I was recently told by my new dentist that a previosly done root canal was done incorrecly (drilled too deep ) and would have to be either redone correctly or extracted the good news is there was no alalgam used to seal the root tip ,but the dentist told me that if it is extracted he would recommend using a bone graft to build up the area again , the bone grafts come from a cow ,has any one out heard about this and if so was it bad or good ? don't want to be chewing my cudd the rest of my life if I don't have to