Nonresorbable membrane for use as a space-maintaining barrier in guided tissue and bone-regeneration procedures. Composed of a thin, proprietary, microporous polytetrafluoroethylene (PTFE) film. Surface construction and the materials porosity make it suitable for adhesion of host cells to the material while preventing passage and integration of bacteria within the interstices of the material. Supple membrane conforms easily to tissue contours, yet offers sufficient stiffness to maintain space over the bony defect. Both smooth and microtextured surfaces are designed to prevent the tissue and bacteria ingrowth. Design allows for increased flap attachment for additional localized stability. Sterile.