Tooth Sensitivity Explained


  Posted by: Dental Design      23rd February 2020

Most people have winced after a short, sharp twinge from a sensitive tooth. It often comes unexpectedly and pain originating in the oral cavity is perceived as disproportionately large compared to the rest of the body.2 Tooth sensitivity is a common, bothersome dental problem, which may restrict what an individual chooses to consume and impact on their quality of life.

Healthy teeth are protected by hard enamel on the crowns and cementum at the roots. However, if these layers are worn away or damaged, the more sensitive dentine is exposed. The dentine contains thousands of fluid-filled dentinal tubules that lead to the pulp, which contains the tooth’s nerve and blood supply. When stimuli such as liquids, foods or cold air make contact with the exposed tubules it alters the flow of fluid inside, which activates the nerves and triggers pain.[1]

Dentine exposure

Dentine can become exposed due to any combination of the tooth wear processes, including attrition, erosion and abrasion:[2]

Attrition – This is the loss of hard tooth substances due to tooth-on-tooth contact. Tooth grinding or bruxism are parafunctional habits that may be caused by stress, a misaligned bite or in some cases, diseases that affect the muscles. This activity thins the enamel and over time, wears it down until the dentine is exposed.

Erosion – Is the loss of hard tissue from the surfaces of the teeth due to chemicals such as acids. Dental erosion due to intrinsic factors is caused by gastric acid reaching the oral cavity during vomiting episodes or persistent gastro-oesophageal reflux. [3] Extrinsic factors include the frequent consumption of foods and beverages that are high in dietary acids. [4] Behaviours such as snacking or sipping acidic or sugary drinks expose the teeth to repeated acid challenges, which can cause the loss of surface tooth structure.[5]

Abrasion – This is the physical wear of the tooth surfaces due to mechanical processes other than usual actions such as chewing or tooth to tooth contact.[6] This type of tooth wear is associated with over vigorous or incorrect tooth brushing techniques as well as abrasive oral health products. It is often observed in individuals that use the teeth as tools to remove bottle tops or to hold nails etc. or those that use jewellery within the mouth on a long-term basis.

It should be noted that tooth whitening products have been identified is a risk factor for tooth sensitivity, as chemicals such as carbamide peroxide or hydrogen peroxide are able to quickly defuse through enamel and dentine and activate the nerve fibres.[7] Sensitivity from bleaching is usually transient, however if bleaching is performed on a patient that already has sensitive dentine, the sensitivity can be severe and prolonged.2 

Recession of the gums and loss of cementum

As well as loss of tooth enamel, the other main factors that can lead to tooth sensitivity are gum recession and loss of cementum. Gingival recession is common, affecting 60-90 per cent of the western European population, although reviews suggest that it is not age related.2 Nevertheless, recession of the gingival marginal tissues exposes the thin shield of cementum that protects the roots of the teeth. Cementum is less mineralised and softer than other mineralised tissues,[8] which means that once it is exposed to mechanical friction for instance, it can be lost rapidly to reveal the deeper dentine beneath.

Gum recession can be caused by a number of factors including periodontitis and the management of the condition, orthodontic therapy, prosthetic treatment that traumatises the gingival tissues, over-zealous tooth brushing and horizontal bone loss due to osteoporosis. Smoking is a risk factor strongly associated with periodontitis and also increases the likelihood of recession in periodontal tissues. Furthermore, gingival recession has also been observed in young adults with oral piercings as these may cause gingival tissue trauma.

Preventing sensitivity

Preventing the loss of enamel and/or cementum is the key to averting tooth sensitivity. Dental professionals can offer dietary advice and oral health instruction to help patients to protect their teeth. Fluoride treatments and sealants may also be helpful to remineralise the tooth surfaces. However, the CALCIVIS® imaging system provides dental professionals and their patients with an effective early warning system. This technology visualises active demineralisation on the surfaces of the teeth in real time, at the chair side. Using bioluminescence, the CALCIVIS imaging system detects the loss of minerals from the hard tissues of the teeth at the earliest, most reversible stages. Furthermore, the engaging CALCIVIS images help patients to understand their oral health status and comply with measures to remineralise the teeth before the sensitive dentine is exposed.

Exposed dentine is at particular risk for demineralisation and vulnerable to acid sources. As acids are produced by the bacteria in dental plaque on the tooth surface they can readily diffuse through the dentine and into underlying tissue resulting in tooth decay or infection. However, with the use of innovative technology, dental professionals can help patients to keep their teeth both healthy and pain free.


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[1] Preventing and treating tooth sensitivity. JADA Sept 2013:144 (9) 1084. [Accessed 5th August 2019]

[2] West N.X. et al. Dental hypersensitivity: pain mechanisms and aestology of exposed cervical dentin. Clin Oral Investig. 2013 Mar; 17(Suppl 1): 9–19. [Accessed 5th August 2019]

[3] Lussi A. et al. Erosion – diagnosis and risk factors. Clin Oral Investig. 2008 Mar; 12(Suppl 1): 5–13. [Accessed 5th August 2019]

[4] Zero D.T. Etiology of dental erosion – extrinsic factors. Eur J Oral Sci. 1996 Apr;104(2.Pt 2):162-77. [Accessed 5th August 2019]

[5] Scheutzel P. Etiology of dental erosion – intrinsic factors. Eur J Oral Sci. 1996 Apr;104(2.Pt 2):178-90. [Accessed 5th August 2019]

[6] Dental Health Foundation, Ireland. Tooth Wear. [Accessed 5th August 2019]

[7] Markowitz K. A new treatment alternative for sensitive teeth: A desensitizing oral rinse. Journal of Dentistry 41 Supp.1 S1-S11. [Accessed 5th August 2019]

[8]  Chen H et al. in Advanced Ceramics for Dentistry, 2014. 2.2.3 Cementum [Accessed 5th August 2019]

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