ritabrenke - get your oncology doctors to write a letter to your medical insurance company about your need for the obturator. This is definitely a medical need, though it is often made buy a dental prosthodontist. That prosthodontist that you talked to knows this. Dental professionals do not like to deal with medical insurance companies, and fill out all the forms, but at the end of the day this should be commonplace for a maxillofacial prosthodontist. If you saw a regular prosthodontist, look for another one that specializes in maxillofacial work. You will have way less issues with him taking your medical insurance. Another issue is that you may (I am guessing) have moved to someplace outside your coverage area, which creates a hole 'nuther bag of worms.

Also re geting the "final one" , this takes time. Your mouth is healing and going through many physical changes in shape as this takes place - particularly in the first year. That all has to settle down before you get the final appliance. Even that one will have to be remade (or at least the tissue side of it relined) every few years to stay nice and tight and sealed when you are wearing it.