What can I do to strengthen my teeth?

Three things do almost all of the work: remove plaque thoroughly twice a day, expose the enamel to fluoride regularly, and reduce how often you consume sugar and acid. Everything else — diet supplements, whitening toothpastes, “enamel-building” marketing claims — is secondary to those three, and none of it compensates for getting them wrong.

The important thing to understand first is that “strengthening” has a hard limit. Enamel contains no living cells and cannot regrow. What it can do is re-mineralise — reabsorb calcium, phosphate and fluoride into a partly demineralised surface. That works on early, sub-surface mineral loss. It does not work once a cavity has formed, and it does not work on enamel that has been physically dissolved away by acid. Those two distinctions govern everything below. If enamel is the hardest substance in the body, why do teeth break? is the companion piece on why hardness is not the same as toughness.

How teeth get weakened

Dental decay

Decay is the most common consequence of weakened tooth structure. It is the result of interactions between dental plaque and the tooth surface. Plaque is the soft, furry film that develops on teeth after meals; the bacteria within it are fuelled by dietary sugars, and as they metabolise those sugars they produce acid. That acid leaches minerals out of the enamel. Repeated often enough and long enough, the mineral loss progresses to a physical hole. How does tooth decay develop? and the stages of dental decay follow that sequence through; how do I prevent dental decay? is the short version of what stops it.

The key point patients miss: it is the bacteria in plaque that make the acid, not the sugar itself. Sugar with no plaque does relatively little. Plaque with no sugar does relatively little. It is the combination, repeated frequently, that causes cavities.

The first visible sign is a chalky white mark rather than a hole — what causes white spots on teeth? — and that is the only stage at which the process can still be turned around: can you reverse tooth decay, and do I need a filling? and why do I need a filling?.

Enamel erosion

Erosion is different in mechanism and different in management. It is the result of prolonged direct acid contact — no bacteria involved. Acidic foods and drinks are the usual culprit; so is reflux, and so is frequent vomiting. See what is dental erosion and how is it addressed? and I’ve heard a lot about acid wear — what is this and how can I avoid it?.

Erosion is a complex condition to treat, and if allowed to progress it causes significant sensitivity and discomfort — what to do if you suffer from sensitive teeth. Critically, eroded enamel is gone permanently. Fluoride can harden what remains and reduce further loss, but it cannot rebuild lost thickness. This is why erosion is worth catching early: the cheap intervention is behavioural, and the expensive intervention is restorative — compare the two in the price guide.

The two compared

A third mechanism sits alongside both and is often the one doing the visible damage: wear from grinding and clenching. See night time tooth grinding and clenching, what is bruxism and how is it managed? and TMD and teeth grinding. Grinding on enamel already softened by acid does far more damage than either alone.

Oral hygiene

Keeping plaque at bay is the foundation. Plaque accumulates quickly after meals and needs to be removed regularly, before the bacteria within it can damage the tooth. If plaque is not disrupted, minerals are leached from the enamel and a cavity eventually follows. What is the ideal daily routine for oral hygiene? and three oral hygiene tips you need to know set out the whole routine.

• Brush thoroughly twice daily. Thoroughly is doing the work in that sentence — two minutes, every surface, including the gumline where plaque is thickest and the last molars where the brush rarely reaches. See how often should I brush my teeth?, how much pressure should I apply when brushing my teeth? and which toothbrushes do dentists recommend?. More pressure is not more cleaning: over brushing: what can it do to my teeth?.
• Clean between the teeth once daily, with floss or interdental brushes. Around a third of each tooth’s surface is between the teeth and is never touched by a toothbrush; that is exactly where adult decay most often starts — is flossing really that important?.
• Timing after acid matters. After anything acidic — citrus, wine, soft drink, sports drink, or vomiting — wait about an hour before brushing. Enamel is temporarily softened, and brushing immediately scrubs away the softened layer. Rinse with water in the meantime. Brushing your teeth: before or after breakfast? is the same question in its most common form.

What a brush cannot remove, a hygienist can: what does a dental hygienist do?, your Smile Solutions dental hygienist visit: what to expect and, where the gums have already been affected, when do you need deeper cleaning?.

