Tooth sensitivity is caused when the enamel of teeth is worn down or gums have receded, stimulating cells within tubes located in the dentin. The dentin is protected by gums and enamel shell of the teeth. But when this protection is reduced due to improper brushing or teeth disease or chipping or cracking of tooth, the microscopic holes in dentin transmits heat to the tooth nerve. This creates sensitivity.
Hot and cold temperature foods cause your teeth to expand and contract. This can lead to the development of microscopic cracks in the teeth over the time passing these sensations to seep through to the nerves.
Some toothpastes contain abrasive ingredients that may be too harsh for people who have sensitive teeth. Ingredients found in some whitening toothpastes that lighten and/or remove certain stains from enamel, and sodium pyrophosphate, the key ingredient in tartar-control toothpastes may increase tooth sensitivity.
No body should eat very hot or very cold foods or drinks, and never one after the other. The author of this article once ate a baked corn on the cob, not realizing very high level of heat captured in it. The hotness immediately transferred to the gums and root of two teeth causing severe pain and damaging the tooth instantly. Two teeth later required root canal.