Sensitive Teeth

What is dentin hypersensitivity?
More commonly referred to as sensitive teeth, dentin hypersensitivity can be defined by sharp pains of short duration (1-5 seconds) that come from exposed dentin (the inner layer that contains the nerve of the tooth found beneath the hard outer enamel layer).  Individuals that experience sensitive teeth may find that pain can be triggered by hot, cold, sour and sweet beverages or foods, forceful brushing and flossing and even by cold air.
What causes the sensitivity? 
The inner dentin layer is composed of thousands of tiny hollow tubes that are filled with fluid.  Tooth sensitivity is caused by the movement of the fluid within the dentin tubes which results in nerve irritation.  When the hard outer layer of enamel is worn down or if the gums have receded, the surfaces of these tiny tubes can become exposed, resulting sharp pain of short duration (1-5 seconds).
How can I avoid dentin hypersensitivity? 
Dentin hypersensitivity is one of the most common complaints among dental patients.  Avoiding frequent consumption of acidic beverages such as fruit juices (particularly citrus) and soda (remember, diet soda is still very acidic even though it contains no sugar) and also limiting your consumption of acidic foods you will decrease your risk of developing dentin hypersensitivity.  Conditions such as bulimia and acid reflux can have a similar erosive effect on tooth enamel.  Additionally, abrasion of the tooth's enamel can result from aggressive use of your toothbrush resulting in dentin hypersensitivity.
I have dentin hypersensitivity, what can I do to prevent pain?
Using a soft bristled toothbrush and brushing in a circular motion will minimize enamel abrasion and thus reduce sensitivity.  Using a desensitizing toothpaste will protect exposed dentin by blocking the dentin tubes. Avoid whitening toothpastes as these tend to be more abrasive and result in further loss of enamel.  As previously mentioned, limit your intake of acidic foods and beverages.  If you are experiencing sensitive teeth tell your dentist or hygienist, they can help you know the best way to manage the problem.