Membrane for tissue or bone regeneration

摘要

A structure comprises a membrane for tissue or bone regeneration. The membrane contains at least three layers; the two outer layers are made of a natural material and the inner layer(s) are made from one or more plastic materials. The plastic material is preferably a biodegradable thermoplastic based on poly- alpha -hydroxy acids (e.g. polytrimethylene carbonate, polydioxanone, polyglycolide, polylactide or poly(L-lactide-coglycolide), or poly orthoesters and/or polycaprolactones (e.g. polyhydroxybutyrate or polyhydroxybutyrate-co-hydroxyvalerate). More specifically, the plastic is poly(D,L-lactide) or poly(L-lactide-co-D,L-lactide) where the ratio of L-lactide to D,L-lactide ranges from 40:60 to 80:20. The inner plastic layer has a cell-occlusive non-porous structure. The natural outer layers contain collagen (type I and/or type IV) and may have a porous, smooth or fibrous structure. The membrane has a collagen rim 5-10 mm thick, and is moulded into a three dimensional shape. The porosity and thickness of one of the outer layers is different from that of the other; the pores in the layer nearest to the bone defect are 1-5 mm<3>. This layer may also contain autological bone material.