LAUSR

BACKGROUND This study evaluated the mechanical behavior of the All-on-4 concept performed with short-length distal implants with platform-switching (PSW) connection by using finite element analysis (FEA). METHODS Three models of the All-on-4 configuration were generated in human atrophic mandibles. The models consisted of tilted standard (AO4T; θ = 30°; 11 mm-length), straight standard (AO4S; θ = 0°; 11 mm-length) and straight short (AO4Sh; θ = 0°; 8 mm-length) distal implants. A resultant force of 300 N was performed obliquely in the left side and posterior region of the prosthetic bar. The von Mises equivalent stress (svm) and maximum and minimum principal stresses (smax and smin) were performed at the level of the prosthetic components/implants and peri-implant bone crest, respectively. RESULTS The AO4S configuration showed the lowest values of svm in the ML and DL abutments (37.53 MPa and 232.77 MPa, respectively) and dental implants (91.53 MPa and 231.21 MPa, respectively). The highest values of smax and smin were noticed in the peri-implant bone crest of the AO4T design. CONCLUSION All models presented lower odds of technical failures. The highest odds of peri-implant bone overload may occur when the All-on-4 concept is performed with standard-length 30o-angled distal implants with PSW connection.