Throughout your dental education and career, you will no doubt come across dentin hypersensitivity often. In this article, we explore the causes of this very common condition and consider why some people are more susceptible to sensitivity than others. We also discuss the current best-practice methods for diagnosing and treating dentin hypersensitivity in your patients.
What is dentin hypersensitivity?
Dentin hypersensitivity is defined as a short, sharp pain resulting from exposed dentin, in particular open dentin tubules, in response to a particular stimulus and which cannot be explained by another oral health condition or disease, e.g., dental caries. The dentin tubules are narrow, fluid-filled channels leading to the dental pulp. Dentinal hypersensitivity is believed to result from movement of the fluid within the dentinal tubules, stimulating the nerves and leading to the characteristic pain of dentin hypersensitivity in the presence of stimuli.
Common stimuli include:
Hot or cold foods or drinks
Cold air
Acidic or sugary foods or drinks
Touch or pressure, e.g., toothbrushing.
What makes some people more susceptible to sensitivity?
Up to 57% of patients are reported to suffer from dentin hypersensitivity, but some are more susceptible than others. One finding has been that individuals with sensitivity had more dentin tubules than others.
Dentin becomes exposed when the enamel and/or cementum covering it lost. The causes of enamel loss include:
Attrition, commonly caused by bruxism (teeth grinding).
Abrasion, often caused by overly aggressive toothbrushing.
Erosion from non-bacterial acids.
Abrasion and erosion also cause cementum to be lost.
Erosion is a common cause of enamel loss, the result of exposure to extrinsic acids (typically due to repeated consumption acidic foods and drinks) and gastric acid present intraorally due to repeated vomiting or Gastro-Esophageal Reflux Disease (GERD). Initially, these acids cause a loss of minerals from the surface of the tooth enamel (demineralization) which softens it. Enamel is lost later in the process once the enamel is soft. Saliva buffers the intraoral pH, helping to prevent or limit a damaging decrease in pH and salivary proteins are also protective against erosion. Together, these provide the protective benefit of saliva. Saliva also supplies calcium and phosphate for remineralization, however this process is limited for erosion. A net loss of minerals over time with repeated excessive acid exposure results in erosion progressing to irreversible enamel loss. Cementum is not as strong or thick as enamel. That means that if root surfaces are exposed, erosion can progress quickly to complete loss of the exposed cementum.
How is dentin hypersensitivity diagnosed?
Despite the high prevalence of dentin hypersensitivity, many sufferers accept sensitive teeth as a fact of life and do not seek treatment. For that reason, it is good practice to proactively initiate a discussion with your patients at each appointment.
When patients report sensitivity, the first step is to get an accurate picture of their pain. You might ask questions like:
When did the pain start?
Can you describe the pain, e.g., short, sharp, stabbing, throbbing?
Does anything in particular trigger the pain?
Does anything help to relieve the pain?
How long does the pain last?
- How intense is the pain?
Since patients do not always report sensitivity, it is also important to ask probing exploratory questions that might open up a discussion.
Next, you will discuss the patient’s medical history, oral health habits and lifestyle behaviors to identify risk factors, and conduct a clinical exam. Dentin hypersensitivity is a diagnosis of exclusion, so you first need to perform a differential diagnoses, and rule out other conditions such as dental caries.
As part of the clinical exam, you might try to reproduce the patient’s pain. For example, you can use hot/cold water to replicate a thermal trigger, or a dental explorer to replicate tactile stimulation. Not only does this help to confirm the link, but it helps you to measure the severity and compose an appropriate treatment plan.
Pain is a subjective experience and can vary greatly from person to person. However, there are objective measures we can use to quantify pain. One such tool is the Visual Analog Scale (VAS), which asks the patient to indicate their pain on a 10 cm continuum. 0 cm indicates no pain, while >5 cm is considered to represent pain. If the patient reports sensitivity to cold air specifically, you may use the Schiff Cold Air Sensitivity Scale to measure their reaction to a blast of cold air.
How is dentin hypersensitivity treated?
When a diagnosis of dental hypersensitivity has been reached, treatment can be provided. Treatment for dentinal hypersensitivity can be provided using in-office and/or home use products. These work in one of two ways, either by occluding the dentinal tubules which then prevents movement of tubular fluid or with use of a depolarizing agent that prevents the transmission of pain signals.
For in-office treatment, you can apply a 5% sodium fluoride varnish (22,600 ppm fluoride) such as Colgate PreviDent Varnish which provides immediate and lasting relief from sensitivity following its application. Another in-office option, in this case for use to relieve sensitivity prior to patient care (e.g., to prevent pain when the air-water syringe is used), is Anywhere Anytime Sensitivity Relief Serum. This contains Pro-Argin technology which incorporates arginine bicarbonate and calcium carbonate for occlusion of the dentinal tubules. Sensitivity relief is rapidly obtained after applying the gel directly to a sensitive tooth with your gloved fingertip and gently massaging the area for 1 minute. The patient can be given the remainder of the tube to use for sensitivity relief at home. The same Pro-Argin technology is available in Europe in a desensitizing toothpaste for home care.
Dentinal hypersensitivity is frequently managed at home, with the use of anti-sensitivity fluoride toothpastes or potassium nitrate toothpastes. Stannous fluoride, and amine fluoride (available in Europe), provide sensitivity relief by occluding the dentin tubules. Colgate Total toothpaste contains stannous fluoride, and intraorally the stannous (tin) ion forms tin-rich compounds that occlude open dentinal tubules and deposit a tin-rich layer over the surface of the tooth. Potassium nitrate is a depolarizing agent that reaches the nerve and prevents transmission of pain signals to the brain. Colgate Sensitive toothpaste contains both potassium nitrate to provide long-lasting sensitivity relief with continued use and sodium fluoride to help protect against dental caries.
it is important to also coach patients on oral care and to help eliminate any contributing causes. For example, a patient may require:
Dietary counselling to minimize extrinsic acids; and/or
Referral to a physician in cases of relevant conditions associated with repeated vomiting, e.g., bulimia.
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