Dentine hypersensitivity

Dentine hypersensitivity is sensation felt when the nerves inside the dentin of the teeth are exposed to the environment. The sensation can range from irritation all the way to intense, shooting pain. This sensitivity can be caused by several factors, including wear, decaying teeth or exposed tooth roots.

Dentine contains many thousands of microscopic tubular structures that radiate outwards from the pulp; these dentinal tubules are typically 0.5-2 micrometres in diameter. Changes in the flow of the plasma-like biological fluid present in the dentinal tubules can trigger mechanoreceptors present on nerves located at the pulpal aspect thereby eliciting a pain response. This hydrodynamic flow can be increased by cold, air pressure, drying, sugar, sour (dehydrating chemicals), or forces acting onto the tooth. Hot or cold food or drinks, and physical pressure are typical triggers in those individuals with teeth sensitivity.

Treatment can consist of amorphous calcium and phosphate, NovaMin, potassium nitrate, strontium chloride, gluma, fluoride therapy, or calcium sodium phosphosilicate.

Potassium nitrate is commonly used in toothpastes such as Sensodyne or Crest Sensitive as a remedy and is approved as a monographed drug by the FDA. Nonetheless, there remains some dispute about its effectiveness.^[1] Strontium chloride and strontium acetate are used in Sensodyne Original and Sensodyne Mint toothpastes. The mode of action is linked to their ability to form mineralised deposits within the tubule lumen and on the surface of the exposed dentine that help prevent transmission of the applied stimulus.

One cause of sensitive teeth can be traced to nocturnal gastroesophageal reflux disease (acid reflux). Stomach acid can reach the teeth and cause enamel loss and prevent re-mineralization.^[2]

Prevalence

A study conducted at Queen's University, Belfast, determined that the prevalence of reported sensitivity was 57.2%. In most cases the incidence occurred in the 30-39 year age group. Although the majority of individuals reported that cold was the major stimulus for pain, other causes such as toothbrushing, hot, and sweet stimuli were reported as well. This study found the prevalence of dentine sensitivity to be much higher than in previous reports. These results suggest an increase in the levels of sensitivity within the general population.^[3]

Prevention

Before the proper treatment for a patient is defined, it is important to first prevent, modify, eliminate or control etiologic factors such as plaque, improper toothbrushing, and a diet high in fermentable carbohydrates and/or acidic foods.^[4]

Some examples of acidic foods are fruits, fruit juices and wine whose acids can remove smear layers and open dentinal tubules. Toothbrushing with abrasive toothpaste may abrade the dentin surface which may open up dentinal tubules if combined with erosive agents. One recommendation for patients is to avoid toothbrushing for at least two to three hours after consuming the above mentioned acidic foods or drinks.^[5]

Treatments

There are different options to treat dentine hypersensitivity that can be divided in at-home treatments, those the patient can apply, and in-office treatments, those applied by the dentist.

At-home treatments

At-home treatments include desensitizing toothpastes or dentifrices, potassium salts, mouthwashes and chewing gums.

Desensitizing toothpastes containing potassium nitrate have been used since the 1980s while toothpastes with potassium chloride or potassium citrate have been available since at least 2000.^[6] It is believed that potassium ions diffuse along the dentinal tubules to inactivate intradental nerves. However, as of 2000^[update], this has not been confirmed in intact human teeth and the desensitizing mechanism of potassium-containing toothpastes remains uncertain.^[7] Since 2000, several trials have shown that potassium-containing toothpastes can be effective in reducing dentine hypersensitivity, although rinsing the mouth after brushing may reduce their efficacy.^[6]

Studies have found that mouthwashes containing potassium salts and fluorides can reduce dentine hypersensitivity, although rarely to any significant degree.^[6] As of 2006^[update], no controlled study of the effects of chewing gum containing potassium chloride has been made, although it has been reported as significantly reducing dentine hypersensitivity.^[6]

In-office treatments

In-office treatments might be much more complex and they may include the application of dental sealants, having fillings put over the exposed root that is causing the sensitivity, or a recommendation to wear a specially made night guard or retainer if the problems are a result of teeth grinding.^[8]

Other possible treatments include fluorides are also used because they decrease permeability of dentin in vitro. Also, potassium nitrate can be applied topically in an aqueous solution or an adhesive gel. Oxalate products are also used because they reduce dentin permeability and occlude tubules more consistently. However, while some studies have showed that oxalates reduced sensitivity, others reported that their effects did not differ significantly from those of a placebo. Nowadays, dentine hypersensitivity treatments use adhesives, which include varnishes, bonding agents and restorative materials because these materials offer improved desensitization.^[9]

Other procedures

Other procedures include ionto-phoresis, usually used in conjunction with fluoride pastes or solutions. Another procedure is the use of low level laser therapy. A study involving 1102 teeth of 388 patients determined that when used with the correct irradiation parameters, LLLT was effective in treating dentinal hypersensitivity. This therapy quickly reduces pain and maintains a prolonged pain-free status in 91.27% of the cases.^[10]

See also

• Tooth
• Dental pulp
• Toothpaste
• Remineralization of teeth
• Bioactive glass

References

1. ^ Poulsen S, Errboe M, Lescay Mevil Y, Glenny A-M (2001). Potassium containing toothpastes for dentine hypersensitivity. In Poulsen, Sven. "Cochrane Database of Systematic Reviews". Cochrane Database of Systematic Reviews 3 (2): CD001476. doi:10.1002/14651858.CD001476.pub2. PMID 16855970. http://www.cochrane.org/reviews/en/ab001476.html. 
2. ^ Reflux Disease May Cause Sinusitis and Damage Teeth
3. ^ Prevalence of dentine hypersensitivity in a general dental population. PMID 9584750. 
4. ^ "Managing dentinal hypersensitivity". http://www.dental-tribune.com/articles/content/id/1968/scope/specialities/section/dental_hygiene. Retrieved 2010-05-06. 
5. ^ "Prevention of Dentin Hypersensitivity". http://jada.ada.org/cgi/content/full/137/7/990#R6. Retrieved 2010-05-06. 
6. ^ ^{a b c d} "Managing dentin hypersensitivity". 2006. http://jada.ada.org/cgi/content/full/137/7/990. Retrieved 2010-11-06. , J Am Dent Assoc, Vol 137, No 7, 990-998
7. ^ The efficacy of potassium salts as agents for treating dentin hypersensitivity, Orchardson R, Gillam DG, Division of Neuroscience and Biomedical Systems, Institute of Biomedical and Life Sciences, University of Glasgow, J Orofac Pain. 2000 Winter;14(1):9-19
8. ^ "Crest Sensitivity Syndrome". http://sensitivitysyndrome.com/crest.php. Retrieved 2010-05-06. 
9. ^ "In-office treatments". http://jada.ada.org/cgi/content/full/137/7/990#R6. Retrieved 2010-05-06. 
10. ^ "Laser Therapy in the Treatment of Dental Hypersensitivity". http://www.walt.nu/docs/millenium-edition/03Brugnera.pdf. Retrieved 2010-05-06. 

External links

• Potassium nitrate toothpaste for dentine hypersensitivity
• Sensitive Teeth, Causes and Treatment