I Am Getting A Root Canal Tooth Extracted (a Molar;

I am getting a root canal tooth extracted (a molar; #30). It is not infected, but has since fractured after the crown became loose. I will not be getting an implant, but will instead be getting a bridge. How necessary is it for me to get a bone graft (allograft)? The reason I ask is that I have an immune system disease and my PCP is concerned I might not react well to the foreign material. But my dentist is worried about loss of bone in the area. So, I don't know what to do. How necessary is a graft if not getting an implant?