Barrier membrane

The concept of Guided tissue regeneration in periodontics, in that barrier membranes could be used to promote selective cell population of the root surface, which facilitates periodontal regeneration or the regeneration of the bone, cementum, and the periodontal ligament, while simultaneously excluding the epithelial and gingival cells. The creation of space under the membrane is the primary prerequisite to this regenerative technique.

Types

Nonabsorbable membranes

Nonabsorbable membranes are usually made of a porous, polytetrafluoroethylene (e-PTFE), or nonporous (high-density) PTFE. When properly used, these membranes will result in the regeneration of bone over alveolar ridges and bone, [[cementum], and periodontal ligament around teeth. These membranes have been used for both root coverage and ridge augmentation. The porous e-PTFE membranes should stay submerged throughout the healing phase, but the most common complication is exposure of the membrane, which will often lead to infection and failure of the technique. Success occurs when the soft tissue covering the membrane remains intact for a minimum of 30 days and ideally for 6 months or longer as needed for maturing of the newly formed bone. If the membrane can maintain a suitable space under the membrane, no bone grafting materials are needed. Titanium reinforcement helps with shaping of membranes and maintaining space under the membrane. However, bone grafting materials can also be used under the membrane to ensure proper space for bone regeneration. Nonporous high-density PTFE membranes do not have to be covered and can remain exposed to an oral environment until removed at 30 days or later.

Absorbable membranes

Absorbable membranes deteriorate at different rates depending on the type; some resorb in a few days whereas others take months to resorb. The longer the membrane stays intact the longer time the body has to regenerate bone under the membrane. The last bone to mineralize is the bone located directly under the membrane, which is farthest away from the native bone and closest to the soft tissue. When absorbable membranes are exposed to the oral cavity they degrade much faster than they would if contained under a flap. A membrane that takes six months to resorb in tissues can be gone in 30 to 45 days when exposed to the oral cavity. The absorbable membranes have fewer postoperative complications than non-absorbable membranes and do not require a secondary procedure for membrane removal; therefore, absorbable membranes are more widely used. Root coverage has been tried with absorbable membranes, but success rates vary. One report on long term evaluation of an absorbable guided tissue regeneration membrane for root coverage showed a marked decrease in the amount of root coverage over a two year period from 92% to 59%. Some clinicians recommend absorbable membranes for ridge augmentation, but not for root coverage.