Lately, I get severe toothache every time I eat or drink. What could be the cause of such sensitivity in my teeth and how can I prevent it?

This is a common condition. Pain or sensitivity after eating or drinking can be due to many reasons. If the discomfort lasts for only 
a few minutes, it is most likely due to tooth decay, a fractured filling or exposure of the roots of your teeth due to recession of the gums.

A sharp pain in a particular tooth when eating is also indicative of decay or a fracture of the tooth.

If the pain persists even after you have finished eating or drinking, it suggests there is a more serious problem. The decay could have spread deep into the tooth and damaged the pulp.

It is important that you see a dentist for a correct diagnosis. Mild sensitivity due to recession can be treated using local desensitising agents and medicated toothpastes. But if the pain and sensitivity is due to decay or inflammation of the pulp, extensive treatment may be required, including tooth restoration or a root canal therapy.

In rare cases where the pain or sensitivity is due to a fracture of the tooth that cannot be restored, the tooth may have to be extracted.