Dentin hypersensitivity is defined as a feeling of sensitivity inside the tooth surface when it is exposed to thermal (heat or cold), chemical and tactile (pressure or movement) stimuli. Therefore it is commonly known as sensitive teeth. It is marked by sharp pain that lasts for a few seconds. The pain is usually felt when drinking cold water or consuming candy or sweet foods. The condition is very common and is caused by tiny canals that form in the tooth thereby exposing inner tissue to the mouth environment.
The visible portion of teeth, known as the crown, is composed of three layers – enamel, dentin and pulp. Enamel does not have a nerve supply. The nerve supply of the tooth lies inside the pulp but some nerve fibers are located in dentin. The nerve fibers present inside dentin, when stimulated or irritated, are responsible for dentin hypersensitivity.
Dentin hypersensitivity most commonly affects the lower third region of the teeth. Canines are more commonly affected followed by premolars incisors and molars. The patient experiences sharp shooting pain of a short duration in response to hot, cold, sweet or sour food or drinks. The pain may also be felt on pressure, touch or biting.
The pain is temporary and eases as soon as the stimulus is removed. Sensitive teeth pain can be mild to moderate in intensity. In some cases there may not be any pain, only a feeling of numbness or irritation.
The lower third of the tooth may show a crescent moon shaped notch due to wearing down of the enamel. In cases with enamel wear due to improper biting, the cusps of the teeth become flat and loose their sharpness. On observation, the affected teeth may show receded gums. Faulty, leaky dental restorations may be visible in the mouth cavity.
Dentin hypersensitivity is a condition commonly seen in adults. Loss of surface enamel is the primary cause of dentin hypersensitivity. The following factors are responsible for this loss of enamel thereby leading to dentin hypersensitivity.
- Grinding of teeth
- Improper tooth brushing techniques
- Using a toothbrush with very hard bristles
- Excessive consumption of acidic beverages
- Receding gums
- Ongoing periodontal treatment
- Faulty dental restorations
- Gastroesophageal reflux disease (GERD)
Dentin hypersensitivity can be treated by various measures. Dietary counseling involves minimizing the consumption of acidic beverages is one of the ways to limit the condition. The other preventive measures include correcting faulty brushing techniques and seeking treatment of faulty restorations or crowns.
Desensitization of nerve fibers in dentin can be carried out using potassium nitrate, calcium hydroxide or calcium phosphate tooth pastes. These substances cause mineralization of the dental tubules making them less permeable to entry of fluids from oral cavity. Other chemicals used in treating dentin hypersensitivity are potassium oxalate and strontium chloride.
The use of fluoridated toothpastes and mouth rinses is recommended to promote re-mineralization of enamel. In dental clinics, application of topical fluorides can be done using special fluoride trays and solutions. The other treatments carried out in dental clinics include use of dental varnishes and dental adhesives. If the teeth do not respond to initial treatments, restoration can be done using dental composites or dental cements.