What in Dentin Hypersensitivity ?

Exaggerated response of the tooth to hot, cold or stream of air can be described as dentin hypersensitivity of the tooth. The exogenous stimuli may include thermal, tactile or osmotic changes. While extreme stimuli can make all the teeth hurt, the term hypersensitivity means painful response to stimuli not normally associated with pain. 

Dentin hypersensitivity is defined as “sharp, short pain arising from exposed dentin in response to stimuli typically thermal, chemical, tactile or osmotic and which cannot be ascribed to any other form of dental defect or pathology” 

The dental pulp is richly innervated with nerves and blood vessels. The nerve group present are the A delta fibres and C fibres majorly. The sharp, better localized pain is mediated by A delta fibers, C fiber activation is connected with the dull radiating pain sensation. Myelinated A fiber are responsible for dentin sensitivity. Tooth hypersensitivity differs from dentinal or pulpal pain. In case of dentin hypersensitivity, patient’s ability to locate the source of pain is very good, whereas in case of pulpal pain, it is very poor 

Theories of dentin hypersensitivity 

• Neural theory 
• Odontoblastic transduction theory 
• Hydrodynamic theory 

The most accepted theory is the Brannstorm’s hydrodynamic theory which says that displacement of the dentinal tubule contents is rapid enough to deform nerve fiber in pulp or predentin or damage odontoblast cell. This rapid fluid movement activates the mechanoreceptor nerves of A group in the pulp and cause dentinal hypersensitivity.

Causes 

The primary underlying cause for dentin hypersensitivity is exposed dentinal tubules which can occur either by loss of covering periodontal structures (gingival recession), or by loss of enamel.

Common reasons for gingival recession  

• Inadequate attached gingiva 
• Toothbrush abrasion 
• Oral habits resulting in gingiva laceration, i.e. traumatic tooth picking, eating hard foods 
• Excessive tooth cleaning 
• Gingival recession secondary to specific diseases 
• Crown preparation 

Reasons for continued dentinal tubular exposure 

• Poor plaque control, i.e. acidic bacterial byproducts 
• Excess oral acids, i.e. soda, fruit juice, swimming pool chlorine, bulimia 
• Cervical decay 
• Toothbrush abrasion 

Causes of loss of enamel 

• Attrition by exaggerated occlusal functions like bruxism 
• Abrasion from dietary components or improper brushing technique 
• Erosion associated with environmental or dietary components particularly acids 

Management

Home care with dentifrices 

• Potassium nitrate dentifrices  
• Fluoride dentifrices. 

In office treatment procedure 

• Varnishes 

Treatments that partially obturate dentinal tubules 

• Burnishing of dentin  
• Silver nitrate 
• Zinc chloride—potassium ferrocyanide  
• Calcium compounds. 
• Fluoride compounds 
• Iontophoresis 
• Strontium chloride 
• Potassium oxalate. 

Tubule sealant 

• Restorative resins 
• Dentin bonding agents. 

Miscellaneous  

• Laser 
• Patient education 
• Dietary counseling 
• Modification of tooth brushing technique  
• Plaque control 

 Article by Dr. Siri P.B.