Afternoons with Denis Walter

Media item: radio interview

Programme: Afternoons with Denis Walter, 3AW Melbourne

Date broadcast: 27 August 2013

This page records the media item. The audio is the property of the broadcaster and is not reproduced here.

No individual's dental treatment is described here, and section 133 of the National Law prohibits testimonials about clinical care in advertising a regulated health service. What follows is general information on tooth sensitivity — extremely common, widely self-treated, and frequently the wrong thing being treated.

What sensitivity actually is

Dentine is full of microscopic tubules running from the outer surface to the nerve.

When dentine is exposed — because enamel has worn away, or because the gum has receded from the root — fluid inside those tubules moves in response to cold, heat, sweetness, acid or touch. That movement stimulates the nerve. The pain is real and the mechanism is mechanical.

The characteristic pattern of ordinary sensitivity: a sharp, brief pain that starts with the stimulus and stops when the stimulus is removed.

That last detail is the whole diagnostic key, and it is why this page is worth reading before buying anything.

The pattern that means something different

If the pain lingers after the stimulus is gone, wakes you at night, or is worse lying down — that is not ordinary sensitivity.

That pattern suggests irreversible pulpitis — the nerve inside the tooth is inflamed beyond recovery. It does not settle on its own, and desensitising toothpaste will not touch it. It needs assessment, and the treatment is root canal treatment or extraction. See Root Canal Therapy.

Also not ordinary sensitivity:

Sharp pain on biting, or on releasing a bite — the classic sign of a cracked tooth. Frequently missed, and the tooth is savable if caught early.
A tooth tender to touch or to tapping, with a bad taste or a pimple on the gum — an abscess.
Pain in several upper teeth at once, worse bending forward, with a blocked nose — usually sinus, not dental.
Spontaneous pain arriving with no stimulus at all.

Any of those needs examining rather than managing at home.

Why the cause decides the treatment

This is where most self-treatment goes wrong. Sensitivity is a symptom with several different causes, and they are not interchangeable.

Gum recession exposing root surfaces. Root dentine has no enamel over it at all. Causes include brushing too hard with a hard brush, gum disease, and simple age. Recession does not reverse — the management is to stop the cause and desensitise, and occasionally to graft. See Specialist Periodontists.

Acid erosion. Enamel dissolved by dietary acid — soft drinks including sugar-free, sports and energy drinks, citrus, wine, kombucha, fruit and herbal teas — or by stomach acid from reflux, vomiting or an eating disorder. The treatment is to stop the acid. Desensitising toothpaste applied to a mouth that is being acid-washed twice a day achieves very little.

Grinding and clenching. Wears through enamel, flexes teeth and cracks them. A splint protects; it does not stop the grinding. See TMD & Teeth Grinding.

Decay. A cavity is a cause of sensitivity, and it is not going to respond to toothpaste.

A failing or leaking restoration.

After treatment. Sensitivity for a few weeks after a deep filling, a clean, or whitening is normal and usually temporary. Whitening sensitivity in particular is common and settles.

Which is why ‘I have sensitive teeth’ is a starting point, not a diagnosis. The useful appointment establishes which of the above is happening, because the answers differ completely.

What actually works

Desensitising toothpaste, used properly. This is the part people get wrong: it needs to be used consistently for at least two to four weeks, and it works better rubbed onto the sensitive area with a finger and left, rather than brushed and rinsed away. Spit, do not rinse.
Stop rinsing after brushing generally. Leaving concentrated fluoride on the teeth is free and helps.
A soft brush, and less pressure. Sensitivity from over-brushing is common, and brushing harder because it hurts makes it worse.
Reduce acid frequency, and do not brush for at least 30 minutes after anything acidic — an hour is better.
High-fluoride toothpaste, where a practitioner considers it warranted.
In-practice options — fluoride varnish, desensitising agents, sealing exposed root surfaces, bonding, or a splint if grinding is the driver.
Give it time. Genuine dentine hypersensitivity often improves over weeks as the tubules occlude naturally.

What does not help: charcoal or ‘whitening' toothpastes that work by abrasion — they remove enamel, which is the opposite of what a sensitive tooth needs. Nor does avoiding cold indefinitely; that manages the symptom while the cause continues.

