Traditional dentures (either complete or partial) are typically removable, but there are two types of permanent or semi-permanent dentures: overdentures and permanent dentures.    Overdentures are implant-retained, snap-in that can be taken out. Overdentures usually require between two and six implants to be placed in the jaw and covered with abutments, to which the dentures are connected. Overdentures must be removed so you can clean the dentures, the abutments, and your gums.    Permanent, or fixed, dentures are implant-supported and can only be removed by a dentist. Permanent dentures typically require 6-8 implants in the upper arch and 4-6 in the lower jaw. Permanent dentures do not need to be removed to be cleaned; you can brush and floss them just like your natural teeth. Neither overdentures nor permanent dentures will rub, slip, or pop out unexpectedly.