Influence of cantilever length on stress distribution in fixation screws of All-on-4 full-arch bridge

Abstract

The All-on-4 concept is a useful therapy in the treatment of an edentulous mandible. Just few studies have shown the effect of the cantilever length on fixation ele-ments. The aim of the study was to clarify the influence of the cantilever length and implant position relating with load position on the stress and their distribution in fixation screws in the framework of the All-on-4 concept. There were analyzed how and in what degree the mentioned factors influence dynamics of change of stress in fixation screws. The results show that implantologists would not turn implants close each other and do not use cantilevers as long as three teeth. The most advantageous implant positioning is 4-2-2-4. The worst case is when implants locate near each other (case 3-2-2-3). Two nearby implants act as one. Therefore screws receive greater loads.