The five questions patients think but don’t ask

Most people have had a question surface while reclining in the dental chair and decided not to ask it. Dr Kia Pajouhesh, Smile Solutions’ Managing Director and Principal Dentist, answered the five most common.

His answers are below, each followed by the fuller explanation — because in every case the honest answer is more useful than the polite one.

1. Can you smell our breath through your mask?

Dr Pajouhesh: if it’s bad enough, yes.

Worth knowing rather than worrying about: a dentist who notices is also the person best placed to tell you why, and bad breath almost always has a specific and treatable cause.

The detail. The figure usually quoted is that 85 to 90 per cent of persistent bad breath originates in the mouth rather than the stomach. That number deserves stating more carefully, because it is not the number the underlying study published. In Quirynen and colleagues’ series of 2,000 consecutive patients at a dedicated bad-breath clinic in Leuven (2009), an oral cause was identified in 76 per cent — most often coating on the back of the tongue (43 per cent), gum disease (11 per cent), or both together (18 per cent). Around 16 per cent had no objectively detectable odour at all, and 4 per cent had an ear, nose and throat or other cause outside the mouth. The familiar 85 to 90 per cent comes from re-basing those figures to exclude the group with nothing to detect. These were self-selected attenders at a referral clinic who had been complaining for a mean of seven years, not a general-practice population, so read it as the pattern of causes rather than as a percentage that applies to you. That 16 per cent matters in its own right: some people who are certain their breath smells have no odour anyone else can detect, which is a recognised presentation with its own management, and more brushing is not it.

The mechanism is not in dispute. Bacteria break down proteins and produce volatile sulphur compounds, and those are the smell. What causes bad breath and how can I fix it? goes through the causes one by one.

The most common single source in that series was the back of the tongue, which is rough, poorly cleansed and holds a large bacterial load. Most people never clean it. What follows from that is less certain than it is usually made to sound. The Australian Dental Association’s own consumer page on tongue cleaning states that “a review of the scientific evidence in 2019 found no evidence that cleaning your tongue… were effective for managing the cause of halitosis”, and that the impact of reducing tongue bacteria “has not been proven yet”. Cochrane’s 2019 review, Interventions for managing halitosis (CD012213), compared mechanical tongue cleaning with no tongue cleaning and found a change in dentist-rated odour scores of MD −0.20 (95% CI −0.34 to −0.07) from 2 trials and 46 participants, rated very low certainty — a direction of effect, not a demonstrated treatment.

The ADA page contradicts itself here, and we are not going to resolve that for them: its key-messages box says cleaning your tongue “can help to reduce bad breath”, while the body of the same page reports that the 2019 review found no evidence that it works. So: cleaning the back of the tongue is cheap, gentle if done properly, and reasonable to try. It is not established as a treatment. The ADA adds that “you need to be very gentle because the tongue surface is delicate and sensitive”, and to “start gently at the back of the tongue, pulling or brushing forward and use water to lubricate the process”. See do I need to use a tongue scraper? and should I use a tongue scraper?

The other common source is gum disease — deep periodontal pockets are anaerobic and produce exactly these compounds. Persistent bad breath with bleeding gums is gum disease until proven otherwise, and no amount of home care will fix it if the pockets are deep — see when do you need deeper cleaning? and periodontal (gum) disease.

What does not work: mouthwash masks for under an hour and treats nothing; alcohol-based rinses can dry the mouth and make it worse — see the truth and myths about mouthwashes and should I be using mouthwash as well as brushing and flossing? Sugared mints feed the bacteria. Charcoal products abrade enamel — home whitening and charcoal whitening: does it work? Is it safe? Sugar-free gum genuinely helps — not for the flavour, but because it stimulates saliva. Does chewing sugar-free gum really help prevent cavities? sets out how far that goes. If your mouth is persistently dry, that is its own problem — my mouth is always dry.

And the awkward physiological fact: you cannot smell your own breath. You adapt to it. Breathing into a cupped hand does not work either. Ask someone you trust.

More at Bad Breath, how do I get rid of my bad breath? and 7 ways to avoid bad breath.

2. Does flossing really make a difference?

Dr Pajouhesh: absolutely it does. Flossing is crucial for healthy teeth and gums, and for fresh breath.

A toothbrush cannot reach between the teeth. Those surfaces are where the cavities you cannot see tend to form, and where gum disease usually starts.

The detail. A toothbrush reaches roughly three of the five surfaces of every tooth. The two it misses are where most adult decay and most gum disease begin, and they are also the surfaces you cannot inspect in a mirror — which is why these problems are typically found on a radiograph rather than noticed. Is flossing really that important? is the longer answer.

