Platelet Rich Plasma in Reconstructive Periodontal Therapy

1.1 Regenerative periodontal therapy The goal of periodontal therapy is to improve periodontal health and thereby to satisfy the patient’s esthetic and functional needs or demands. To achieve this goal, most periodontal treatments aim to reduce probing depths and maintain or improve attachment levels and these parameters are used as surrogates of improved tooth retention. Conventional periodontal therapy includes non-surgical treatment as well as a variety of surgical approaches. In such treatments, histologic analysis revealed that periodontal healing occurs with repair rather than regeneration (Listgarten & Rosenberg, 1979). In repair, long junctional epithelium exists between the treated root surface and alveolar bone (Caton & Greenstein, 1993). However, over the last three decades, the major goal of periodontal therapy has been shifted from repair to reconstruction of periodontal tissues thereby reversing the damage to the periodontium caused by the disease process. “True periodontal regeneration” is the reformation of a functionally oriented periodontal ligament with collagen fibers inserting in both regrown alveolar bone and reformed cementum over a previously diseased root surface. The first evolutionary stage of periodontal regeneration focused on using a variety of bone graft materials. A number of techniques and autogenic, allogenic, xenogenic and alloplastic bone graft materials have been used for regeneration purpose (Brunswold & Mellonig, 1993). Although significant clinical improvements in terms of probing depth reduction, attachment and bone gains were obtained, the results of the histological studies reported that new attachment achieved by bone grafts was usually a result of the formation of long junctional epithelium with slight or no new connective tissue attachment and negligible new cementum formation. Since these techniques have had limited success, more effective regenerative approaches have been suggested that utilize tissue-engineering techniques. The concept of tissue engineering in periodontics began with guided tissue regeneration (GTR), a mechanical approach utilizing nonresorbable or bioabsorbable membranes to regenerate periodontal defects. GTR is a technique in which the placement of an occlusive membrane guides progenitor cells, residing in the periodontal ligament to repopulate the osseous defects in order to form new tooth supporting tissues (Nyman et al., 1982). The evidence, in fact, demonstrated that treatment of twoand threewall intrabony defects with GTR has yielded successful clinical results in numerous studies and could promote