Prognosis of Crestally Placed Short Plateau Implants in Posterior Maxilla.

Crestal placement of short plateau implants in compromised jaws may cause implant failure due to bone overstress. The aim was to evaluate the impact of different sized implants on adjacent bone overload and the implant load-bearing ability in terms of the proposed index-ultimate functional load (UFL). Three-dimensional models of osseointegrated implants placed in types III and IV bone were analysed by the FEM for the case of patient-specific variations in cortical bone elasticity modulus. Maximum von Mises stresses in surrounding bone were calculated and compared with the cortical and cancellous bone ultimate strength characteristics to determine the UFL index for the studied implants. The implant UFL magnitudes were influenced by their dimensions, bone elasticity, and quality. The implant load-bearing ability was predetermined by cancellous bone strength. The maxilla with moderate elasticity modulus allows for the placement of wide short screwless implants in the compromised maxilla molar site with good clinical perspective.