Comparison between all-on-four and all-on-six treatment concepts and framework material on stress distribution in atrophic maxilla: a prototyping guided 3D-FEA study - Bhering, C LB; Mesquita, M F; Kemmoku, D T; Noritomi, P Y; Consani, R LX; Barão, V AR (Mater Sci Eng C, 2016)