The invention relates to: - A resorbable crosslinked form stable membrane which comprises a composite layer of collagen material and inorganic ceramic particles containing 1.5 to 3.5 weight parts of inorganic ceramic for 1 weight part of collagen material, sandwiched between two layers of elastic pretensed collagen material, the collagen material comprising 50-100 % (w/w) collagen and 0-50 % (w/w) elastin, - the above crosslinked resorbable crosslinked form stable membrane for use as an implant to support bone formation, bone regeneration, bone repair and/or bone replacement at a non-containing dental bony defect site in a human or animal, - a process for preparing the above crosslinked resorbable crosslinked form stable membrane comprising the steps of: (a) Preparing a composite layer of inorganic ceramic particles and collagen material, optionally crosslinking that composite layer, (b) Assembling and glueing the composite layer of collagen material and inorganic ceramic particles between two layers of collagen material submitted to tensioning leading to a stretching of the collagen material in the linear region of the stress-strain curve, thereby giving a composite layer of collagen material and inorganic ceramic particles sandwiched between two layers of elastic pretensed collagen material, and (c) Crosslinking that composite layer of collagen material and inorganic ceramic particles sandwiched between two layers of elastic pretensed collagen material, followed by a hydrophilic making treatment.
