Why do I get Pain From Cold?

The hydrodynamic theory is the most accepted explanation for tooth sensitivity.

Brännström, in 1966, suggested that dentine hypersensitivity is due to the abrupt movement of fluid within the dentinal tubules. This fluid flow may be triggered by thermal stimuli (hot or cold), osmotic stimuli (sugary foods), mechanical stimuli (chewing), or evaporative stimuli (air). The movement of dentinal fluid leads to mechanical deformation and activation of low-threshold A-delta fibres located in close contact with odontoblasts. Basically you have small tubules that are normal micro holes in the second layer of your tooth like a spongy cake. These small tubules are a passage that fluid can move through from the the nerve to the outside environment. The dentine tubules are not usually exposed to the outside environment while your young. That is why you tend to get this sharp pain to cold drinks, air and sweets as you get older. This is usually due to dentinal tubules being exposed due to recession of the gums, or wearing down of the enamel layer due to brushing, attrition or erosion.

Treatment

In terms of management the causing factors should be addressed first to prevent further progression. This can be tooth brushing technique, gum disease and erosive agents.Once the causing factors have been addressed then the pain/symptoms management can be done. The management of which varies between patients and situation.




Usually the first line of treatment for dentine hypersensitivity is desensitising toothpastes. Toothpastes that are aimed at relieving sensitivity work through various mechanisms. Multiple toothpastes may need to be trailed before an effective solution is found. Sensitivity toothpastes may be applied with a finger for symptomatic relief throughout the day without the need to brush. The key with these toothpastes is to build up a coating over time and making sure you do not wash during or after brushing. Otherwise, you’re washing away the toothpaste and decreasing the coating.

• Colgate Sensitive Pro-Relief contains arginine and calcium carbonate. These ingredients occlude the dentinal tubules by forming a positive complex with the negatively charged dentinal surface.
• Sensodyne Pronamel contains potassium nitrate. This ingredient is suggested to depolarise nerve fibres within the dentinal tubules. Some literature reports no improvement of symptoms with use while others report improvement after 2 weeks.
• Sensodyne Original contains strontium which occludes tubules to some extent. In a literature review, only one study described strontium acetate as being more efficacious than calcium carbonate and arginine; overall review favours arginine and calcium carbonate.
• Sensodyne Complete Protection contains calcium sodium phosphosilicate. This ingredient is designed to occlude tubules and stimulate remineralisation. Efficacy is proven but seems inferior to arginine and calcium carbonate.




Your Oral Health Practitioner may use professional application of fluoride or dentine bonding agents to decrease the permeability of dentine tubules. This is usually a temporary solution.




If your still having sensitivity after the conservative options mentioned above (desensitise toothpaste and dentine bond) then your oral health practitioner may suggest dental fillings/restorations. Fillings/Restorations can help reduce the sensitivity by block the tubules and providing relief for a few years. The disadvantage of these fillings is they do wear down as they do not last forever, and you are committed to the restoration cycle.