Finite Element Analysis (FEA) of Palatal Coverage on Implant Retained Maxillary Overdentures

Purpose: The aim of this study was to determine stress levels on supporting structures of implant-retained overdentures as a function of varying degrees of palatal coverage using finite element analysis modeling at different loading angles. Materials and Methods: ABAQUS®-software was used to perform finite element analysis on eight overdenture models with three and four implants and with and without palatal coverage designs. Loads were applied perpendicular and 45º to the implants. Von Mises stress was measured to determine bone stress. A one-way ANOVA determined which model caused the most stress to the maxillary bone. Results: Palatal coverage increased stress to anterior implant in three implant (p = 0.08) models but decreased stress to all implants in four implant models (p = 0.43). Distal implants received more stress than anterior implants for all models. There was no significant difference between a full palate and no palate coverage overdenture prosthesis when a bar was added under axial loading (p = 0.954). Under non-axial loading, a decrease in stress was noted with the bar in all areas except the anterior implant site. Conclusions: Palatal coverage may not be necessary when applying a pure axial load. The addition of a bar decreased stress at loading.