Approximately from 1 year my mouth is smelling and I found some different type of taste after sleeping but from 3 months there is problem in my one teeth, that when I am taking cold water or cold thing then I feel coldness sock in a teeth and when I chew something with that teeth then I found different types of pain in that and now 5 days ago I found a hole in that teeth. So please suggest me that what treatment I have to take.