Introduction

Trying different cuisines adds pleasure to our life but it gets difficult when we start feeling pain and discomfort while having them. Tooth discomfort can be caused by various factors such as; you might have a tooth cavity, a cracked tooth or side effects of some dental procedure like bleaching. But when the cause is result of worn tooth enamel or exposed tooth roots then you typically have sensitive teeth. Hyper-sensitivity is defined as the sharp pain of short duration, arising from exposed dentin surfaces in response to stimuli because of the following reasons; thermal (temperature) which is due to drinking of hot and cold liquid, eating ice cream etc; tactile (touch) which is while brushing, touching with finger; chemical while eating sweets and electrical in case you have metallic filling in your mouth.

Understanding sensitivity

Our tooth has typically three layers i.e. outermost layer, middle layer and innermost layer. The outermost layer is called enamel which is hardest substance in our body thus not sensitive to any changes and protects our teeth. The middle layer is called dentin which is covered with enamel on crown part and by cementum on root part. The layer of root that is covered by cementum is prone to wear and tear. This layer is very much sensitive to any thermal, chemical or mechanical change and when this layer becomes exposed you start feeling sensitivity and discomfort. Dentin contains little tubules that are linked to nerves inside the tooth and when dentin is exposed the nerves get stimulated and thus results in pain. Innermost layer is pulp that is soft tissue part of tooth which has nerves and blood vessels.

Theories of dentin sensitivity

There are few theories that have explained the sensitivity as follows

• Brunnstrom's hyper-dynamic theory: Brunnstrom's hyper-dynamic theory states that any stimuli (such as cold or hot, sweets or breathing in cold air) are transmitted to pulp surface through movement of fluid present in dentinal tubules. This deforms the nerve group of A-fibre in pulp or pre-dentin and damages the odontoblast cell thus causes pain.
• Neural theory: The neural theory states that there is activation of nerves ending lying within the dentinal tubules and the nerve signal are conducted along the nerve fibres in pulp, into the nerves and then to brain.
• Odontoblastic transduction theory: It states that stimuli excites the body of odontoblast and the odontoblast are closely attached to nerve ending of pulp or dentinal tubule and thus it transmit the excitation of these associated nerve endings.

What are the causes of sensitivity

After understanding that what is sensitivity now let’s understand the causes of it.

• Faulty tooth brushing

  We need to brush our teeth daily to keep them healthy and hygiene. But brushing too vigorously can cause wearing away of enamel and recession of gums. Moreover sometimes we brush immediately after a meal which is not the correct way. One should brush only after 30 minutes of having a meal as just after meal the enamel on the tooth surface is soft and easily worn away by brushing.

• Acidic beverages

  Aerated soft drink contains acidic content and has low ph level that can cause enamel erosion and leads to exposure of dentin ultimately sensitive teeth.

• Gum diseases also known as gingivitis

  Brushing too vigorously can cause receding gums that leads to exposure of cementum which is less resistant to wear and tear. This leads to inflamed or sore gums which causes the worn away of the supporting ligaments and thus leads to exposure of the underlying surface and nerves of tooth.

• Teeth grinding

  Sometime knowing or unknowingly we clench our teeth either during last over of interesting cricket match or last minutes of football match or when we are very angry. If this is for very short span of time, it might not cause much damage. Once it becomes a habit of grinding your teeth during sleep (bruxism) or during the day (bruxomania) it leads to damage of your teeth as well as temporomandibular joint. It leads to wearing down enamel and exposing underlying dentin.

• Toothbrush abrasion

  As brushing our teeth daily is required for good oral health similarly improper use of toothbrush coupled with force, method, frequency and duration of tooth brushing can lead to pathologic tooth wear and leads to sensitive teeth. If we brush haphazardly or for longer time or too many times a day, it can cause damage to our teeth. Moreover the toothbrush should be ideally changed as soon as the bristles are frayed and in no case the brush should be used greater than 3 months, as the frailed away bristles causes recession of gums and hence sensitivity of teeth.

• Tooth erosion

  Tooth erosion is progressive loss of hard substance of tooth by chemical processes that do not involve any bacterial action. Example is a patient with GERD (Gastro- esophageal Reflux Disease) and eating disorders like Anorexia, Nervosa bulimia self induced vomiting after having a meal (particularly in young female ). It leads to exposure of tooth substance to acidic gastric content leading to tooth erosion and sensitivity.

• Cracked teeth

  Chipped off or broken teeth may fill with bacteria from plaque. Bacteria can enter the pulp, causing inflammation and can have pain and sensitivity in that tooth.

Self-check if you too have sensitive teeth

1. If the intake of anything cold such as eating ice cream or drinking cold drinks causes you pain. Cold drinks that have sugar could cause your tooth to ache more than cold drink such as water or tea without sugar.
2. If the intake of any hot drinks causes you pain or discomfort.
3. If pain occurs on touching tooth with your tongue, by the finger or during brushing then it is a sign of sensitive teeth.

Prevention

1. Gingival recession and cervical tooth wear can be avoided by healthy dietary and oral hygiene practice.
2. Using a non-traumatic tooth brushing techniques (modified bass technique) will help in prevention of receding gums and tooth wear around cervical margin of teeth. If you have any doubt you can take the opinion of your dentist.
3. One should prefer tooth pastes rather than tooth powder as it has low abrasive quality.
4. Brushing should be done twice a day.
5. Lukewarm water rinses are also beneficial in prevention.
6. One should avoid taking acidic food and drinks or should reduce its intake.
7. Flossing can also be done so as to avoid recession of gum.

Home treatment

1. For initial stage use of medicated tooth paste containing – nerve desensitizer potassium nitrate, sodium fluoride, stannous fluoride and calcium phosphate can give you some temporary relief.
2. Mouth washes containing desensitizing agents can be used.

Dental office treatment

1. Application of dental sealant, having filling put over the exposed roots that is causing sensitivity.
2. Application of fluorides on teeth is also helpful.
3. Professionally applied Dentin adhesive sealers-fluoride varnishes, glass ionomer cement, composites, dentin bonding agents can give you relief from sensitivity.
4. Lasers- Nd:YAG and Er:YAG laser treatment is also available. Night guard or retainers are given in cases of teeth grinding.

References

1. Carranza 10th Edition.
2. Canadian Advisory Board On Dentin Hypersensitivity .Consensus-Based Recommendation For The Diagnosis And Management Of Dentin Hypersensitivity.
3. Current Concept Of Periodontics By B.R.R Varma And R.P.Nayak.
4. Grossman’s Endodontic Practice-Twelfth Edition. By B.Suresh Chandra And V.Gopi.Krishna.
5. American Dental Association Sensitive Teeth 09 September 2007.
6. Journal Of Contemporary Dental Practice Volume 6 no.2 May 15,2005.