Fig. 4

Histologic view after 8 weeks of healing showing – (a) control group; defect spaces were filled by the overlying soft tissues and dense fibrous tissues. (b) Collagen membrane group; the collagen membrane showed clear reduction in structural integrity as resorption had taken place. New bone was integrated with the collagenous network of the membrane and gradually occupied the space in which the membrane existed previously. (c) Bone graft group; Mature new bone formation could be observed. The superficial layer of bone graft particles were surrounded by fibrous tissue and the regenerated bone was slightly below the original height of native bone. (d) Bone graft with collagen membrane group; new bone surrounded the bone graft particles, which were interconnected to form complete closure of the defect space. New bone formation extended from the native bone at the defect perimeter into the covering membrane that was closely adapted to the native bone. X40 magnification view, Trichrome staining