Full Arch Overdenture or Free-Standing Implants?

Dr. M asks:
I am doing my first full arch case. It is an edentulous maxilla with excellent bone volume and density opposing a mandibular removable partial denture.

My surgeon recommends that he place 6 dental implants and that I do a full arch bar overdenture. He says the bone will eventually fail around single free-standing dental implants in the maxilla. However, the attachment manufacturer says that all I need is 4 free-standing dental implants placed in the second premolar and canine areas. My lab says either design will work and they are doing both kinds of designs for their doctors. Money is not an object. What have you been doing in dental implant cases like this?