A sudden sharp sensation while drinking cold water or eating something sweet can be uncomfortable. For some people, it happens occasionally. For others, even brushing or breathing in cold air can trigger discomfort.

This condition is commonly called tooth sensitivity. Although it is often related to exposed dentine, sensitivity can also be a sign of cavities, cracks or other dental problems.

What is tooth sensitivity?

Tooth sensitivity, also known as dentine hypersensitivity when its characteristic criteria are met, is a short, sharp pain arising from exposed dentine in response to stimuli such as cold, heat, touch, air or sweet and acidic substances.

Dentine is the layer beneath the hard outer enamel of the crown and cementum covering the root. It contains microscopic tubules that communicate with the pulp. When dentine becomes exposed and the tubules are open, external stimuli can trigger pain.

What causes tooth sensitivity?

Several factors can expose dentine, wear down protective tooth structure or irritate the dental pulp.

1. Gum recession

When the gum moves away from the tooth, the root surface may become exposed. Unlike the crown, the root is not covered by enamel. Exposed root dentine can therefore become sensitive to cold, touch and brushing.

2. Enamel erosion

Frequent exposure to acidic foods and drinks, such as citrus fruits, soft drinks and acidic beverages, can gradually soften and wear away enamel. Once the protective layer becomes thinner, sensitivity may develop.

3. Aggressive tooth brushing

Brushing with excessive force or using an abrasive toothpaste may contribute to tooth wear and gum recession. A soft-bristled toothbrush and gentle brushing technique can help protect your teeth.

4. Tooth decay

Cavities can cause sensitivity to cold, sweets and other stimuli. As decay progresses deeper into the tooth, symptoms may become more persistent or painful.

5. Cracked or fractured teeth

Small cracks can produce discomfort during chewing or when releasing biting pressure. The pain may be difficult to locate and can sometimes resemble ordinary sensitivity.

6. Teeth grinding and clenching

Repeated excessive forces can cause wear, cracks and stress on teeth. Some people with bruxism also experience sensitivity or discomfort in their teeth and jaw muscles.

7. Recent dental procedures

Temporary sensitivity may occur after procedures such as professional cleaning, fillings, crown preparation or teeth whitening. The duration and severity depend on the procedure and the condition of the tooth.

Why do sensitive teeth react to cold water?

One widely accepted explanation is the hydrodynamic theory. Dentine contains tiny fluid-filled tubules. When dentine is exposed, stimuli such as cold air, cold drinks or touch can cause movement of fluid within these tubules.

This fluid movement can stimulate nerve endings associated with the dental pulp, producing a brief, sharp sensation.

This is why exposed dentine can react suddenly to cold water or even a stream of air.

What are the symptoms of sensitive teeth?

Common symptoms include:

• Sharp, brief pain when drinking cold water.
• Discomfort while eating ice cream or cold foods.
• Sensitivity to hot, sweet or acidic foods.
• Pain when brushing or touching exposed root surfaces.
• Discomfort when cold air reaches the teeth.

Typical dentine hypersensitivity produces brief pain that settles shortly after the stimulus is removed. Pain that lingers, occurs spontaneously or wakes you at night needs further investigation.

How is tooth sensitivity treated?

Treatment depends on the underlying cause. Your dentist will examine the teeth and gums, identify the sensitive area and determine whether the problem is exposed dentine or another dental condition.

1. Desensitising toothpaste

Desensitising toothpastes contain ingredients that help reduce sensitivity. Depending on the formulation, they may reduce nerve response or help occlude dentinal tubules.

Ingredients used in sensitivity toothpastes include potassium salts, stannous fluoride and other desensitising or tubule-occluding agents. Regular use as directed is important; relief may take several applications or weeks.

2. Fluoride application

Professional fluoride treatments may help strengthen susceptible tooth surfaces and reduce sensitivity in selected cases. Your dentist will choose an appropriate product and application method.

3. Desensitising agents in the dental clinic

Your dentist may apply professional desensitising agents or materials to exposed dentine. These can help reduce fluid movement through dentinal tubules and relieve symptoms.

4. Composite restoration or bonding

If sensitivity is associated with a localised area of exposed dentine, a cervical defect or structural damage, a suitable restorative material may be used to cover and protect the affected area.

5. Treatment of gum recession

When root exposure is associated with gum recession, treatment depends on the cause, periodontal condition and amount of tissue available. Selected cases may benefit from periodontal procedures such as root coverage surgery.

6. Treatment for decay or cracked teeth

If sensitivity is caused by a cavity or cracked tooth, the tooth may require a filling, an appropriate protective restoration or other treatment depending on the extent of damage.

7. Root canal treatment in selected cases

If the dental pulp is irreversibly inflamed or infected, root canal treatment may be necessary. This is not a routine treatment for ordinary dentine hypersensitivity; it is considered only when the diagnosis supports it.

How can you prevent tooth sensitivity at home?

Simple changes in your daily oral-care routine can help reduce sensitivity and protect your teeth.

• Use a soft-bristled toothbrush.
• Brush gently with a fluoride toothpaste twice daily.
• Consider a desensitising toothpaste if recommended by your dentist.
• Avoid brushing immediately after consuming acidic foods or drinks; rinse with water and allow time for saliva to neutralise acids.
• Reduce frequent consumption of acidic drinks and foods.
• Avoid brushing with excessive force.
• Do not use abrasive home remedies such as charcoal or aggressive whitening powders.
• Wear a professionally recommended night guard if you grind your teeth.
• Attend regular dental check-ups.

When should you visit a dentist?

Occasional mild sensitivity may improve with appropriate home care, but persistent or unexplained symptoms should be assessed.

Arrange a dental examination if you notice:

• Sensitivity that continues or becomes more severe.
• Pain that lingers after drinking cold or hot liquids.
• Spontaneous toothache without an obvious trigger.
• Pain while biting or chewing.
• A visible cavity, crack or broken filling.
• Swelling around a tooth or gum.

Facial swelling accompanied by fever or difficulty swallowing or breathing requires urgent medical attention.

Frequently asked questions

Final thoughts

Tooth sensitivity is common, but it should not be ignored when it persists or affects your daily activities. Identifying the underlying cause is the most important step towards effective treatment.

With appropriate oral hygiene, suitable desensitising products and professional dental care, many cases of tooth sensitivity can be successfully managed.

This article is for general patient education and does not replace a clinical examination, diagnosis or individual treatment advice.