I am confused. One doctor says he could place implants right away, other says to do a bone graft first?

I had two evaluations from two respected periodontists. They looked at my X-rays and CT scan. I have fixed small brigdge that I need to replace with two implants. One doctor told me that I needed bone graf and he could placed the implants right away. The other one told me to do bone graf first, wait four months and then he could place the implants after that period. Any suggestions?