Five-way fix: Bright Whites

Media item: magazine feature

Date published: 1 October 2013

Subject: tooth colour and appearance

This page records the media item. The original feature is the property of its publisher and is not reproduced here.

‘Whitening’ is five different problems wearing one word

Magazine features on brighter teeth almost always assume one problem with one solution: bleaching. In practice, teeth look dull or discoloured for at least five distinct reasons, and bleaching addresses only one of them.

This is why people are disappointed. They buy the treatment for problem two while they have problem four.

An examination separates them. That is the entire value of assessment before treatment, and it takes minutes. It is also what the profession requires: the Australian Dental Association's policy on teeth whitening states that whitening ‘should only be performed if the treatment can be justified, and after a comprehensive dental examination has been conducted by a Dental Practitioner’, because ‘appropriate examination to diagnose and treat any dental or oral health problems is required to minimise any potential discomfort or health risks associated with exposure to bleaching agents’.

1. Extrinsic staining — stain sitting on the surface

What it is: pigment from coffee, tea, red wine, dark cola, curry and tobacco adhering to the acquired pellicle on the enamel surface, plus calculus that has taken up colour.

How you tell: it is worse near the gum line and in the grooves, it is often uneven, and it accumulated gradually.

The fix: a professional clean. Scaling and polishing removes it mechanically. Peroxide does not remove calculus and never has — whitening a mouth with build-up on it whitens the parts you can already see and leaves the rest. What a hygienist visit involves is set out separately.

Cost: the lowest of the five. This is the most commonly skipped step and the most commonly needed one.

2. Intrinsic discolouration — colour inside the tooth

What it is: pigmented organic molecules within the enamel and dentine, accumulated over years.

How you tell: it is even across the tooth, symmetrical, and present even on freshly cleaned teeth.

The fix: this is what bleaching treats, and treats well. Hydrogen or carbamide peroxide diffuses into the tooth and oxidises those molecules. In-chair and take-home reach a similar endpoint at different speeds.

The concentrations, and the law around them. This is where a dental product and a shop product genuinely differ. The ADA's policy records that Schedule 10 of the Poisons Standard 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’, and that those provisions are ‘formalised in all state and territory poisons legislation’. Below that line, hydrogen peroxide at 3–6% and carbamide peroxide at 9–18% are Schedule 5 substances requiring ‘Caution’, and can be sold direct to consumers. The two scales convert at roughly one-third: ‘18% carbamide peroxide approximates 6% hydrogen peroxide’. In practice the ADA describes effective concentrations ranging from as low as 3–6% in some products supplied for home use to 35% in some office-based products. The Dental Board of Australia puts the same rule 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).’

The side effects, which features rarely mention. The ADA names the most common as ‘transient tooth sensitivity and soft tissue irritation during or immediately following treatment’, and notes that ‘the potential for adverse effects on the oral tissues is increased when higher concentrations are used’ — which is the reason the higher concentrations are restricted to practitioners rather than a matter of professional territory.

The limits: it does not touch any restoration, and it does not last forever.

3. Thinning enamel — the yellow underneath showing through

What it is: enamel is translucent and slightly blue-white; the dentine beneath it is genuinely yellow. As enamel thins, more dentine shows through and teeth look darker. Enamel thins with age, with abrasive brushing, and — fastest of all — with acid erosion from soft drinks, sparkling water, citrus, sports drinks, reflux and vomiting.

How you tell: the teeth look more yellow and more translucent at the edges, and the incisal edges may look glassy or grey.

The fix: bleaching helps very little here, because the problem is structural, not chemical. What matters is stopping further loss — identifying the acid source, remineralisation with fluoride, avoiding brushing straight after acid exposure. Where the appearance genuinely matters, the restorative options are bonding or veneers, which are irreversible and expensive.

This is the category most often mis-sold as whitening, and the one where whitening produces the most disappointment. Abrasive ‘whitening’ toothpastes and charcoal make it worse permanently.

4. Mismatched or ageing restorations

What it is: an old composite filling on a front tooth that has stained at the margins, or a crown that was matched to a shade you no longer have.

How you tell: one tooth or one patch is out of step with the rest.

The fix: replace or repolish the restoration. No amount of peroxide changes it.

The trap that catches people out: whitening natural teeth around an existing crown or veneer leaves the restoration exactly the shade it was, so it then looks dark. The replacement cost belongs in the decision before whitening, not after — and if it is a front crown, that cost can exceed the whitening several times over.

5. Alignment, shape and framing — which is often the real complaint

What it is: rotated, crowded or worn teeth catch light unevenly and read as ‘not bright’, regardless of shade. So do uneven incisal edges, chips, a gummy smile, and a midline that does not sit with the face.

How you tell: the complaint is usually phrased as colour but the photographs show shape.

The fix: orthodontics, edge recontouring, bonding, or nothing. It is worth naming because spending money on whitening will not address it, and a practitioner who does not distinguish it is treating the wrong problem. Where to start if you want to change your smile is a better first question.

