I had a root canal done about 2 years ago. Lately I have noticed the tooth (which is towards the front of my mouth) getting darker. I went to a dentist that was recommended by my orthodontist. The dentist took xrays and said that he would be unable to fill it with bleach because he was afraid the tooth would crack because it is so hallow. So he said the only option is to put a crown over it, which I am fine with. He said I would have to have 3 separate appointments. He will have to put a piece of metal in the tooth to act as the stability for the tooth and then put the crown over it. For this one tooth it is going to cost me 4 times as much as what some other people I have talked to has paid for a crown. I suppose the reasoning for the high cost is because of this piece being placed. My only concern is if it is necessary to have this piece placed there. I have heard of many people having root canals and then needing to have a crown but I have never heard of there being a piece of metal in there that is specially made for the tooth. My mother in law has had a root canal done and then had a crown put on and it cost her $1800 less than what I am going to be charged. I am just curious as to if this is necessary or if this is just a way to make more money and it really isn't all that necessary.