Fluoride

Of all minerals, fluoride is the most important for re-strengthening enamel. When the mouth is exposed to fluoride, the enamel absorbs it and replaces minerals lost during the day. It does more than replenish, though: the fluoride that incorporates into the enamel surface forms a mineral that is more acid-resistant than the original, so it also protects against future loss. The benefits of fluoride covers the mechanism in more detail.

How to actually get the benefit:

• Brush twice daily with a fluoridated toothpaste. Standard adult toothpastes contain 1,000–1,500 ppm fluoride. On choosing one: selecting a toothpaste — fluoride or non-fluoride?, choosing the right toothpaste, choosing the right toothpaste for you and with so many toothpastes on the market, how can I make a wise choice?.
• Spit, don’t rinse. Rinsing with water immediately after brushing washes away the fluoride before it can act. This single change costs nothing and is one of the highest-value habits in dentistry. The same applies to mouthwash used straight after brushing — should I be using mouthwash as well as brushing and flossing my teeth? and the truth and myths about mouthwashes.
• Higher-concentration options exist for higher-risk patients. If you are at increased risk of mineral loss, your dental professional may prescribe additional products — high-fluoride toothpastes, topical crèmes containing calcium and phosphate, or fluoride mouth rinses. These are recommended on assessment, not bought speculatively.
• Melbourne’s water supply is fluoridated, which provides a low-level constant background exposure. That is a floor, not a substitute for topical fluoride from toothpaste. Both sides of that debate are put in fluoridated water — is it good for you? and fluoridated water: why I worry.

For teeth with deep grooves, sealing them is a mechanical rather than chemical defence: who is a suitable candidate for dental sealants? and the role of fissure sealants in children’s teeth.

Dietary choices

The strength of your teeth is directly related to what you eat and drink — how does your diet affect your teeth? and six foods to avoid for healthy teeth.

Sugar and decay. Plaque bacteria thrive on sugar as their major food source, so the more sugar consumed, the higher the risk of a cavity. When bacteria metabolise sugars, the minerals that give the tooth its strength are dissolved out. See how does sugar affect your dental health? and sugar: what does it do to your teeth?.

The refinement worth knowing: frequency matters more than quantity. Each sugar exposure triggers an acid attack lasting roughly 20–40 minutes before saliva restores the pH. A dessert eaten in ten minutes is one attack. The same amount of sugar sipped from a bottle across an afternoon is a continuous one. Six sweetened coffees a day is a worse decay risk than a single large slice of cake.

Acid and erosion. Citric and acidic foods and drinks can irreversibly wear away enamel, causing erosion and associated sensitivity — how does acidic food affect your teeth?. Common offenders that people do not think of as “acidic”: sparkling water with citrus — is soda water bad for your teeth? — kombucha, cider, sports drinks — what are sports drinks really doing to your teeth? — sugar-free soft drinks, where the acid rather than the sugar does the damage — are sugar free soft drinks better for my teeth than regular soft drinks? — and slices of lemon in water throughout the day. Wine belongs on the list too: what impact does wine have on my teeth?.

Practical mitigations that do not require giving anything up:

• Keep acidic and sugary items to mealtimes rather than grazing.
• Drink acidic drinks reasonably quickly, and through a straw where practical, rather than sipping over an hour.
• Follow with water, or finish with something that raises pH — cheese, milk, plain nuts.
• Chew sugar-free gum after meals. It stimulates saliva, which is the body’s own re-mineralising fluid; gum containing xylitol has additional evidence behind it — does chewing sugar-free gum really help prevent cavities?.

Saliva is doing more than you think

Saliva buffers acid, washes away debris, and carries the calcium and phosphate that re-mineralisation depends on. Anything that reduces saliva therefore weakens teeth directly:

• Medications — antidepressants, antihistamines, blood-pressure medications, diuretics and many others cause dry mouth. See my mouth is always dry — why is this and does it affect my teeth? and my mouth always feels dry! What can I do?.
• Mouth breathing and snoring — dries the upper front teeth in particular. Mouth breathing: the silent habit that’s changing your face and your health and snoring and sleep apnoea.
• Dehydration, alcohol, some medical conditions and head/neck radiotherapy. If you exercise, what causes dry mouth during running? and how exercise can increase your risk of tooth decay apply.