The sixth thing, which is not a fix

Photographs lie. Front-facing phone cameras use short focal lengths that distort, filters brighten teeth automatically, and social media whitening is a rendering choice. Nobody's teeth are the colour they are on Instagram.

That is not only a consumer observation; it is written into the advertising rules. AHPRA's Guidelines for advertising a regulated health service warn that before-and-after images ‘have the potential to be misleading or deceptive’ and ‘may cause a member of the public to have unreasonable expectations of a successful outcome’, and that advertising may breach the National Law where ‘images are not genuine and/or have been edited or enhanced’. The conditions AHPRA sets are a useful checklist for a reader looking at anyone's gallery: the images should be as similar as possible in content, camera angle, background, framing and exposure; posture, clothing and make-up consistent; lighting and contrast consistent; any alteration explained; and the treatment itself ‘the only visible change to the person being photographed’.

So does lighting. Teeth look darker under warm domestic light and lighter under the cool bright light of a bathroom mirror or a dental surgery — which is one reason results can look better in the chair than at home.

And dehydration: teeth dry out during a long appointment or after in-chair whitening, which temporarily makes them look lighter. That rebounds over the following days. The result you should judge is the one a week later, not the one in the mirror on the way out.

What a realistic sequence looks like

If brighter teeth are the goal, the order that gets the most result per dollar is usually:

1. Examination and a professional clean. Remove surface stain and calculus, and rule out decay and gum disease — both of which make whitening more uncomfortable and less effective. This is also the step the ADA and the Dental Board both treat as a precondition rather than an option, the Board listing ‘carrying out an appropriate assessment and examination’ among what is expected of a practitioner.
2. Identify which of the five you actually have. Often it is more than one.
3. Address erosion or abrasion if present, before anything cosmetic. There is no point brightening a surface you are still losing.
4. Whitening, if intrinsic colour is the issue — usually custom trays, with or without an in-chair session. The pharmacy kits are a weaker formulation, not the same thing cheaper: by law a product sold direct to you cannot exceed 6% hydrogen peroxide or 18% carbamide peroxide.
5. Restorative work last, so that new restorations are matched to the final shade rather than the starting one. Doing crowns or veneers before whitening locks in the old colour.

Two honest cautions

Nobody can promise a specific shade. Teeth respond individually, and the advertising rules for regulated health services in Australia prohibit promising a particular outcome — section 133 of the National Law bars advertising that ‘creates an unreasonable expectation of beneficial treatment’, and AHPRA's guidelines add that care is needed with any visual representation because ‘the outcomes experienced by one person do not necessarily reflect the outcomes that other people may experience’. A practitioner who names a guaranteed end shade is either guessing or breaching the rules.

Natural teeth are not white. Healthy enamel is a warm off-white, and canines are naturally darker than incisors. A uniformly flat bright white across every tooth is a restorative appearance, not a bleached one — which is worth knowing before comparing yourself with images of it.

Common questions

There is a whitening kiosk at the shopping centre for a quarter of the price. What is the difference?

The difference is what may lawfully be used and who is allowed to decide whether it is safe for you.

The ADA's policy records the growth of this market directly: whitening services ‘are now also increasingly offered by unregulated, unqualified non dental practitioners in settings such as beauty and hair salons, shopping mall kiosks, dedicated teeth whitening salons, or via mobile services that travel to a location convenient to the consumer’. It also notes that many such services claim their operators have the knowledge or training to perform whitening safely, and answers that claim in one sentence: ‘only registered dental practitioners have the expertise to assess whether bleaching is safe for individual patients, to recommend the most appropriate technique and materials, and to provide treatment that meets regulated safety and quality standards of care.’

The legal position is the practical one. Under Schedule 10 of the Poisons Standard, products above 6% hydrogen peroxide or 18% carbamide peroxide ‘may only be sold, supplied and used by registered dental practitioners as part of their dental practise’. A salon or kiosk therefore cannot lawfully use the concentrations that do the work, which is one reason the price differs — and if a non-dental operator is using something stronger than that, the product is the problem, not the price.

The other half is the examination. Nobody at a kiosk is looking for the untreated decay, the exposed dentine, the crack or the gum disease that make whitening painful or ineffective — and the ADA treats that examination as a precondition, not an upsell.

How dangerous is the material itself?

Handled properly, the common side effects are minor and temporary — the ADA names ‘transient tooth sensitivity and soft tissue irritation’. Handled badly, the potential harms are not minor, and the ADA's policy sets them out at more length than most consumer material does.

