Bone grafting

Hi, I have undergone root canal treatment years ago. A few days back when I was eating a chicken leg my crowing got damaged. I managed with the uncrowned tooth for a day. Next day onwards I started to suffer from a toothache. I went to a dentist in my place. He told that recrowning will not help because the complete tooth has damaged. So I asked what can be done to solve this problem. He suggested and took an appointment for bone graft for the dental implant from a clinic in Lexington ( http://concordlexington.com/procedures/bone-grafting/ ). Is this bone graft a necessary thing. The complete extraction followed by bone graft and the dental implant will take a long time? From where will they take bone for grafting? After bone grafting followed by tooth implantation is there any chance for tooth decay?
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