Does your morning coffee make you wince in pain, or your sundae make you want to scream?  You may be among the one in eight American adults with sensitive teeth. Sensitive teeth are caused when the tooth enamel erodes, exposing the bony tissue beneath it. Known as dentin, this bony tissue is full of microscopic, hollow tubes that connect to the nerve endings in your teeth. When exposed to hot or cold foods, those nerves can cause a sharp, painful reaction.