A medical barrier made by micro porous expanded polytetrafluoroethylene (ePTFE) is disclosed. The medical barrier allows the attachment and ingrowth of cells and tissue to within one, two or several cellular length, but not across the sheet material, and the tissue can still be pulled or peeled apart from the micro porous sheet with non-surgical and non-traumatic procedures. This medical barrier of the present invention is particularly useful in guided tissue regeneration in the repair of bone defects, as for example in the repair of alveolar bone defects. The medical barrier prevents the entry of rapidly migrating gingival tissue cells into the defect and allows the alveolar bone to regenerate.
