Dental Myth Busters

Media item: article and video on common dental misconceptions

Date published: 11 March 2011

This page records the media item. The original content is the property of its publisher and is not reproduced here. What follows is an independent, evidence-based treatment of the same subject.

Myths that are simply wrong

"Baby teeth don't matter — they fall out anyway"

Wrong, and among the most costly beliefs in dentistry. Primary teeth hold space for the permanent teeth; losing one early lets the neighbours drift, which produces crowding and impaction later. Decay in them causes pain, infection and time off school, and infection can damage the developing permanent tooth beneath. The last baby teeth are not lost until around age eleven or twelve — a decade of service.

"Bleeding gums are normal"

Wrong. Healthy gums do not bleed. It is the earliest sign of gum disease, and it is the one most people ignore. Bleeding is a reason to clean better, not less — and a reason to have your gums measured.

"If it doesn't hurt, nothing is wrong"

Wrong, and dangerously so. Gum disease is painless until it is advanced, by which point substantial bone has gone — and lost bone does not grow back. Decay between teeth is painless until it reaches the nerve. Oral cancer is frequently painless in its early stages — the Royal Australian College of General Practitioners puts it as “Initial lesions of oral cancer are generally painless”, which is precisely why it advises acting on “any unexplained and/or non-healing changes or symptoms in the mouth for more than two to three weeks”, such as a persistent ulcer, red or speckled patches, lumps or a sore throat. The Victorian Department of Health's Better Health Channel sets the same threshold: “If you notice a mouth ulcer that lasts for longer than 2 weeks, get it checked by a dentist as soon as you can.” Pain is a late signal in dentistry, not an early one.

"Whitening damages enamel"

Wrong at the concentrations used clinically. Peroxide oxidises pigmented molecules within the tooth; it does not soften or thin enamel. The Australian Dental Association's position statement on whitening says that “Teeth bleaching products are safe and effective when used by or under the supervision of a dentist and according to the professional directions for use”, and that “The most common side-effects are transient tooth sensitivity and soft tissue irritation during or immediately following treatment” — sensitivity is common and usually temporary.

There is a real risk in the vicinity of this myth, and it is not the enamel. The same statement warns that “Percolation of hydrogen peroxide into the nerve tissues — often accelerated by exposed dentine and enamel fractures — can lead to nerve inflammation”, which is the argument for an examination before whitening rather than after. What is also true: abrasive whitening products — charcoal in particular — remove stain and enamel together. What to know about whitening is set out separately.

"Charcoal toothpaste is natural, so it's better"

Wrong. It is abrasive, most formulations contain no fluoride, and no benefit has been demonstrated. It also scratches existing restorations.

"A supermarket whitening kit is the same thing, cheaper"

Wrong, and this one is settled by law rather than opinion. Australia scales whitening products by peroxide concentration. The ADA's account of the Poisons Standard is that hydrogen peroxide at 3% to 6% and carbamide peroxide at 9% to 18% are Schedule 5 substances requiring a “Caution” label, so products at those strengths “can be sold direct to consumers if they are labelled with stipulated safety warnings” — whereas “Schedule 10 specifically states that teeth whitening products containing more than 6% hydrogen peroxide or 18% carbamide peroxide may only be sold, supplied and used by registered dental practitioners as part of their dental practise.” Schedule 10 exists for substances “of such danger to health as to warrant prohibition of their sale, supply and use other than in specified exempt circumstances.” The Dental Board of Australia says the same thing in one line: “Australian laws mean only registered dental practitioners can use or supply high-concentration teeth whitening products (over 18% carbamide peroxide or 6% hydrogen peroxide).” A retail kit is therefore a genuinely weaker formulation, not the same product at a discount.

"Harder brushing cleans better"

Wrong. It causes gum recession and worn notches at the gum line, both permanent. Soft brush, light pressure, and technique over force.

"You should rinse after brushing"

Wrong — spit, don't rinse. Rinsing washes away the fluoride doing the work. One of the highest-value pieces of advice in dentistry, and almost nobody has been told it. The World Health Organization notes what that fluoride is doing: alongside high free-sugar intake, “a lack of removal of plaque by toothbrushing with fluoride toothpaste containing 1000-1500 ppm concentration can lead to dental caries.”

"Sugar-free drinks are safe for teeth"

Wrong. The decay risk falls; the acid remains, and acid dissolves enamel directly. Frequency and contact time matter more than volume — sipping across an afternoon is far worse than drinking quickly, and soda water is not exempt. On the sugar side of the same question, note that the profession does not rank the variables the way popular advice does: the ADA's position is that “The form, frequency, timing and total amount of sugar intake are significant in the initiation of the caries process” — all four together — and the WHO's population target is on the amount, “Limiting the intake of free sugars to less than 10% of total energy intake – and ideally to less than 5% – minimizes the risk of dental caries throughout the life course.”

"An aspirin held against a sore tooth helps"

Wrong, and it causes a chemical burn of the gum and cheek. Aspirin works systemically, not by contact. What actually relieves a toothache is covered separately. While on the subject of the wrong remedy: the RACGP's position on dental infection is that “Antibiotic treatment without dental treatment to remove the cause always fails.”

