What is actually happening inside the tooth
Beneath the enamel lies the dentin, a layer crossed by thousands of tiny channels that lead to the nerve. As long as enamel and gum cover it, the dentin stays sealed off from the outside world.
When that protection thins or recedes, those channels become direct pathways. A sip of cold water, a mouthful of ice cream or a breath of cold air in winter sets the fluid inside the channels moving, and the nerve reacts. This is what is known as dentin hypersensitivity.
That mechanism explains why the pain is typically sharp, brief and triggered by a specific stimulus. It stops as soon as the stimulus is gone.
Why teeth become sensitive
Sensitivity does not happen for no reason. In the vast majority of cases, it comes down to one of these causes.
The gum has receded. Over the years, or in the presence of gum disease, the gum can pull back and expose the root. Unlike the crown of the tooth, the root is not protected by enamel: it becomes sensitive as soon as it is uncovered.
The enamel has thinned. Soft drinks, citrus juices, wine, energy drinks and acid reflux attack enamel through their acidity. This wear is gradual and silent, until the day cold becomes unpleasant.
Brushing is too vigorous. A hard-bristled brush, or good intentions applied horizontally with force, wears away the enamel at the neck of the tooth and pushes the gum back. It is one of the most widespread causes, and one of the easiest to correct.
You clench or grind your teeth. Bruxism, often nocturnal and unconscious, cracks the enamel and overloads the teeth. It frequently comes with a tense jaw on waking or with headaches.
Recent dental work. Whitening, a deep cleaning or a new filling can make a tooth temporarily sensitive. That is expected, and it usually settles within a few days to a few weeks.
A tooth is cracked or decayed. Here, sensitivity is no longer a discomfort: it is a symptom. And this is the case whose signs you need to recognize.
Ordinary sensitivity or warning sign?
The difference lies less in the intensity of the pain than in how it behaves: how long it lasts, what triggers it, and whether it settles on its own.
| Ordinary sensitivity | Have it assessed | |
|---|---|---|
| Duration | A few seconds, then it passes | The pain lingers for several minutes after the stimulus |
| Trigger | Cold, sweet, acidic, cold air | Spontaneous pain, with no trigger at all |
| Timing | During or just after contact | Wakes you at night |
| Extent | Several teeth, often on the same side | A single tooth, always the same one |
| Reaction to heat | Little or no reaction | Heat triggers marked pain |
| On chewing | No pain when biting | Sharp pain when biting or releasing |
| Course | Stable or variable from day to day | Getting worse week by week |
One or two boxes in the right-hand column are enough to justify a call to the clinic.
What these signals may be hiding
Pain that settles in generally indicates that the nerve of the tooth is irritated or inflamed, not simply exposed. The most frequent causes:
- Deep decay. It often progresses without pain, then makes itself felt as it nears the nerve. Treated early, it calls for a simple filling; later, a root canal.
- A crack. A cracked tooth hurts when you release your bite rather than when you bite down. The crack is sometimes invisible to the naked eye and requires an examination to locate.
- Pulpitis. Inflammation of the nerve itself. Heat becomes painful, the pain sometimes spreads to the jaw or the ear, and it does not settle on its own.
- An abscess. If the sensitivity comes with swelling, a persistent bad taste, fever or a swollen lymph node in the neck, this is a dental emergency: call the same day.
In all of these cases, delay works against you. Decay that would have called for a 30-minute filling can become, within a few months, a root canal followed by a crown.
What you can do right now
If your sensitivity stays in the left-hand column of the table, a few adjustments often make a real difference within two to four weeks.
- Change toothpaste. Desensitizing toothpastes gradually block the channels in the dentin. They require daily, consistent use: the effect builds, it is not immediate.
- Switch to soft bristles. And brush in small circular motions rather than scrubbing back and forth. Plaque comes off through movement, not through pressure.
- Wait after acidic foods. Enamel is temporarily softened after citrus, a soft drink or a glass of wine. Brushing right away speeds up the wear. Rinse with water and wait 30 minutes.
- Watch for signs of bruxism. A tense jaw on waking, morning headaches, teeth flattened on top. If that sounds like you, mention it at your next appointment: a night guard is made to measure.
- Breathe through your nose outdoors in winter. A small thing, but the cold air of January is one of the most common triggers in Gatineau.
If nothing changes after a month, or if the pain gets worse in the meantime, stop waiting.
What we can do at the clinic
Treatment depends entirely on the cause, which is why the examination always comes first. Depending on what it reveals:
- Application of a fluoride varnish or a desensitizing agent to the exposed areas, right in the chair. See Preventive Care and Dental Hygiene.
- A sealant or a filling at the neck of the tooth when wear has carved a notch where the tooth meets the gum.
- A night guard to protect the teeth from nocturnal grinding.
- Gum treatment when the recession stems from periodontal disease; a gum graft is sometimes indicated to cover an exposed root.
- A filling or a root canal if decay or a crack is the cause.
An examination with X-rays makes it possible to tell simply exposed dentin from a tooth that needs treatment, a distinction it is impossible to make on your own.
In short
Brief, passing sensitivity can often be managed at home. Pain that lasts, that comes back for no reason, that reacts to heat or that concentrates on a single tooth calls for an examination, and the sooner it is assessed, the simpler the treatment stays.
You do not have to live with a discomfort that makes you avoid ice cream or cold water. The team at Centre dentaire Vadeboncoeur, in the Hull sector of Gatineau, takes the time to find the cause and explain your options.
