Barrier membrane

A barrier membrane is a device used in oral surgery and periodontal surgery to prevent epithelium, which regenerates relatively quickly, from growing into an area in which another, more slowly growing tissue type, such as bone, is desired. Such a method of preventing epithelial migration into a specific area is known as guided tissue regeneration (GTR).

The first membranes developed were nonresorbable and required a second surgery for membrane removal some weeks later. The need for a second surgical procedure hindered the utilization of the original barrier membranes, which led to the development of resorbable membranes; research indicates no statistically significant difference in surgical success between the two types.

The purpose of a membrane is to prohibit the penetration of cells, primarily epithelial, through its structure.

When barrier membranes are utilized, the superficial soft tissue flap remains separated from the underlying bone for the primary healing period and must survive on the vascular supply of the flap; it cannot rely on granulation tissue derived from the underlying bone.

Two types of bony defects exist that may require the use of a membrane:

Space-making defects, such as extraction sockets with intact bony walls, are not as demanding as non-space-making defects, such as sites of ridge augmentation, where there may be no support for the membrane and the soft tissue cover may cause collapse of the membrane during healing.

Barrier membranes have been derived from a variety of sources, both natural and synthetic, and are marketed under various trade names. Membranes used in guided bone regeneration (GBR) and grafting may be of two principal varieties:

Historically, GBR and grafting techniques began with impractical millipore (paper) filter barriers. Expanded polytetrafluoroethylene (ePTFE) membranes were first used by 1984, being non-resorbable, but compatible with humans and not leading to infection. Although ePTFE is considered the standard for membranes and excellent outcomes have been achieved with this material, they are often contaminated with bacteria (which limits the amount of bone regrowth that will occur) and must eventually be removed via at least one extra surgery 4–6 weeks after the tissue has regrown. Resorbable membranes were developed to avoid these limitations. Non-absorbable ePTFE membranes are still used clinically on a regular basis, and long-term studies suggest that bones regrown with ePTFE function as well as non-augmented naive bone.

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