Is it true that I am not a candidate for dental implants? I feel like a lost cause.

I am 31 yrs old and I was diagnose with a hereditary form of advance peritonitis or something like that. I had to get my two lower front teeth extracted. My periodontist also did a bone graphing at the site of extractions for me. I asked him how long am I to wait before I can get my teeth implant. He told me I am only qualified for dental bridges because there is not enough bone. Am I really a lost cause, because I don't want to sacrifice 4 extra good teeth for a dental bridge if I can avoid it.