This is also the profession’s own position rather than a practice preference. The Australian Dental Association’s Policy Statement 2.2.3 on oral hygiene lists cleaning between the teeth among the main oral hygiene strategies — “clean between teeth once a day using floss or interdental brushes” — alongside brushing for two minutes twice a day, an age-appropriate fluoride toothpaste, and regular professional check-ups and cleaning. Note how that is phrased: floss and interdental brushes appear as alternatives, with no hierarchy between them, and the same policy counts both among what it calls “proven aids to oral hygiene”. Where the spaces between teeth are large enough to admit them, many people find interdental brushes easier to use well, and technique is most of what determines whether interdental cleaning works at all. Floss remains the right tool where teeth are tight, and under bridges a floss threader or superfloss is needed.

The practical point is that cleaning between the teeth happens daily, with whichever tool actually gets used. A perfect technique performed twice a year is worth nothing; an adequate one performed nightly is worth a great deal. Ask to be shown on your own mouth — the sizes of interdental brush that fit your gaps are specific to you, and the hygienist appointment is where that demonstration belongs. See the ideal daily routine for oral hygiene and, on the other failure mode, over brushing.

3. Can you tell what we’ve been drinking by looking at our teeth?

Dr Pajouhesh: often, yes.

• Sports drinks and fizzy drinks leave their damaging mark in several ways — acid erosion as well as decay. See what are sports drinks really doing to your teeth? and are sugar-free soft drinks better for my teeth?
• Tea, coffee and red wine cause staining — what impact does wine have on my teeth?

The distinction matters: staining is cosmetic and removable. Acid erosion is structural and permanent. Staining responds to a clean or to whitening; erosion does not — see what is dental erosion and how is it addressed? and what is acid wear and how can I avoid it?

The detail. Enamel begins to dissolve below about pH 5.5. Most soft drinks sit between pH 2.5 and 3.5 — and that includes sugar-free versions, because the acid is the phosphoric or citric acid, not the sugar. Sports drinks, energy drinks, sparkling water with added citrus, wine, and citrus juice are all acidic. See is soda water bad for your teeth? and damage to tooth enamel occurs within 30 seconds of consuming soft drinks.

Frequency matters far more than quantity. A can drunk in five minutes produces one acid challenge. The same can sipped across two hours holds the mouth below the critical pH for most of that time. The sipping is the damage. That is the Australian Dental Association’s position as well, and its Policy Statement 2.2.2 on diet and nutrition names it explicitly: “the form, frequency, timing and total amount of sugar intake are significant in the initiation of the caries process”, and public education should place “special emphasis … on the form, frequency, timing and total amount of sugar consumption; particularly snacking on sugary-beverages and/or sugar-rich foods that have limited nutritional value”. For children and young adults it goes further — “frequent consumption of drinks and foods with high sugar and/or acid content should be discouraged”. How does sugar affect your dental health? and how does acidic food affect your teeth? cover the same mechanism for food.

And the counterintuitive one: do not brush immediately after anything acidic. The enamel surface is temporarily softened, and brushing then removes it. Rinse with water, wait an hour, then brush.

Enamel does not grow back — if enamel is the hardest substance in the body, why do teeth break? Erosion is managed by stopping the cause and, where the damage is significant, by restoring what has been lost — which is expensive and gets more so. Compare the entries in the price guide.

4. Have you ever gone to bed without brushing?

Dr Pajouhesh: ‘Once in a long while — only to wake in the middle of the night with fuzzy teeth, and have to get out of bed for a good brushing.’

The detail, and the reason the night-time brush is the one that matters. Saliva is the mouth’s primary defence: it buffers acid, clears debris, and delivers calcium and phosphate back to the tooth surface. Salivary flow falls during sleep, which is also the accepted explanation for morning breath — healthdirect puts it plainly: “Your mouth produces less saliva overnight which allows bacteria to grow.” For eight hours the mouth’s own protection is at its lowest.

So: the last brush of the day is the important one, and nothing but water afterwards. See how often should I brush my teeth? and brushing your teeth: before or after breakfast?

The other thing almost nobody is told: spit, don’t rinse. Rinsing with water after brushing washes away the concentrated fluoride that would otherwise keep working on the tooth surface. This one is not folklore. healthdirect advises “spit out the toothpaste, don’t swallow it. Avoid rinsing with water”, and the Australian Dental Association’s own brushing instructions say to “spit out the excess toothpaste but do not rinse your mouth with water”, because that “allows the fluoride paste to sit on the teeth for longer, increasing protection”. The size of the effect has been looked for directly: a 2012 review in the British Dental Journal found four studies reporting a higher rate of new decay in people who rinsed with large volumes of water after brushing than in those who used little or none, with the difference ranging from 6 per cent to 16 per cent and statistically significant in three of the four. Spitting out the excess and leaving it is a free upgrade to the effectiveness of every brush you have ever done. On which paste, see choosing the right toothpaste.

