A method of making a preformed dental membrane , comprising the steps of: Obtaining (S100,S102) a virtual 3D image of an area of bone to be augmented, said virtual 3D image of said area of bone to be augmented including a virtual representation of a surgical site (4;7); digitally packing (S104) said virtual representation of the surgical site (4;7) with virtual bone graft substitute ; designing (S106) a virtual preformed dental membrane to be placed over the virtual bone graft substitute based on the virtual bone graft substitute and the obtained virtual 3D image of the area of bone to be augmented; and fabricating (S110) said preformed dental membrane from the virtual preformed dental membrane characterized in that (i) the step of fabricating (S110) includes printing the preformed dental membrane directly into its shape that matches the shape of a customized bone graft material, wherein the manufactured preformed dental membrane is made of collagen, non-resorbable polymers, resorbable polymers, synthetic resorbables, and/or natural resorbables; or (ii) the step of fabricating (S100) includes printing the preformed dental membrane directly on top of a customized bone graft material to form a component comprising the preformed dental membrane and the customized bone graft material; or (iii) the method further comprising a step of flattening (S108) the virtual preformed dental membrane into a substantially flat virtual digital representation of the preformed dental membrane , and once the virtual preformed dental membrane is flattened, it is manufactured by 3D printing. Obtaining (S100,S102) a virtual 3D image of an area of bone to be augmented, said virtual 3D image of said area of bone to be augmented including a virtual representation of a surgical site (4;7); digitally packing (S104) said virtual representation of the surgical site (4;7) with virtual bone graft substitute ; designing (S106) a virtual preformed dental membrane to be placed over the virtual bone graft substitute based on the virtual bone graft substitute and the obtained virtual 3D image of the area of bone to be augmented; and fabricating (S110) said preformed dental membrane from the virtual preformed dental membrane characterized in that (i) the step of fabricating (S110) includes printing the preformed dental membrane directly into its shape that matches the shape of a customized bone graft material, wherein the manufactured preformed dental membrane is made of collagen, non-resorbable polymers, resorbable polymers, synthetic resorbables, and/or natural resorbables; or (ii) the step of fabricating (S100) includes printing the preformed dental membrane directly on top of a customized bone graft material to form a component comprising the preformed dental membrane and the customized bone graft material; or (iii) the method further comprising a step of flattening (S108) the virtual preformed dental membrane into a substantially flat virtual digital representation of the preformed dental membrane , and once the virtual preformed dental membrane is flattened, it is manufactured by 3D printing. (i) the step of fabricating (S110) includes printing the preformed dental membrane directly into its shape that matches the shape of a customized bone graft material, wherein the manufactured preformed dental membrane is made of collagen, non-resorbable polymers, resorbable polymers, synthetic resorbables, and/or natural resorbables; or (ii) the step of fabricating (S100) includes printing the preformed dental membrane directly on top of a customized bone graft material to form a component comprising the preformed dental membrane and the customized bone graft material; or (iii) the method further comprising a step of flattening (S108) the virtual preformed dental membrane into a substantially flat virtual digital representation of the preformed dental membrane , and once the virtual preformed dental membrane is flattened, it is manufactured by 3D printing. <EOS>