Tissue regeneration or grafting is promoted utilizing a structure including a multi-layer sheet of collagen membrane material which includes a purified collagen barrier sheet material derived from natural collagen-containing tissue, the barrier sheet material including a barrier layer with an outer smooth barrier face and a fibrous face opposite the smooth barrier face. The structure further includes a matrix layer of collagen sponge material adjacent to the fibrous face. The matrix layer of collagen sponge material is resorbed by a body of a subject at a substantially faster rate than the barrier sheet material.
