Hi well sometimes implants are put in instead, I don't know how practical it is for a whole mouthful. When I find people who plan to get all their teeth out this would be an excellent reason not to have them out. Perhaps we should all encourage people to take care of the teeth they have so this does not have to happen to them.
Are lots of sweets taken? How is the rest of health?
A hefty food processor and a little tomato juice might help with a pizza. True it is not as fun but at least some things could be eaten that otherwise would not be. Pizzas can be made at home with one's own ingredients skipping cheese which is not healthy anyway. Fake nut cheeses can be made and may even taste better than the real cheese in my opinion. Vegetables could be lightly cooked and blended also. Hope this helps get some nutrients into a person.