5. I want to straighten my teeth but I’m strapped for cash. What can I do?

Dr Pajouhesh: people on a budget often opt for Invisalign, which costs less than internal lingual braces.

The aligners are removable for eating, drinking, flossing and brushing, which many patients see as a benefit in itself — cleaning is unchanged, where fixed braces make it considerably harder. See the hygiene benefits of Invisalign and, for the comparison across all three appliances, conventional braces vs lingual braces vs Invisalign.

It is worth having the conversation rather than assuming the cost. Smile Solutions offers a complimentary orthodontic consultation, publishes its Invisalign package pricing, and has payment plans available.

Confirm the current terms when you book — what the appointment includes, whether records such as scans or radiographs are part of it or charged separately, and whether any deposit applies.

Payment plan options are available. Where a plan is advertised as interest free, that describes the plan term only — a deposit may be required, an establishment fee and ongoing account fees may apply, and charges can apply if the balance is not cleared within the agreed period. The applicable terms depend on the provider and the amount financed, and are set out in writing before you commit — ask what the deposit and the establishment fee are, in dollars, and what the total will be by the end. Payment Plans.

The detail, and the part that matters most. Cost in orthodontics is driven by case complexity and treatment duration, not primarily by the appliance. A mild crowding case treated in six months costs a fraction of a complex case needing two and a half years, whatever it is treated with. So the only meaningful answer to ‘what will it cost’ comes after an assessment, and any quoted range before that is a guess. Published starting points are in Invisalign cost in Melbourne, broken down by treatment type, what is the cost of braces? and the price guide; how long treatment takes is in how long does orthodontic treatment take?

Conventional fixed braces are frequently the least expensive option for a complex case, and remain the most versatile appliance available. Aligners are excellent for many cases and are not suitable for all of them — how do I know which orthodontic treatment is best for me? and, for adults weighing it up, is having Invisalign as an adult worth it?

What to be careful of. Mail-order and remote ‘direct-to-consumer’ aligner services are marketed heavily on price. The Australian Dental Association takes a position on these and it is not a hedged one: on its consumer site it states that “the Australian Dental Association (ADA) do not recommend Australians have DIY orthodontic treatment”, that such treatment “can lead to permanent damage to your teeth, gums, and jaw joints”, and that it recommends instead “in-person treatment with a dentist or orthodontist which includes a thorough assessment before starting treatment and ongoing supervision”. The concern is not the plastic — it is that orthodontic tooth movement without an in-person examination and radiographs is undertaken without knowing the state of the roots, the bone or the gums. Moving teeth in the presence of undiagnosed periodontitis can cost you those teeth. An impression or a photograph is not a diagnosis. Who supervises the treatment matters too — see specialist orthodontist vs general dentist for Invisalign, orthodontic treatment: general dentist vs specialist orthodontist and our orthodontists.

Other genuine options if cost is the barrier:

• Ask what the cheapest clinically appropriate option is, explicitly. It is a fair question and a good practitioner will answer it.
• Ask whether limited treatment would do. Correcting the front teeth only is a legitimate, much cheaper plan where the bite is otherwise sound — and its limits should be explained to you. Where the concern is appearance rather than alignment, how can I change my smile naturally? and composite bonding may be relevant alternatives.
• Check your health fund. Orthodontic extras cover usually has a lifetime limit and waiting periods; know both before starting.
• Ask about the total, including retainers. Retention is lifelong and retainers get lost. That cost is real and belongs in the original conversation — see will my teeth need retainers after I’ve had braces?, why do teeth shift? and how to protect your aligners and your smile.
• A dental school or public orthodontic service may treat at reduced cost, with longer waiting times and eligibility criteria.

And the thing worth saying plainly: crooked teeth that are clean and healthy are not a disease. Orthodontics is worth doing for good reasons — function, cleanability, a bite that is damaging teeth, or because you want it. Being talked into it is a bad reason, and so is being unable to afford it and feeling you must. What is malocclusion of the teeth? sets out where the clinical reasons genuinely begin.

What dentists wish people would ask instead

Since the subject is questions:

• ‘Is this cavity actually cavitated, or is it early demineralisation that could remineralise?’ Early lesions do not need filling — can you reverse tooth decay?
• ‘If you are replacing an existing filling, what is wrong with it?’ Age is not an answer. See how long do dental fillings last?
• ‘What happens if I do nothing?’ A legitimate question with a real answer for every proposed treatment — understanding your treatment.
• ‘What are the item numbers?’ They let you check a health fund rebate and compare a quote.
• ‘Is there a more conservative option?’ Often there is, and it often is not offered unless asked for. If the answer does not convince you, a second opinion is routine.

