A surgical blockade used in Guided Bone Regeneration (GBR). It is placed over a bone graft site to separate the slow-growing bone cells from the fast-growing gingival (gum) tissue.
Gingival tissue grows much faster than bone. Without a physical barrier, soft tissue would migrate into the bone defect, preventing the graft from solidifying into hard bone capable of supporting an implant.
It is a biological or synthetic "shield" that creates a secluded space, allowing bone progenitor cells to populate the graft site without competition from gum tissue.