When to get it looked at

See a dentist if sensitivity is getting worse, is limited to one tooth, lingers after the stimulus, wakes you at night, comes with pain on biting, or has not improved after a few weeks of doing the right things.

And the standing rule, unrelated but more important than any of the above: any ulcer, white patch, red patch or lump that has not healed in three weeks needs examining.

Common questions

The x-ray showed nothing but the tooth still hurts when I bite. Does that mean there is nothing wrong?

No — and this is the single most useful thing on this page, because an x-ray that looks normal is routinely taken as an all-clear when a crack is the likeliest explanation.

The European Society of Endodontology's 2024 position statement on longitudinal cracks and fractures of teeth reports that the radiographic appearance of a cracked tooth is ‘highly variable', that an early crack may show ‘no obvious signs', and cites work finding that only 2 per cent of cracked teeth with vital pulps had evidence of a crack on a radiograph. A crack runs in the plane of the film; an x-ray is very good at showing decay and bone and very poor at showing a fine split.

Nor does the next scan necessarily settle it. The same statement says CBCT ‘is not predictable in detecting cracks', though it may reveal subtle bone loss alongside one, and notes that vertical root fractures cannot be reliably detected because they are typically only 50 to 100 micrometres wide — finer than the image resolution.

So a crack is diagnosed mainly by what it does, not by what it shows. In a practice-based study of 2,858 cracked teeth across 209 dentists, 45 per cent were symptomatic, with the commonest symptoms pain to cold (37 per cent), biting pain (16 per cent) and spontaneous pain (11 per cent). If your symptom is sharp pain on biting — especially on releasing the bite — say exactly that, say which tooth and what triggers it, and ask whether a crack has been excluded rather than whether the x-ray was clear.

If a crack is found, what actually happens — and what are the odds?

Honest answer: the treatment is less settled than you would expect, and the European Society of Endodontology says so directly — ‘there is no clear evidence on the most suitable restorative treatment approach' for cracked teeth.

What the evidence leans towards is that a crack covered by a restoration that protects the cusps does better than one simply filled. The position statement notes that cracked teeth managed with direct bonded composite restorations ‘may be more likely to require root canal treatment and/or further repair of fractured restorations compared with' those managed with cuspal coverage. That is the argument for an onlay or a crown over a plain filling, and it is a reasonable thing to ask about.

On the nerve, the reported incidence of endodontic intervention after restorative management of a cracked tooth is between 7.7 and 20 per cent — a wide range, which is itself informative. Most cracked teeth restored in time do not go on to need root canal treatment; a meaningful minority do, and nobody can tell you in advance which group you are in.

Two practical consequences. First, a cracked tooth is usually managed in stages, and being told ‘we will restore it and watch the nerve' is a plan rather than an evasion. Second, it is worth asking what the fallback is and what it costs, because the cheaper restoration today can be the more expensive sequence overall.

I grind at night. Will a night guard stop the sensitivity?

It protects the teeth from further wear. It does not stop the grinding, as stated above, and the evidence for splints as a treatment is weaker than their popularity suggests.

Cochrane's 2024 review of occlusal interventions concluded that an occlusal splint ‘may reduce pain in muscles when chewing compared to receiving no treatment, but the results are very uncertain', with ‘little or no evidence that occlusal splints can give other benefits'. The BMJ's 2023 guideline for chronic jaw pain went further and recommended conditionally against reversible occlusal splints, while recommending strongly in favour of supervised jaw exercise and stretching, therapist-assisted mobilisation and cognitive behavioural therapy. It recommended strongly against irreversible oral splints — the kind that permanently alter the bite.

The other thing worth knowing is that thinking about grinding has shifted. A 2025 international consensus concluded that bruxism is not a disorder in otherwise healthy people, may in some circumstances be protective, and retired the old practice of grading it as mild or severe. So grinding by itself is not a diagnosis to be treated; wear, cracks, muscle pain and broken restorations are the things that get managed.

For sensitivity specifically, the guard addresses the cause of further enamel loss while the measures listed above address the exposed dentine you already have. Both, not either.

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.

Every practitioner's registration can be verified free on the AHPRA public register at ahpra.gov.au.

This page records a broadcast and its date, with general information. It is not a diagnosis or a treatment plan, and persistent or worsening pain should be assessed. No individual's clinical information is published here. Third-party broadcast content is not reproduced.

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