Dentine hypersensitivity, or tooth sensitivity, is characterised by a short, sharp pain arising from exposed dentine in response to stimuli (typically thermal, evaporative, tactile, osmotic or chemical) which cannot be ascribed to any other form of dental defect or pathology.It can also manifest as a dull, throbbing ache.Despite its name, dentine hypersensitivity does not indicate sensitivity of the dentine – which does not feel pain or sensitivity – but the response of the pulp nerves to stimuli at the site of the dentine surface.
Many theories exist regarding the mechanism by which dentine hypersensitivity occurs, but the hydrodynamic theory is the most widely accepted. The hydrodynamic theory holds that, when an appropriate stimulus is applied to dentine, a change in the movement of fluid within the dentinal tubules results, creating a pressure change in the dentine and triggering a response in the pulp nerves, ultimately causing pain for the patient.
How common is dentine hypersensitivity, and who is at risk?
More than 1 in 3 adults suffer the pain of dentine hypersensitivity. Some studies estimate that as many as 57% of patients experience dentine hypersensitivity symptoms. However over half of sufferers endure these symptoms in silence and fail to seek appropriate help from their dentist. Sufferers are frequently aged between 20 and 50 years old, with women more likely to experience symptoms than men and a peak in incidences occurring at the end of the third decade.
Dentine hypersensitivity occurs most frequently on the buccal cervical regions of teeth, and most commonly affects the canines and first premolars above the incisors, second premolars and molars. Teeth with lower plaque scores are associated with the condition, suggesting a connection between regular (possibly over-zealous) toothbrushing and the onset of sensitivity.
The condition may be brought about by enamel loss as a result of tooth wear, and by the concomitant exposure of dentine. Acid wear, abrasion and attrition are all associated with the loss of enamel, and so with the onset of dentine hypersensitivity. Acid wear however has been identified as the current primary cause of tooth wear,5 and as such a leading factor in the development of tooth sensitivity.
Gingival recession is also associated with the development of dentine hypersensitivity, since the root surface exposure which follows recession can result in a loss of cementum and subsequently in the exposure of the dentinal tubules.
What are the signs and symptoms of dentine hypersensitivity, and how is it diagnosed?
There are a number of other conditions which cause similar pain to the patient, including:
- Chipped teeth
- Fractured restorations
- Cracked tooth syndrome
- Tooth bleaching procedures
- Pulpal response to caries and restorative treatment
Identification of dentine hypersensitivity should therefore be made through differential diagnosis.The defining symptom of dentine hypersensitivity is pain and sensitivity when teeth are exposed to an external stimulus.
Pain scores may be measured along a visual analogue scale and used to determine the progress or deterioration of the patient’s condition over several visits.