Guided tissue regeneration (GTR) aims to regenerate lost periodontal tissues by using barrier membranes to selectively prevent the migration of epithelial and gingival connective tissue cells to the root surface, allowing periodontal ligament cells to repopulate the area. The document discusses the history and development of GTR, the biological basis and concept behind using barrier membranes, characteristics of ideal GTR membranes, indications and contraindications for GTR, and outcomes from studies applying GTR in treating periodontal defects.