Abstract

This systematic review compares marginal bone loss (MBL) and mechanical complications associated with two-and three-implant-supported fixed dental prostheses (FDPs) in edentulous patients, with attention to prosthetic design, implant surface, cantilever use, and implant-abutment configuration. The review followed Systematic Reviews and Meta-Analyses guidelines. A search was conducted in PubMed, Scopus, and Web of Science for clinical studies published from 2000 to 2025. Inclusion criteria included randomized controlled trials, cohort studies, and clinical investigations with a minimum follow-up of 12 months that reported on MBL and prosthetic or biological complications in two- and three-implant-supported FDPs. Eleven eligible studies were included in the qualitative synthesis. In the included studies, both two- and three-implant FDPs showed comparable outcomes in terms of MBL and implant survival. Mean MBL ranged from 0.1 to 1.25 mm, with no significant differences between configurations. Implant surface characteristics were associated with reduced MBL compared to machined surfaces. Cantilevered FDPs exhibited higher MBL and more frequent mechanical complications, including screw loosening and veneer fractures. Studies involving standardized full-arch prostheses supported by three implants demonstrated high survival rates with minimal complications. MBL and mechanical complications were influenced more by prosthetic design, the presence of can tilevers, and implant surface type than by the number of supporting implants. Two-implant-supported FDPs performed equivalently to three-implant designs when biomechanical planning was optimized and cantilevers were avoided.

Key words: Marginal bone loss, implant-supported prosthesis, fixed dental prosthesis, cantilever, implant surface, prosthetic complications, implant number, two implants, three implants