Choice of treatment may depend on the defect depth and configuration. A shallow, narrow 3 wall defect may respond well to open flap debridement while a deep 2 wall defect may need regenerative therapy such as an osseous graft, a membrane or combined membrane and graft treatment. Studies of vertical defect therapy with defects about 4 mm or greater show that similar percent defect fill results are obtained with regenerative therapies. Open flap debridement produces substantially less percent defect fill.