Implant Treatment Plan for Patient Who Lost Teeth to Periodontal Disease?

Dr. B. asks:
I have a middle age female patient who recently lost all her maxillary teeth to periodontal disease. She came to the United States from the third world where her nutrition and oral health care were very poor. She has a small frame, small face and thin residual maxillary alveolar ridges. She has several fixed partial dentures on her mandibular arch. My treatment plan is for a maxillary full arch fixed partial denture. I am just wondering if it might be better to do this in 3-segments – 1 anterior and 2 posterior. I am concerned that if one or more implant fails, I may have to redo the full arch one-piece maxillary fixed partial denture. Most of the implant supported fixed partial dentures that I do are single unit or 3-5 units. I would appreciate some advice from more experienced practitioners before proceeding. Any thoughts?