Sensitive Teeth: Why They Hurt and How to Stop It

📖 11 min read  ·  Updated 24/08/2026

What are sensitive teeth, exactly?

If a mouthful of iced water, a spoon of ice cream or a sudden breath of cold winter air makes you wince, you have sensitive teeth — what dentists call dentine hypersensitivity. It is one of the most common dental complaints in Australia, and estimates of how many adults it affects vary widely, from roughly one in eight upward depending on how it is measured (West and colleagues, Journal of Dentistry, 2013).

The pain has a very specific signature: it is sharp, sudden and short. It arrives the instant a trigger hits the tooth and it fades within seconds once the trigger is gone. That is the hallmark of true sensitivity — and, importantly, it is the feature that separates it from the deeper, lingering ache of decay or a dying nerve.

The one-sentence cause: exposed dentine

Every case of sensitive teeth traces back to the same thing — exposed dentine. Your tooth has three layers: hard enamel on the crown, a tough root covering called cementum below the gum, and underneath both a living layer called dentine. Dentine is honeycombed with thousands of microscopic channels, the dentinal tubules, and every one of them runs inward toward the nerve.

While enamel and gum sit over the dentine, those tubules are sealed off and you feel nothing. The moment the enamel wears thin or the gum recedes and the softer dentine is left bare, the tubules are open to the mouth. This is the accepted explanation for tooth sensitivity — the hydrodynamic theory first described by Brännström: fluid inside the tubules moves when a cold or sweet stimulus hits, and that tiny movement is enough to set off the nerve.

What triggers the pain?

Sensitive teeth do not hurt all the time. They react to specific triggers that can move fluid inside the open tubules. The most common ones:

If your pain is set off mainly by cold, that is a reassuring sign — cold-triggered, short-lived pain is the textbook picture of ordinary sensitivity. We break down that specific symptom in why cold water hurts your teeth.

Why did my dentine get exposed?

Sensitive teeth are a symptom, not a diagnosis. The useful question is why the protective layer wore back. There are five common routes, and most people have more than one working at once.

1. Gum recession

The single biggest cause. When gums recede they uncover the root, which has no enamel — only a thin, quickly-worn layer of cementum over bare dentine. Recession is driven by hard brushing, gum inflammation and age. What can and cannot be recovered is covered in receding gums: what can be reversed.

2. Enamel erosion (acid)

Repeated acid attacks from soft drink, citrus, wine, sports drinks and reflux dissolve enamel from the crown down. Erosion is chemical wear, and unlike a cavity it spreads across broad, smooth surfaces — often the first sign is generalised sensitivity across several teeth at once.

3. Abrasion (over-brushing)

Scrubbing hard, especially with a stiff brush and a side-to-side sawing motion, physically grinds a notch into the tooth at the gum line and wears the gum back at the same time. It is one of the few causes of sensitive teeth that is entirely self-inflicted — and entirely preventable.

4. Grinding and clenching (bruxism)

Night-time grinding flexes the tooth and is thought to crack tiny flakes of enamel away at the neck of the tooth, exposing dentine. Grinders often wake with sensitivity and a tight jaw.

5. A cracked tooth or worn filling

A hairline crack or a filling that has pulled away from the tooth opens a direct path to the dentine. This one behaves differently — see the red-flag section below.

Is it sensitive teeth, or something worse?

Most sensitivity is harmless. But the same nerve that gives a harmless cold-jolt also warns you about decay and cracks, so it is worth knowing the difference. Use the pain's timing as your guide.

How do you actually stop sensitive teeth?

There are only two mechanisms that genuinely work, and the best approach uses both at once:

Occlusion is the more durable fix because it treats the cause — a sealed tubule cannot transmit anything. The nerve-calming route works from the other end and is why many desensitising formulas pair an occluding agent with a potassium salt. A Cochrane review of potassium-containing toothpastes found they can reduce sensitivity, and occluding agents such as hydroxyapatite have been shown to physically close exposed tubules under the microscope.

Alongside the toothpaste, a handful of habits do the heavy lifting:

The toothpaste question: what to look for

A desensitising toothpaste is the backbone of home treatment, but they are not all the same. The two things that matter are whether it occludes, whether it calms the nerve — and ideally it does both while also delivering fluoride. Read the active-ingredient panel, not the front of the box; our guide to telling sensitivity from receding gums walks through what the two feel like.

This is where LACALUT SENSITIVE is deliberately built. The toothpaste carries hydroxyapatite — the same mineral your enamel is made of — which occludes the exposed dentine tubules and remineralises the worn surface, plus 1,488 ppm fluoride to harden the enamel and a mild astringent. Paired with it, the LACALUT SENSITIVE mouthwash adds arginine and potassium chloride: arginine helps plug the tubules while potassium settles the nerve — the two mechanisms in one rinse.

Habits that quietly make sensitive teeth worse

Plenty of well-meant routines backfire. If you have sensitive teeth, these are the ones to drop:

Sensitivity that flares straight after a scale-and-clean is usually short-lived and settles on its own — we cover that specific case in sensitive teeth after a dental clean.

How long until sensitive teeth settle down?

With a proper desensitising toothpaste used twice every day, most people notice a clear improvement within two to four weeks. Occlusion is cumulative — each brush lays down a little more mineral in the tubules — so consistency matters far more than brushing hard. The single most common reason a desensitising toothpaste 'does not work' is stopping too soon or only using it now and then.

When sensitive teeth will not go away

If you have used a desensitising toothpaste correctly for a month and there is no change — or the pain is getting worse, lingering, or centred on one tooth — stop self-treating and see a dentist. Sensitivity that resists home care can mean a cavity, a cracked tooth, an exposed nerve or a failing filling, and those need professional treatment. Home desensitisers manage the broad, cold-triggered kind; they are NOT a fix for structural damage.

Medical disclaimer: This article is for general information only and does not constitute dental or medical advice. Consult a registered dental practitioner for assessment.

Sensitive teeth: frequently asked questions