There are many reasons that one or more teeth can be sensitive. It is important to see a dentist if you have a tooth that is sensitive to cold, hot or sweet foods or drinks. This may be a sign of conditions such as tooth decay or tooth erosion. It is important to make sure there is no tooth decay or other conditions that are making the teeth sensitive.
Symptoms
Tooth sensitivity will often feel like a short, sharp pain when the tooth is being exposed to a stimulus. Stimulus that can cause pain in sensitive teeth include:
- hot foods or drinks
- cold foods or drinks
- cool air
- gentle touch, for example from a toothbrush
The sensitivity will often go away when the stimulus is removed. Pain or discomfort that is still present after the stimulus has been removed may be a sign of tooth decay. It is important to see a dentist to ensure tooth decay or tooth erosion is not the cause of the tooth sensitivity.
Sensitivity can occur in only one or two teeth, or it can affect multiple teeth.
Causes
There are many reasons teeth can become sensitive. Some common causes include:
- Tooth erosion due to regularly eating or drinking acidic foods and drinks.
- Teeth grinding or clenching teeth at night whilst sleeping.
- Developmental conditions that affect the teeth causing weakened tooth structure, for example enamel hypoplasia.
Teeth can sometimes experience sensitivity after dental treatment. This is usually temporary and should subside after a few days but may last for one or two weeks. It can occur after treatments such as a professional teeth clean (known as a scale and clean), fillings, crowns and teeth whitening. If the sensitivity continues or turns into pain, return to see your dentist.
How sensitivity occurs
For teeth that are not affected by conditions such as tooth decay, they typically become sensitive due to loss or wearing away of the outer protective layers of the tooth. Tooth enamel protects the part of the tooth we see inside the mouth, called the crown. The surface of the tooth root/s are protected by a layer of tooth structure called cementum. These protective outer layers do not have a nerve supply or feeling. They protect the inside layer of the tooth, known as dentine, which is made up of thousands of tiny tubules or canals that connect with the dental pulp at the centre of the tooth. The nerves are found inside the dental pulp and they branch out to sit inside the dentine tubules.
Tooth sensitivity can occur when the dentine becomes exposed when the overlying tooth enamel or cementum are worn away. Cementum can become exposed when the gums shrink away to expose part of the tooth root. The gum shrinking away is referred to as gum recession and it can be caused by several factors, including gum disease.
Cementum is not as strong as tooth enamel and can wear away more easily. When the dentine layer is exposed, sensitivity can occur as the dentine tubules and the nerves inside are stimulated. This may be diagnosed as ‘dentine hypersensitivity’. It is one of the most common complaints from patients attending dental clinics.
The below image closely shows the tiny channels, known as dentine tubules, inside the dentine that connect to the dental pulp.
Management
It is important to see your dentist for a check-up. They will examine the teeth and determine the cause of the tooth sensitivity so that they know how best to treat it. At your appointment, your dentist may discuss your eating, drinking and oral hygiene habits. It is important for them to be aware of lifestyle factors such as regularly drinking soft drinks, which may be contributing to your sensitive teeth.
Dental treatment
If the tooth sensitivity is due to tooth decay or fillings already present in the tooth starting to break down, this needs to be treated. After treatment, the sensitivity should subside. If these issues are not treated, the sensitivity may worsen and may turn into pain.
Sensitive teeth with exposed dentine may be treated by placing a covering over the exposure site. This covering could be a thin filling or a layer of fluoride gel. This fluoride is stronger than your daily toothpaste and the application of this gel has been shown to help with dentine sensitivity.
Toothpaste
Toothpastes can be purchased for the specific purpose of treating sensitive teeth. These are called desensitizing toothpastes. Ingredients that help to treat tooth sensitivity work by two main methods.
- The nerves in the teeth are soothed so they are not triggered by stimuli.
- A barrier is created over the sensitive area stopping it from responding to stimuli.
Ingredients included in desensitizing toothpaste for the purpose of reducing dentine sensitivity include potassium nitrate, arginine and calcium carbonate, strontium chloride, stannous fluoride, and calcium sodium phosphosilicate.
If tooth decay has developed and is causing sensitivity, using desensitizing toothpaste will not treat the decay, this must be done by a dentist.
Prevention
Good oral hygiene is your best defence against tooth sensitivity.
- Keep good oral hygiene by brushing twice per day with fluoride toothpaste and flossing at least once per day.
- Do not apply too much pressure when brushing your teeth.
- Limit the amount of sugary or acidic drinks you consume, and do not brush your teeth straight after. Try to wait at least 60 minutes before doing so. Brushing too soon can lead to increased tooth wear.
Choose to drink plain tap water to stay hydrated. Adding citrus fruit, such as lemon, to your water and sipping it throughout the day can lead to tooth erosion and/or tooth sensitivity.
Written by the Australian Dental Association