If you have a dry mouth, your decay risk is elevated regardless of how well you brush, and it needs to be managed actively — shorter recall intervals, high-fluoride products, saliva substitutes. Tell your dentist about every medication you take; it changes the assessment. Diabetes changes it as well, in both directions: diabetes and dental health: the two-way street that most people don’t know about.

What to do if you are already noticing a problem

If you are concerned about weakened teeth, suspect you may have a cavity, or are experiencing sensitivity, get it assessed rather than self-treating. Sensitivity in particular has several very different causes — erosion, recession, a cracked tooth, a failing filling, decay, grinding — and the correct treatment for one is useless for another. See why does a cracked tooth hurt so much? and how will my cracked tooth be treated?. A thorough assessment establishes the cause, and the cause determines whether the fix is a change of habit, a fluoride programme, or a restoration. Understanding your treatment describes what a full assessment covers, and how often should I go to the dentist? how frequently it should happen.

Common questions

Do "enamel repair" and "remineralising" toothpastes do anything, or is it marketing?

The claim that has independent backing is the one on the back of the tube, not the one on the front. The World Health Organization names "inadequate exposure to fluoride" alongside high free-sugar intake and poor plaque removal as what allows decay to develop, and specifies brushing "with fluoride toothpaste containing 1000-1500 ppm concentration". That concentration is the single specification worth checking, and it is printed in the ingredients panel.

What the fluoride is doing is genuinely repair-like, and the NHMRC describes it as three separate effects rather than one: it reduces demineralisation, "enhanc[es] remineralisation (i.e. recovery of weakened enamel)" which "helps the repair of early tooth decay", and it slows the activity of the bacteria that cause decay, combining with the enamel surface "to make it stronger and better able to resist decay".

What no toothpaste can do is rebuild enamel that has been physically lost, or fill a cavity that has formed. That limit is set by the tissue, not by the product — as the top of this page says, enamel has no living cells.

Two habits beat any upgrade in product. Research on fluoride and caries prevention records "a 14% reduction in caries increment when moving from once- to twice-daily brushing". And not rinsing the toothpaste away matters: the same literature found that "rinsing with a non-fluoride mouth rinse soon after brushing with standard fluoride toothpaste may reduce the anticaries protection provided by brushing with a fluoride toothpaste alone", while a rinse containing at least 100 ppm fluoride did not. Frequency and retention, then concentration. The branding is last.

Should I take calcium tablets or fluoride supplements to strengthen my teeth?

Fluoride supplements are not something to start on your own. The NHMRC's position is explicit: "Fluoride supplements in the form of drops or tablets should only be used on the advice of an oral health professional", adding that "they are no longer readily available in Australia". The reason is dose: fluoride's benefit at the tooth surface is topical and small, while swallowed fluoride during the years teeth are forming is what causes fluorosis.

On calcium, the Australian Dental Association's dietary position is about food rather than tablets: "Calcium rich foods and drinks such as milk, cheese and some fish should be promoted as the preferred source of dietary calcium." That also happens to be useful at the end of a meal, because those foods are not acidic.

Where supplements actively backfire. The ADA notes that "medications, including over-the-counter vitamin and mineral tablets, may include sugars (particularly those that are chewable and dissolved in the mouth) or contribute to dry mouth, both of which can contribute to tooth decay or softening and loss of tooth structure", and it lists "chewing and sucking acidic vitamin tablets" among the habits to avoid for anyone at risk of decay or erosion. A daily chewable vitamin C can be doing more damage than the diet it is supposed to correct.

The honest hierarchy for strengthening teeth is the one at the top of this page: plaque removal, topical fluoride, and the frequency of sugar and acid. A supplement aisle does not contain a shortcut past it. If your risk is genuinely high — dry mouth, a heavy decay history, an eating disorder or reflux — that is a reason to be assessed for prescribed products, not to self-select.

