm conversions are mine. One percent is 10,000 ppm, so 0.05 percent is 500, 0.11 percent is 1,100 and 0.15 percent is 1,500. The documents give percentages.
• Access. The commission’s guide page and the drug regulator’s announcement page both returned HTTP 412 to my connection; those two were read through a different fetch path. The filing-rules annex is a .docx, read in full.
• Rechecking. The association’s 2019 article and the 2026 CDC sheet agree on two minutes and the daily interdental line; the ministry guide and the 2024 core messages differ on scaling, once a year against once or twice, and both appear above as written. No figure comes from a news story or a product listing.

What I could not check

• Whether any Chinese document declares a water flosser a replacement for floss. The ones I read list it as a tool among several or as an addition — a claim about the documents I could open.
• The status of the reduced-saliva consensus. I read a 征求意见稿, issued for public comment in 2024; it may since have been published in final form.
• The 2017 survey percentage on its release page. The ministry’s 2017-09-19 release gives the direction of the trend — twice-daily brushing “仍有较大提升空间” — without the 36.1 percent figure; I took the number from the same ministry’s 2019 action plan, which lists it as the 2016 baseline, and from the Xinhua report of the release.
• The ADA’s statement that recall intervals are “determined by a dentist”. It circulates in a 2013 ADA release as republished by third-party dental press; the ADA’s current page gives different wording, and I could not open an ada.org copy.
• Any national US interval for professional cleaning. Nothing I read states one.
• Trial-level detail behind the reviews. I read the reviews, not the individual trials. Who funded the irrigator trials in the 2019 review is not something I checked.