"Removing amalgam fillings improves your health"

Not supported by evidence. Amalgam use is declining, driven principally by the international Minamata Convention on mercury and by aesthetics — not by demonstrated harm to patients from existing fillings. Removing sound amalgam for health reasons destroys tooth structure for no established benefit. The materials compared are set out separately. In fairness to the reader: we have not found an Australian regulator's statement on composite or amalgam safety in the independent sources we work from, so treat the paragraph above as the mainstream professional position rather than a quoted guideline.

"Root canal treatment causes disease elsewhere in the body"

Wrong. This originates in early-twentieth-century "focal infection" theory, which was abandoned as the evidence failed. It recirculates online and it has no credible support. What root canal treatment actually involves is a better guide. On what root canal treatment does achieve, a long-term study of primary root canal treatment reported overall success of 87.8% at tooth level (95% CI 84 to 90%) and 80.8% at patient level (95% CI 75 to 86%).

"Mouthguards prevent concussion"

Not supported. They demonstrably reduce dental and soft-tissue injury, which is reason enough. It is worth noticing what the Australian Dental Association's Policy Statement 2.2.5 claims for them and what it does not: it covers “broken jaws, fractured, cracked or knocked-out teeth, cut lips and tongues” and states that “The cost of an injury to the teeth or jaw far exceeds the cost of a mouthguard” — and it says nothing at all about concussion. Neither does its consumer guidance. An authority that recommends mouthguards strongly, and still does not claim a concussion benefit, is the most telling evidence available on the point.

"Fluoride is dangerous"

At the concentrations used in water fluoridation and toothpaste, no. Water fluoridation is among the most examined public health measures anywhere, and remains the most cost-effective population measure available against decay. The National Health and Medical Research Council reviewed the evidence relevant to Australia and, in its own words, “confirmed that community water fluoridation helps to reduce tooth decay, and that there is no reliable evidence that water fluoridation at current Australian levels causes health problems.” It describes community water fluoridation as “a safe and effective way of reducing tooth decay across the population.” Excessive fluoride during tooth development can cause fluorosis — which is why children under three use a smear rather than a pea-sized amount, and why toothpaste is kept out of reach. The contrary case has also been put.

Myths that are actually true

"Some people are just more prone to dental problems"

True. Genetic susceptibility to periodontitis is real — two people with identical plaque levels can have very different outcomes. Saliva flow and composition vary. Enamel defects such as molar incisor hypomineralisation affect a significant proportion of children and are not caused by anything the parent did.

"Pregnancy affects your gums"

True. Hormonal change produces an exaggerated inflammatory response to plaque — pregnancy gingivitis. Dental treatment during pregnancy is safe and appropriate, and the second trimester is generally most comfortable. "You lose a tooth for every baby" is folklore; the underlying gum change is not.

"Dry mouth wrecks teeth"

True, and badly under-appreciated. Several hundred common medications reduce saliva, and the effect compounds across multiple medications. Without saliva, decay progresses rapidly and in patterns that do not otherwise occur. Ageing itself is not the cause — the association is really with medication use.

"Grinding your teeth is doing damage"

True as far as the teeth go — but the framing has changed, and the change is worth knowing. Grinding wears enamel flat, fractures teeth and restorations, and causes jaw muscle pain. A night guard protects the teeth; it does not stop the grinding.

What has moved is whether grinding is itself a disorder. An international consensus meeting reported in the Journal of Oral Rehabilitation in 2025 concluded that “Bruxism is a motor behaviour rather than a disorder”, and that it “can be a risk factor, protective factor or neutral factor. Since it is a behaviour, it cannot be a comorbidity.” The consensus even records that a protective role has been proposed. So the honest version of this entry is: grinding can damage teeth and often does, and that damage is worth preventing — but finding that someone grinds is not by itself a diagnosis, and the older habit of grading everyone's bruxism has been retired.

Things that are more complicated than either

"You need a check-up every six months"

Six months is a convention, not evidence. The interval should match your risk. Some people need three-monthly; many low-risk adults are safe at twelve.

"Flossing doesn't work"

The systematic reviews say the studies are small, short and poor — not that interdental cleaning is useless. That was widely misreported. The biological case is strong, and interdental brushes have better supporting evidence than floss for most adults with any recession.

"Mouthwash does the job instead"

No — and the Australian sources are careful about exactly how they put it. Australian Prescriber, the most senior Australian clinical source on mouthwashes as a product class, states that “Mouthwashes are an adjunct to, not a substitute for, regular brushing and flossing” and that a rinse “should never be the sole means of oral hygiene.” The Australian Dental Association's framing is consistent with that and is not dismissive: it lists mouthrinse among the proven aids to oral hygiene, alongside fluoridated toothpaste, interdental cleaning and sugar-free chewing gum — an aid to be used with brushing and professional care, not a replacement for any of them. So the answer is not that mouthwash is useless; it is that it is additional. Where a rinse has good evidence it is for a defined purpose — Cochrane has reviewed chlorhexidine rinses for gingival health in the general population, and fluoride rinses for decay — rather than as a general substitute for cleaning.