Is fluoridated water actually safe? I have read the arguments against it.

The Australian position is set by the NHMRC, and it is unambiguous — which is worth reading in its own words rather than anyone's summary. After a comprehensive review of research published between 2006 and 2015, its conclusion is that "the existing body of evidence consistently shows that water fluoridation safely reduces tooth decay", and its public statement is that "NHMRC strongly recommends community water fluoridation as a safe, effective and ethical way to help reduce tooth decay across the population".

On the objection people raise most often — fluorosis — the detail is more interesting than either side usually admits. The NHMRC records that in Australia fluorosis has declined as water fluoridation expanded, because exposure from other sources was reduced (notably low-fluoride children's toothpaste and guidance to use "only a small pea-sized amount"). Where it is identified here, "in most cases it is classified as very mild or mild", which "does not affect the function of the teeth, is not of aesthetic concern to those who have it and is associated with a protective benefit against tooth decay in adult teeth". Moderate fluorosis is very uncommon and severe fluorosis is rare, and the NHMRC states that the small amount of moderate and severe fluorosis in Australian children aged 8 to 14 "is not statistically different between fluoridated and non-fluoridated areas".

One regulatory point that often gets misreported: in Australia the Therapeutic Goods Administration does not require fluoride compounds added to toothpaste or to community drinking water to be registered as medicines when used for the prevention of dental decay, nor are they scheduled as drugs or poisons when added to water supplies.

And the part that matters for this page: water and toothpaste are not substitutes. On the NHMRC's account, "fluoridated water keeps low levels of fluoride in saliva and in dental plaque all day" while the higher concentration in toothpaste adds more — "together, the two sources offer more protection than using either one alone". If you drink filtered, tank or bottled water, you have removed the background and the toothpaste is doing all the work. See fluoridated water — is it good for you?

Is fluoride toothpaste safe for my children, and how much should they use?

Yes, at the amount appropriate for the age — and the amount is the whole question. Fluorosis is caused by swallowing fluoride from several sources during the years the teeth are forming. The NHMRC dates that window precisely: "usually from birth to six or eight years of age", while the teeth are still developing inside the jawbone. It appears as "white lines or areas on the surface of both primary and permanent teeth" and is only identified once the teeth come through.

Which is why the advice is about dose rather than avoidance. The NHMRC links Australia's declining fluorosis to exactly two measures: low-fluoride children's toothpaste, and the public guidance to "use only a small pea-sized amount" and to "encourage children not to swallow toothpaste".

Practical points that follow:

• Keep toothpaste out of reach between brushings. Repeated swallowing of larger amounts during tooth development is the risk; correctly dosed brushing is not.
• Supervise or help with brushing while a young child is still learning to spit rather than swallow.
• Spit, do not rinse — the same rule as for adults, and for the same reason.
• Do not add supplements on top. As above, fluoride drops and tablets are for an oral health professional to advise on, and the NHMRC notes they are no longer readily available here.

If you are worried about a mark that has already appeared, it is worth having it identified rather than assumed: early decay, fluorosis and molar hypomineralisation all show up as white marks and are managed very differently. See what causes white spots on teeth? and my child has chalky teeth, now what?

Related reading

• Caring for your teeth: 8 steps to dental health
• 10 ways to avoid ruining your teeth
• The three layers of dental wellness and longevity
• I am in my late 60s — how can I keep my teeth in top condition now that I am older?
• Protecting your child from dental disease

Practical details

Figures and positions attributed to the World Health Organization, the NHMRC, the Australian Dental Association and published caries-prevention research are those sources’ own, as at the dates of the documents cited.

Specialist registration can be verified on the AHPRA register, or by calling 1300 419 495. The practice’s registered specialists are identified as such within the full team.

Smile Solutions, Level 1, 220 Collins Street, Manchester Unity Building, Melbourne VIC 3000 — getting here. Phone 13 13 96, contact us, or theteam@smilesolutions.com.au. Monday–Friday 8.00am–6.00pm, Saturday 8.30am–1.30pm, Sunday by appointment.

Published 8 May 2017. General information only; it does not replace advice from your treating practitioner.

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