Common questions

Can you smell our breath through your mask?

Dr Pajouhesh: if it’s bad enough, yes. Worth knowing rather than worrying about: a dentist who notices is also the person best placed to tell you why, and bad breath almost always has a specific and treatable cause.

Is bad breath coming from my stomach?

Usually not. In the largest series of its kind — 2,000 consecutive patients at a dedicated bad-breath clinic in Leuven, reported by Quirynen and colleagues in 2009 — an oral cause was found in 76 per cent, most often coating on the back of the tongue, gum disease, or both. Only 4 per cent had an ear, nose and throat or other cause outside the mouth, and 16 per cent had no odour that could be objectively detected. Those are referral-clinic figures rather than general-population ones, but the pattern is consistent: the mouth is the place to look first.

Will a tongue scraper fix it?

It might help and it will not hurt if used gently, but it is not established as a treatment. The Australian Dental Association’s own page on tongue cleaning says a 2019 review “found no evidence that cleaning your tongue… were effective for managing the cause of halitosis”, and Cochrane’s 2019 review (CD012213) rates the evidence for mechanical tongue cleaning very low certainty on 2 trials and 46 participants. The ADA page also contradicts itself, saying elsewhere that tongue cleaning “can help to reduce bad breath” — worth knowing that the disagreement is in the source, not in the reading of it. If bad breath persists, the question to answer is what is causing it, and deep gum pockets are the usual answer.

Does flossing really make a difference?

A toothbrush cannot reach between the teeth. Those surfaces are where the cavities you cannot see tend to form, and where gum disease usually starts. The ADA’s Policy Statement 2.2.3 on oral hygiene lists cleaning between the teeth once a day, “using floss or interdental brushes”, among the main oral hygiene strategies — and lists the two as alternatives rather than ranking them.

Can you tell what we’ve been drinking by looking at our teeth?

Often, yes — but the two effects are different. Staining from tea, coffee and red wine is on the surface and removable. Acid erosion from soft drinks, sports drinks and citrus is structural and permanent, and it happens with sugar-free versions too because the acid does the damage rather than the sugar.

Why does the night-time brush matter more than the morning one?

Saliva buffers acid, clears debris and returns calcium and phosphate to the tooth surface, and flow falls during sleep — healthdirect notes that “your mouth produces less saliva overnight which allows bacteria to grow”. For those hours the mouth’s own defence is at its weakest, so the last brush of the day is the one that has to happen, with nothing but water afterwards.

Does this article replace an individual dental assessment?

No. It provides general information. Symptoms, suitability, risks and treatment choices depend on examination and, where indicated, imaging or other records from an appropriately registered practitioner.

Sources named on this page

• Australian Dental Association, Policy Statement 2.2.3 — Oral Hygiene, and Policy Statement 2.2.2 — Diet and Nutrition
• Australian Dental Association consumer pages (teeth.org.au) on tongue cleaning and on teeth straightening and braces
• Cochrane Oral Health, Interventions for managing halitosis, CD012213 (2019)
• Quirynen M et al. (2009), 2,000 consecutive patients at a multidisciplinary bad-breath clinic, Leuven
• healthdirect Australia on halitosis and on dental care and teeth cleaning
• British Dental Journal (2012), post-brushing rinsing and dental caries

Related reading

• What makes a truly great dentist?
• Finding a dentist online in Australia
• How important is communication in dentistry?
• How often should I go to the dentist?
• Dental myths exposed
• Is it important to have a family dentist?

Related pages: Bad Breath, Invisalign® No Braces, Dental Cleans and Hygienists, Tooth Fillings.

Practical details

Answers from Dr Kia Pajouhesh, BSc, BDSc (Melb) — founder, Managing Director and Principal Dentist at Smile Solutions. A general dentist is not a specialist; specialist titles are protected under the National Law and require specialist registration — see dentists and registered specialists. Registrations can be verified free on the AHPRA public register at ahpra.gov.au.

Smile Solutions, Level 1, 220 Collins Street, Manchester Unity Building, Melbourne VIC 3000 — see how to find us. Phone 13 13 96, or theteam@smilesolutions.com.au; full details on the contact page. Monday–Friday 8.00am–6.00pm, Saturday 8.30am–1.30pm, Sunday by appointment.

Published 5 February 2016. General information only; it is not a diagnosis, a treatment plan or a promise of any particular outcome, and it does not replace advice from your treating practitioner. Fees and payment plan terms change; confirm current details with the practice. Payment plan terms are set by the credit provider and change; confirm current terms directly before you commit.

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