In brief
Teeth usually become sensitive when the dentin under the enamel is exposed. Dentin has tiny channels leading toward the nerve, so cold, heat, sweets, acidic foods or even cold air can trigger a short, sharp pain. Common causes are worn enamel, gum recession that exposes the roots, brushing too hard, grinding, acidic foods and drinks, cavities, cracked teeth, worn fillings and recent dental treatment such as whitening. Desensitizing toothpaste helps many people within a few weeks of regular use. If sensitivity is new, getting worse, limited to one tooth or lingers after the cold is gone, see your dentist, because it can signal decay, a crack or a nerve problem.
Key takeaways
- Sensitivity usually means the dentin under the enamel or at the root is exposed.
- Gum recession, enamel wear, hard brushing, grinding and acidic drinks are common causes.
- Desensitizing toothpaste often helps within a few weeks if used consistently.
- Sensitivity in one tooth, or pain that lingers, can signal decay, a crack or nerve inflammation.
- Dentists can treat sensitivity with fluoride, bonding, fillings, gum treatment or, rarely, root canal treatment.
Sensitive teeth are one of the most common dental complaints. The pain is usually short and sharp, triggered by cold drinks, ice cream, hot coffee, sweets or a breath of cold winter air. It is uncomfortable, but it is also a useful signal: something has exposed the inner layer of the tooth.
This guide explains why teeth become sensitive, how to tell everyday sensitivity from a problem that needs attention, what helps at home and how dentists treat it.
What makes a tooth sensitive?
A tooth has three main layers:
- Enamel, the hard outer shell of the crown
- Dentin, the layer underneath, which contains thousands of microscopic channels called tubules
- Pulp, the inner tissue with the nerve and blood supply
Below the gumline, the root is covered by a thin layer called cementum instead of enamel.
When enamel wears away or the gums recede and expose the root, the dentin’s tubules are open to the mouth. Temperature changes, sugar, acid and pressure move the fluid inside those tubules, which stimulates the nerve. That is the sharp twinge you feel.
What are the common causes of sensitive teeth?
| Cause | What happens | Typical pattern |
|---|---|---|
| Gum recession | Gums pull back and expose the root surface | Sensitivity near the gumline, often several teeth |
| Enamel wear (abrasion) | Brushing too hard or using a hard brush wears enamel and roots | Notches near the gumline, often canines and premolars |
| Acid erosion | Acidic drinks, foods or reflux dissolve enamel | Generalized sensitivity, teeth may look glassy or yellow |
| Grinding or clenching | Wear flattens biting edges and can create small cracks | Morning jaw tightness, flattened edges |
| Cavity | Decay breaks through enamel into dentin | One tooth, often sensitive to sweets |
| Cracked tooth | A crack lets stimuli reach the inner tooth | One tooth, pain on biting or release |
| Worn or leaking filling | Gaps form around an older filling | One tooth with an old restoration |
| Gum disease | Inflammation and bone loss expose roots | Bleeding gums, recession, bad breath |
| Recent dental treatment | Whitening, fillings, cleanings or crowns | Usually temporary, settles over days to weeks |
Gum recession and brushing habits
Recession is one of the most common reasons adults develop sensitivity. It can be caused by gum disease, brushing too hard, a hard-bristled brush, grinding, genetics or ageing. Root surfaces are softer than enamel and wear faster, so recession and hard brushing often go together.
Acidic food and drink
Frequent sipping of pop, sports drinks, energy drinks, citrus juice, kombucha or wine bathes teeth in acid. So does acid reflux or frequent vomiting. Over time, acid softens and removes enamel.
Grinding and clenching
Many people grind at night without knowing it. Grinding wears enamel, flattens teeth and can cause small cracks, all of which increase sensitivity. Our guide to night guards for teeth grinding explains the signs and how a guard helps.
Sensitivity or something more serious?
Ordinary dentin sensitivity has a recognizable pattern. Other patterns suggest a different problem.
| Usually sensitivity | Worth a prompt dental visit |
|---|---|
| Short, sharp twinge that stops when the cold is gone | Pain that lingers more than a few seconds after the trigger |
| Several teeth, or both sides | One specific tooth |
| Triggered by cold, sweets, air or brushing | Throbbing pain that starts on its own |
| Stable over time | Getting steadily worse |
| No pain when biting | Pain when you bite down or release |
| No swelling | Swelling, a pimple on the gum or a bad taste |
Lingering or spontaneous pain can mean the nerve is inflamed, which may need root canal treatment. Pain on biting suggests a crack or a problem with a filling, covered in why does my tooth hurt when I bite?. Our article on signs you may need root canal treatment explains the warning signs.
What can you do at home for sensitive teeth?
Use a desensitizing toothpaste
Desensitizing toothpastes work in one of two ways: some calm the nerve’s response, often with potassium nitrate, and others plug the open tubules, using ingredients such as stannous fluoride or arginine. To get the most from them:
- Brush twice a day with it, every day. Most people need a few weeks of regular use.
- After brushing, spit but do not rinse, so the active ingredient stays on the teeth.
- For a particularly sensitive spot, dab a small amount on it before bed.
Brush gently with a soft brush
Use a soft-bristled brush and gentle, small circular strokes. Scrubbing back and forth wears the roots. A power brush with a pressure sensor can help if you tend to press hard.
