Dr. Jahnvi WadhwaBDS, FFAC6 min readIn this article
Tooth sensitivity gets treated as a single problem with a single solution: buy sensitive toothpaste. Sometimes that is right. Often it masks something that needed diagnosing, and the delay makes it worse.
The useful diagnostic question is not "do your teeth hurt?" but "how exactly?"
The diagnostic detail that matters most
Stops within seconds
- Usually exposed dentin, from recession, erosion or a worn area
- Sensitive toothpaste and a technique change are often enough
- Still worth checking if it is localised to one tooth
Lingers 30+ seconds
- Usually an inflamed nerve inside the tooth
- Sensitive toothpaste will not touch this
- Needs an examination, and may need root canal treatment
The common causes
1. Gum recession exposing the root
The crown of your tooth is covered in enamel, which is hard and insulating. The root is not. It is covered in cementum, which is thin and wears away easily. When gums recede, that root surface is exposed and the tubules leading to the nerve are open. Cold air, cold water and sweet things all register sharply.
Recession is usually caused by aggressive horizontal brushing with a hard brush, or by gum disease. Typically felt as a band of sensitivity right at the gum line, often on canines and premolars.
2. Acid erosion
Enamel dissolves in acid. Frequent citrus, fizzy drinks, sports drinks, wine and vinegar-based food thin it over time. So does acid reflux, and so does frequent vomiting, which is why sensitivity in a young patient with a particular pattern of erosion on the inner surfaces of the upper front teeth is something we ask about carefully and privately.
Eroded teeth often look glassy, slightly translucent at the edges, and yellower as dentin shows through.
3. Grinding and clenching
Bruxism wears through enamel on the chewing surfaces and flexes teeth at the gum line, causing enamel to chip away there in a characteristic wedge shape. Most people who grind do it at night and do not know. Clues include morning jaw stiffness, headaches at the temples, teeth that look flattened, and a partner who has mentioned the noise.
4. Decay
A cavity that has passed through enamel into dentin causes sensitivity, classically to sweet things as well as cold. Sensitivity localised to one specific tooth, as opposed to a general sensitivity across several, should always be examined rather than self-treated.
5. A cracked tooth
The signature symptom is sharp pain on releasing a bite rather than on biting down. Crack lines are frequently invisible on X-rays and can be genuinely difficult to locate, but the pattern is distinctive. Cracks matter because they propagate, caught early a crown can hold the tooth together; caught late the crack extends below the gum and the tooth cannot be saved.
6. Irreversible pulp inflammation
When sensitivity to hot lingers for a minute or more, when it wakes you at night, when it throbs, or when cold water briefly relieves it. The nerve is dying. Sensitive toothpaste will not touch this. It needs root canal treatment.
Sensitivity right after dental treatment
Worth separating out, because it is usually normal. Sensitivity for a few days after a filling, a few days after scaling, or a few days after whitening is expected and settles. What is not normal is sensitivity that is worsening after a week, or pain on biting that persists, which often just means the filling is fractionally high and needs a two-minute adjustment. Come back rather than waiting it out.
What actually helps
Get it diagnosed if localised, lingering or worsening
Everything below assumes generalised sensitivity from exposed dentin.
Use a desensitising toothpaste properly
Most people use it wrong. Rub a small amount directly onto the sensitive area with a fingertip and leave it, rather than brushing and immediately rinsing it away. Do this last thing at night.
Spit, don't rinse, after brushing
Rinsing washes away the fluoride and the active ingredient before they have done anything.
Switch to a soft brush, stop scrubbing horizontally
Small circles, angled into the gum line, light pressure. If your bristles splay within a month, you are pressing far too hard.
Do not brush straight after anything acidic
Enamel is temporarily softened; brushing then physically removes it. Wait an hour, or rinse with plain water.
Drink acidic drinks with a meal, not across the day
Use a straw where practical.
Ask about a night guard if you grind
It is the only thing that reliably protects teeth from bruxism.
Fluoride varnish in the clinic
Can settle stubborn areas quickly.
Frequently asked
Two to four weeks of consistent use. If there is no improvement at all after a month, the cause is probably not simple exposed dentin and needs examining.
Not necessarily. Most sensitivity is exposed dentin rather than decay. But sensitivity concentrated on one tooth, or triggered by sweet things specifically, makes decay much more likely and is worth checking.
Not spontaneously. The recession can be stopped from progressing by correcting brushing technique and treating gum disease, and grafting can cover exposed roots in selected cases. Prevention is far more effective than repair here.
Cold air moving across exposed dentin triggers the same fluid movement in the tubules that cold water does. It is a common presentation of recession or erosion, and it responds to the same measures.