4,10,11 Autogenous bone has osteogenic potential, as it contains cells that participate in osteogenesis.4,12 Moreover, autografts are bioabsorbable (they relatively are eventually replaced by the patient��s own bone),10 nonallergenic (they cause minimal tissue reaction without an immunological reaction),4,10 easy to handle, and not costly.13 Rapid revascularization occurs around autogenous bone graft particles, and the graft can release growth and differentiation factors.4,14 Although autogenous bone grafts present some disadvantages, such as the need for secondary surgical sites and resulting additional surgical morbidity,10,15 they can be minimized by using intraoral harvested bone.15 The use of the latter graft material is however limited by the restricted donor sites in the oral cavity for extensive grafting.

4,15 In order to support barrier membranes, prevent collapse, and promote bone formation, GTR has often been combined with the placement of bone grafts or bone graft substitutes. The effectiveness of the combined procedure for treating periodontal intraosseous defects has been evaluated in comparison with the use of GTR alone in many studies, which have shown contradictory results.16�C19 Some clinical studies have demonstrated better clinical results and bone fill with the combined procedure,16,19 whereas no significant difference was found between the treatments in other studies.17,18 Moreover, few experimental studies have reported successful alveolar ridge augmentation by combining autogenous mandibular bone grafts with nonresorbable and resorbable GTR membranes.

20,21 One clinical study has shown that the combination of an autogenous bone graft and a bioabsorbable GTR membrane is effective for treating three-wall periodontal defects.22 Data from both clinical and histological studies suggest that periodontal regeneration occurs following treatment with autogenous bone grafts.23�C25 However, a 12-month clinical study has shown that autogenous cancellous bone from the jaw compared with open flap debridement is not suitable for treating intrabony periodontal defects.26 Note-worthily, an autogenous cortical bone (ACB) graft, sourced from the surgical site adjacent to the intraosseous defect, is advantageous as it prevents the need for a second surgical site while treating intraosseous periodontal defects.

Further, the use of a physical barrier in addition to an ACB graft may enhance the regenerative outcome. The aim of this clinical trial was to evaluate the additional benefit of using GTR in conjunction with ACB grafting versus ACB grafting alone for the regenerative treatment of intraosseous periodontal defects. MATERIALS AND METHODS Experimental design Two different approaches to treat intraosseous periodontal defects were compared Drug_discovery by using a split-mouth, randomized, controlled design. Randomization was conducted before surgery according to the flip of a coin.