An intra-vertebral body height restoring device includes a body for insertion into an intra-vertebral space. The body includes top and bottom surfaces for engaging opposing vertebral surfaces defining the intra-vertebral space. The body includes at least two layers extending along a width of the body and having a fully expanded and fully collapsed height relative thereto. A reversible expansion mechanism selectively and reversely expands and collapse the height of the layers and including the fully expanded and collapsed heights to restore a selected height to the intra-vertebral space.