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Tooth ache ie: pain in the tooth, can be due to various reasons, most common being:
-Caries (bacteria) in the tooth causing cavity
-food lodgement in a cavity on a single tooth or in between two teeth
-Fracture of tooth
-Sensitivity in tooth due to erosion of enamel due to either acidity or else extremely hard tooth brushing

You must visit your dentist if you are suffering from tooth ache as he may take an Xray for the aching tooth and after clinically examining your teeth and oral cavity, he will do the needful.
If you feel that food gets stuck in the tooth or in between teeth or if the dentist finds caries or cavity in the aforementioned tooth then you need to get the cavity cleaned and then filled accordingly.

Sensitivity due to loss of enamel surface can be treated by either using desensitizing pastes or dentinal blocking agents placed on the area by your dentist.

If you have any more queries i will be happy to help.
Regards

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