In cemented (bonded) systems, the crown is bonded to the implant component using traditional cements. The clinical advantage is that the crown has no screw holes, resulting in excellent aesthetics, and the adhesive cement absorbs micro-heights. The biggest disadvantage is the risk of cement remnants seeping below the gum line not being completely cleaned, creating “peri-implantitis” (implant-loss inflammation) around the implant. In screw-based systems, the prosthesis is screwed directly to the implant; no adhesive is used. The biggest advantage is that the prosthesis can be removed from the mouth by the dentist at any time by removing the screw, repaired, and cleaned (reversibility). The disadvantage is the presence of small screw holes on the chewing surface of the teeth (these holes are sealed with composite), and laboratory precision is much higher.
