What are the pros and cons of PEEK implants (paranasal) vs silicone vs Medpor?

All three materials you mentioned are permanent, non-resorbable implants. PEEK implants are extremely rigid. They have to be computer generated to fit the area precisely and are the most expensive. Medpor are the next most rigid. They are my least favorite because the porosity allows some degree of tissue ingrowth making them the most difficult to remove if they need to be replaced. Silastic implants are the least expensive, least rigid, easiest to remove or replace and therefore are my favorite. There are situations when a custom implant like PEEK may be desirable.