The alcohol-and-oral-cancer question that circulates alongside this one is genuinely unresolved, and we are not going to resolve it here. The strongest Australian wording on it dates from 2009 and rests on the same authors' own earlier review; later and larger epidemiology does not support that strength. Any page presenting the question as settled, in either direction, is overstating what is known.

"Gum disease causes heart disease"

There is a consistent statistical association. But treating gum disease has not been shown to prevent cardiovascular events, and major professional bodies have said so explicitly. The diabetes relationship is better established and bidirectional — the peer-reviewed position is that there is “emerging evidence to support the existence of a two-way relationship between diabetes and periodontitis, with diabetes increasing the risk for periodontitis, and periodontal inflammation negatively affecting glycaemic control.” Note the hedge in the source's own words: emerging. Gum disease is worth treating on its own merits.

"Wisdom teeth should all come out"

Not routinely — and the two most-cited authorities stop at different places, which is worth knowing rather than glossing. NICE, in its first technology appraisal (TA1, March 2000), said “The practice of prophylactic removal of pathology-free impacted third molars should be discontinued in the NHS” and that “There is no reliable research evidence to support a health benefit to patients from the prophylactic removal of pathology-free impacted third molar teeth” — a United Kingdom document, now a quarter of a century old, with no status in Australia. Cochrane, reviewing the same question in 2020, went less far: “Insufficient evidence is available to determine whether asymptomatic disease-free impacted wisdom teeth should be removed or retained.”

Removal is indicated for recurrent infection, unrestorable decay, damage to the adjacent tooth, or cyst formation. On the infection point NICE is specific: “a first episode of pericoronitis, unless particularly severe, should not be considered an indication for surgery. Second or subsequent episodes should be considered the appropriate indication for surgery.” Prophylactic removal of all four as a matter of course is not supported.

Common questions

I keep being told my bad breath comes from my stomach. Is that right?

Almost certainly not. Bollen and Beikler's review in the International Journal of Oral Science is blunt: “A majority of patients and physicians still abusively believes that halitosis originates from the stomach. The latter is only correct in <0.5% of the cases.” In a clinical evaluation of 2,000 patients, 76% had oral causes — tongue coating 43%, gingivitis or periodontitis 11%, both together 18% — against 4% from outside the mouth, and 16% had no objectively detectable malodour at all. So the first appointment to make is a dental one.

Does cleaning my tongue fix it?

The Australian Dental Association contradicts itself here, and seeing that is more useful than having it tidied away. Its key-messages box says “Cleaning your tongue can help to reduce bad breath”; the body of the same page says a 2019 review “found no evidence that cleaning your tongue, using several different methods including mouthwash or chewing gum, were effective for managing the cause of halitosis.” That review is Cochrane's — 44 trials, 1,809 participants — and its conclusion is “We do not have enough evidence to say which intervention works better.” Clean gently if you like how it feels. Do not expect it to be the treatment.

Is oil pulling worth trying?

Nobody can honestly tell you. No policy statement, guideline or trial on oil pulling appears in any of the independent sources this site works from — not the ADA, not an Australian government health body, not Cochrane. That is not evidence that it fails; it means the claim has never been tested to a standard anyone can cite. What matters is what it is usually proposed to replace, and those things are established: fluoride toothpaste twice daily, cleaning between the teeth, and cutting how often sugar is eaten.

A dentist says a tooth is cracked, but the X-ray looked normal. Is that possible?

Yes — that is the usual case. The European Society of Endodontology's 2024 position statement records that only 2% of cracked teeth with living pulps showed any evidence of a crack on a radiograph, and that cone beam CT “is not predictable in detecting cracks”. Diagnosis is clinical: where it hurts, what provokes it, what is visible under magnification. In a practice-based study of 2,858 cracked teeth, 45% were symptomatic, and after restoration 7.7% to 20% later needed root canal treatment. The statement also finds “no clear evidence on the most suitable restorative treatment approach” — so two differing repair proposals may both be defensible.

My jaw clicks, so my bite must be wrong. Isn't it?

The major authorities now reject that. The US National Academies' 2020 report concludes that “occlusion should not be considered a contributing cause for the common TMDs.” The RACGP draws the consequence: “Malocclusion of the teeth should be noted if present; however, this does not contribute to the manifestation of TMD and orthodontic referral is not recommended for this finding alone.” It also records that up to 40% of symptomatic patients resolve without any treatment and 50–90% get relief from conservative therapy, calls splint evidence “inconclusive”, and notes that immobilising the joint “has no benefit and may actually worsen symptoms.” A 2023 BMJ guideline makes a strong recommendation against irreversible oral splints.

Practical details

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

This page records a media item and its date, with general information. It is not a diagnosis, a treatment plan or a promise of any particular clinical outcome. Third-party media content is not reproduced.

Smile Solutions trades under ABN 28 193 514 103.