Sensitivity of teeth, DS (dentine sensitivity) or more recently DH (dentine hypersensitivity), is one of the most common clinical conditions encountered in dental practice worldwide.
It can have a significant negative impact on the quality of life of affected persons if not managed and treated properly.
Dentine hypersensitivity (DH) is characterised by short sharp pain from exposed dentine. It occurs in response to stimulation from cold, heat, touch, acids and osmotic changes and cannot be explained by any other dental defect or disease.
The necks of teeth near the gum margins are the most commonly affected areas, especially in the front incisor and premolar teeth regions.
Dentin hypersensitivity is caused by a variety of factors coming together which cause dentine, a living, highly enervated tissue, to become exposed to outside stimuli. These stimuli would normally only be encountered by the hard enamel, which protects the tooth and is not a living, sensitive tissue.
Toothbrush abrasion and gingival recession, brought about by excessive pressure from tooth brushing or from gum disease, has been identified as an important initiating factor. Dentine hypersensitivity eventually occurs due to loss of protective enamel and the opening of dentine tubules. This can be caused by exposure to a variety of acids contained in fruit drinks or due to gastric reflux.
The bouts of short sharp pain are thought to be caused by the movement of fluid within exposed dentinal tubules, which activate nerve endings near the dental pulp.
Dentine hypersensitivity can only be prevented and managed successfully by first diagnosing and dealing with the causative factors and removing them systematically one at a time.
They may include:
• Faulty tooth brushing, including use of hard brushes
• Using excessive force
• Scrubbing at the necks of the teeth
• Exposure to erosive agents from the diet and also internally from the body
The correct method of tooth brushing, using a soft brush, avoiding abrasive toothpastes and brushing two hours after exposure to acidic drinks will all help to reduce the loss of enamel from vulnerable areas prone to dentine hypersensitivity.
A detailed dietary history will help to identify the acidic foods and other acids which accelerate the loss of dental enamel and expose sensitive dentin. These acidic substances include soft drinks, citrus fruits, wines, yogurts and smoothies. Gastric reflux and eating disorders result in internal acids causing rapid enamel loss and dental erosion. Control or alteration of these co-factors will prevent recurrence of dentine hypersensitivity, especially when combined with the use of desensitising agents.
At home, desensitising agents are mostly in the form of toothpastes, mouthwashes and chewing gums. Only toothpastes containing combinations of potassium salts, fluoride ions, strontium, tin(II) [stannous], arginine and calcium carbonate, show evidence of limited efficacy and are best applied using a soft toothbrush without water and not rinsing afterwards. If there is no relief after 4 weeks, in-surgery desensitising should be requested.
In-surgery desensitising therapy is wide ranging and can encompass both short-term immediate relief and therapy aimed at more permanent relief. Various applications of topical fluoride are useful for temporary relief, while composite filling material and bonding agents, especially those containing a combination of gluteraldehyde, fluoride, benzalkonium and methacrylate, are showing promise for long term relief. New innovations in dentine hypersensitivity relief include bioglass, which is also used to repair bone and calcium silicate cement.
A major study is currently underway to investigate the efficacy of laser treatment.
1. Diagnosis and treatment of dentinal hypersensitivity: Porto C.M et al, Jour. Oral Science, Vol 51, No.3, 323-332, 2009
2. Potassium containing toothpastes for dentine hypersensitivity: The Cochrane Library, http;//onlinelibrary.wiley.com
3. Laser therapy for dentinal hypersensitivity: The Cochrane Library, http;//onlinelibrary.wiley.com