The "best" treatment varies from patient to patient
Without seeing xrays, 3D images of bone, sinus anatomy, etc, it is impossible to say what is best for YOU. There ARE general rules, but they get "broken" all the time. 8-10 implants per arch is a common suggestion and predictable. The restoration that is secured to the implants is also important, choosing from an implant supported denture (acrylic), a full zirconia bridge (prettau?), or a BDT method that combines many products that allows repairability in the future.
Treatment like this requires finding a dentist that is familiar and experienced with all options so that they can make the best recomendation for you.
All on 4 by NOBEL BIOCARE
proven protocol, and you will have strong titanium bar, fixed solution within just couple of days, is the only proven protocol, that can give you immediate results ,
less implants but great layout, you will love your teeth.
You know are going fixed. You know you will have implants. "General" rule is an implant per two teeth. Replacing 10 teeth? You would need at 5 implants. Replacing 12 teeth - then 6 implants. You get the drift. Use this as a platform to discuss with your dentist. Everyone's bone, arch form, mouth size, history of missing teeth and more is different. You want to trust your dentist and talk it through until you are satisfied. You could also get to another dentist for a second opinion and choose your best solution. It is a very important, timely and costly decision you are making. You do want to have chosen the right person, someone you trust and can work with. Definitely keep going the extra mile in this investigation, preparatory and decision process. It will pay off for you in the long run.
If it were my mouth, I would like bridges. Most of my pictures are of porcelain or zirconium. In fact I have done only two of those all on 4 that are plastic & have screw holes since I don't charge a different fee for a different material. Each one has their advantages & disadvantages. Something to discuss with your doctor.