Essay --

1. Guided bone regeneration (GBR) The concept of GBR was described first in 1959 when cell-occlusive membranes were employed for spinal fusions 105.The terms ‘‘guided bone regeneration’’ and ‘‘guided tissue regeneration’’ (GTR) often are used synonymously and rather inappropriately. GTR deals with the regeneration of the supporting periodontal apparatus, including cementum, periodontal ligament, and alveolar bone, whereas GBR refers to the promotion of bone formation alone. GBR and GTR are based on the same principles that use barrier membranes for space maintenance over a defect, promoting the ingrowth of osteogenic cells and preventing migration of undesired cells from the overlying soft tissues into the wound. Protection of a blood clot in the defect and exclusion of gingival connective tissue and provision of a secluded space into which osteogenic cell from the bone can migrate are essential for a successful outcome. The sequence of bone healing is not only affe cted by invasion of non-osteogenic tissue, but more so by the defect size and morphology. A predictable intraoral GBR approach was developed in the late 1980s and early 1990s; 108-110 (bone augmentation techniques 2007) The survival rates of implants placed in augmented sites with GBR are reported in many publications, survival rates range from 91.7 to 100%. However, there are few data about the success rate of dental implants placed in those areas, according to universally established criteria. This may represent a limit in evaluating the reliability of the GBR technique, because a high implant survival rate may not correspond to a high GBR success rate bearing in mind that an implant can remain stable and osseointegrated even if the total amount of regenerated tissue ... ...nd limitations must also be being considered. Some authors have reported partial relapse of the gained bone. More studies are needed to assess the implant survival in the bone gained by DO versus other augmentation methods, including new bone substitutes and augmentation factors. (Alveolar ridge augmentation for implant fixation: status review zakhary 2012). Determination of what technique should be used, is largely surgeon preference and on the extent of the defect and specific procedures to be performed for the implant reconstruction. It is most appropriate to use an evidenced-based approach when a treatment plan is being developed for bone augmentation cases. (Bone augmentation techniques. 2007)(Clinical outcomes of vertical bone augmentation to enable dental implant placement: a systematic review.2008) (Bone Grafting the Mandible Patrick J. Louis, DDS, MD 2011)