• Concentration. ‘WorkSafe Australia's current guidelines designate hydrogen peroxide at concentrations above 5% as a hazardous substance.’
• Contact. ‘Direct exposure of the skin, eyes and mucous membranes to hydrogen peroxide may cause severe irritation or burns, while ingestion may cause irritation to the oesophagus and stomach resulting in bleeding or sudden distension.’ This is why isolating the gums and lips is part of the procedure rather than fussiness.
• Reaching the nerve. ‘Percolation of hydrogen peroxide into the nerve tissues — often accelerated by exposed dentine and enamel fractures — can lead to nerve inflammation.’ That is the specific reason cracks, wear and exposed root surfaces need to be found before whitening, not after it starts hurting.
• Lights and lasers. ‘The incorrect application of heat and other forms of energy during teeth whitening procedures, such as light from a plasma arc lamp or high-power (Class 4) laser may cause nerve damage to the tooth and burns to adjacent soft tissues, and failure to ensure use of the appropriate protective eyewear may also cause irreversible injury.’ There is an Australian standard for this — AS/NZS 4173:2018, Safe use of lasers and intense light sources in health care — and the ADA notes that in Western Australia, Queensland, Victoria and Tasmania a practitioner must first hold a licence from the state regulator to use a Class 4 laser.

If eyewear is not offered and the soft tissues are not isolated, those are the two things to notice before anything is switched on.

Can I just keep topping it up forever?

That is exactly what the products are sold on, and it is the part the ADA singles out as unsupported. Its policy states that ‘The marketing of some teeth whitening products directly available to Australian consumers encourages unrealistic expectations about whitening results and promotes regular ongoing use to maintain desired effects. This is a concern given the lack of clinical data supporting frequent home use of such products over long periods.’

So the honest answer is that nobody knows what indefinite low-level use does, because it has not been studied at that duration. What is known is that two of the five problems on this page get worse with the wrong maintenance: abrasive ‘whitening’ pastes and charcoal remove enamel, and enamel loss makes teeth look darker, not lighter. A top-up on a practitioner's advice, at an interval they set, is a different thing from a permanent daily habit bought online.

If the colour is not holding, the useful question is which of the five problems is actually driving it — returning surface stain from coffee and wine is a clean, not a bleach.

What should actually happen before anyone whitens my teeth?

Three things, and all of them are documented requirements rather than courtesies.

An examination. The ADA: whitening ‘should only be performed if the treatment can be justified, and after a comprehensive dental examination has been conducted by a Dental Practitioner’. The Dental Board's guidance adds the components — ‘carrying out an appropriate assessment and examination’, ‘considering their history’, and ‘applying the principles of risk minimisation and management’.

A conversation about expectations. The ADA: ‘Practitioners should ensure that patients have realistic and reasonable expectations regarding the results of the bleaching treatment.’ AHPRA's guidance to practitioners puts the same point as an obligation: ‘Justifying the treatment includes knowing the patient's expectations of the products and explaining the risks.’

Consent that includes the money. The ADA: ‘Risks and costs associated with the treatment should be explained to the patient and documented along with informed consent.’ AHPRA is more explicit still: ‘You must have and document their informed consent, including financial consent.’ If the cost of the top-up trays, the refills and any restoration that will need replacing afterwards has not been named, the financial consent is incomplete.

One thing that is not a rule, despite being widely assumed: AHPRA states plainly that ‘No current laws or regulations limit teeth whitening products to in-clinic use.’ Take-home trays supplied by a dentist after an examination are entirely orthodox. Price Guide.

I found a 35% kit online. Is that legal, and what happens if it goes wrong?

Not legal to supply to you in Australia, and the answer to the second half is the real reason not to.

On legality, the ADA's policy notes that ‘From time to time, some products containing concentrations of bleaching agents that exceed legal limits in Australia have been found to be available online to Australian consumers’. The limit for direct-to-consumer sale is 6% hydrogen peroxide or 18% carbamide peroxide; a 35% product is in the range Schedule 10 reserves to registered dental practitioners in practice. An offshore seller is simply outside the reach of the rule.

On recourse, the contrast is stark. When an Australian dental practice supplies you with a take-home product, the Dental Board lists what follows: obligations under the Australian Consumer Law including ‘consumer-guarantees that products are of acceptable quality’, ‘replacing, repairing or refunding a product in certain circumstances’, and ‘compensating a patient for damages and loss’. The practitioner is also registered, which means their conduct can be the subject of a notification to AHPRA and their registration can be checked free at ahpra.gov.au.

An online seller in another jurisdiction gives you none of that — no examination, no consumer guarantee you can enforce, no registration to check, and nobody to treat the chemical burn or the sensitised tooth. If a whitening product is strong enough to be restricted, the restriction is the safeguard, not the obstacle. Why should I go to a dentist for teeth whitening?

Related reading

• Professional teeth whitening and how can I improve the whiteness of my teeth?
• Teeth whitening interview with Dr Kat Marhfour
• White fright: burns and multicoloured teeth
• Why should I go to a dentist for teeth whitening?
• Before & after gallery and Dental Myth Busters
• More coverage in Our Media

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This page records a published feature and its date, with general information. It is not a diagnosis, a treatment plan or a promise of any particular result. Cosmetic dental treatment carries risks and results vary between individuals. Concentration limits and scheduling are set in the Poisons Standard and revised from time to time; confirm the current position rather than relying on a figure quoted here. Third-party published content is not reproduced.

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