Being referred to an endodontist?? what should i expect?

Toady i went and seen the specialist who removed my wisdom teeth a few months ago who i had been referred to by my dentist. i have a rather small red dot on my front left tooth close to the gum -- my dentist thought it may have been from the aneathisist when i was put to sleep while my wisdom teeth were coming out. the specialist today ured me that wasnt the cause and that it looked looks like a rare condition where my gum has started to eat away at my tooth?? i cant remember the name of it??? anyway its made a small hole and he has referred me now to an endodontist -- he has marked it as urgent im very nervous. in the mean time he wants me to stay away from really cold things like drinks and sweet things as it can make it worse and possible make the hole deeping he isnt sure how deep it is. i think that is what the endodontist will find out. if it gets deeper it will go to my nerve and possible kill and then he said something about dental implant he gave me a brochure about it. i may ahve to have a filling on my front tooth wil i need a crown too??