Watch acidic food and drink
- Have acidic drinks with meals rather than sipping them throughout the day.
- Use a straw for pop and juice, and rinse with water afterward.
- Wait about 30 to 60 minutes after acidic food or drink before brushing, because softened enamel wears more easily.
Check your toothpaste
Some whitening and tartar-control toothpastes are more abrasive or irritating for sensitive teeth. If sensitivity started after a toothpaste change, switch back.
Protect against grinding
If you wake with a sore jaw, headaches or notice worn edges, ask your dentist about a custom night guard.
How do dentists treat sensitive teeth?
The first step is finding the cause. Your dentist will ask when and how the sensitivity happens, examine your teeth and gums, test individual teeth and may take X-rays. Treatment then depends on what is found:
- Fluoride varnish or gel applied in the office strengthens enamel and seals exposed dentin.
- Bonding or a sealant over exposed root surfaces or notches near the gumline.
- Fillings for cavities or to replace a worn or leaking older filling. See our dental fillings page.
- A crown or onlay for a cracked or heavily worn tooth.
- Gum treatment when gum disease is causing recession. Our article on the early signs of gum disease explains what to watch for.
- A gum graft in some cases of significant recession, usually by a gum specialist.
- A night guard if grinding is causing wear.
- Root canal treatment if the nerve is inflamed or infected and sensitivity cannot be controlled another way.
Sensitivity after dental treatment
It is common for teeth to be a little sensitive after:
- Whitening, usually settling within a few days after treatment ends
- A new filling, usually fading over days to a few weeks
- A deep cleaning, while the gums tighten around newly cleaned roots
- A new crown, while the tooth adjusts
Call your dentist if post-treatment sensitivity is getting worse instead of better, lasts more than a few weeks, or comes with pain when biting. Sometimes a filling just needs a small bite adjustment.
How to prevent sensitive teeth
- Brush gently twice a day with a soft brush and fluoride toothpaste.
- Clean between your teeth daily to protect your gums.
- Limit how often you have acidic drinks, and do not sip them all day.
- Wear a night guard if you grind.
- Keep up regular dental exams and cleanings, so recession, wear and decay are caught early.
Sensitive teeth care in Cornwall
At York Street Dental Centre, 118 York Street in Cornwall, we look for the cause of sensitivity before recommending treatment. Sometimes the answer is as simple as a different toothpaste and brushing technique. Other times it is a worn filling, a crack or a gum concern that is better treated early. We explain what we find, your options and estimated fees before any treatment.
We see children, adults and seniors from across Cornwall, including downtown, Riverdale, Eamer’s Corners and Churchill Heights, as well as Lakeview Heights, St. Andrews West and Cornwall Island (Akwesasne). We are accepting new patients, offer direct billing for many insurance plans and welcome eligible CDCP patients.
Book an appointment
Call York Street Dental Centre at (613) 932-1620 or request an appointment online. If your sensitivity is getting worse, lingers or comes with swelling, call us so we can advise how soon you should be seen.
Frequently asked questions
Why did my teeth suddenly become sensitive?
Sudden sensitivity can follow teeth whitening, a new filling or cleaning, a change to a whitening toothpaste, a new cavity, a cracked tooth or gum recession that has just reached the root. If it is limited to one tooth or does not settle in a week or two, have it checked.
How long does desensitizing toothpaste take to work?
Many people notice improvement within a few weeks of brushing with it twice a day. It works best when used consistently. Some people also dab a little on the sensitive area before bed and do not rinse afterward.
Is sensitivity a sign of a cavity?
It can be. A cavity often causes sensitivity to sweets or cold in one specific tooth. Generalized sensitivity across many teeth is more often caused by enamel wear or gum recession. A dental exam and X-rays can tell the difference.
Is it normal for teeth to be sensitive after a filling?
Mild sensitivity after a new filling is common and usually fades over a few days to a few weeks. If it is getting worse, lasts longer, or the tooth hurts when you bite, call your dentist so the bite or filling can be checked.
Can sensitive teeth be fixed permanently?
Often, yes, once the cause is treated. Bonding or a filling can seal exposed areas, gum treatment can protect roots, and changing brushing habits or wearing a night guard can stop further wear. Some people still need a desensitizing toothpaste long term.
Does whitening make teeth sensitive?
It can, temporarily. Sensitivity during or after whitening is common and usually settles once treatment stops. Your dentist can adjust the strength, timing or use a desensitizing product.
When is tooth sensitivity serious?
See a dentist promptly if pain lingers for more than a few seconds after the trigger is gone, throbs on its own, wakes you at night, comes with swelling or affects a tooth that hurts when you bite. These can be signs of nerve inflammation, infection or a crack.
Sources
About the author
This article was written by the York Street Dental Centre Team and reviewed for clinical accuracy by the York Street Dental Centre dental team. York Street Dental Centre is a family dental office at 118 York Street, Cornwall, Ontario K6J 3Y8, providing general, preventive, restorative, and cosmetic dental care for patients of all ages.
Our articles explain common dental questions in plain language, cite reputable health and government sources where relevant, and are updated when guidance changes. Read our editorial policy or learn more about our practice.
This content is intended for general educational purposes and does not replace an examination, diagnosis or personalized treatment recommendation from a dental professional.