Revascularization in Maxillofacial Bone Healing

摘要

Callus formation in fracture healing is initiated by cell proliferation and capillary sprouting from the periosteum, bone marrow and surrounding connective tissues. The purpose of this investigation was to elucidate factors crucial to revascularization, the key event in fracture or bone defect repair. Their delineation could modify current treatment modalities to encourage bone revascularization during the reversible ischemic phase of injury; this would result in enhanced healing and faster recovery. Experimental bony defects were produced in monkeys, rabbits and rats. The principal model was a nonhealing defect drilled through the relatively avascular ramus of the mandible of the rat. Infiltration with fibrovascular tissues, revascularization, and subsequent ossification of the defects was assessed after implantation with plaster of Paris alone, demineralized bone, and ceramic hydroxylapatite particles with various binders such as bovine serum albumin, collagen or plaster of Paris. Revascularization was also studied in specimens from humans where ceramic hydroxylapatite had ben used clinically for mandibular ridge augmentation and in specimens from monkeys where it has been used experimentally with plaster of Paris to achieve more adequate ridge augmentation than can be achieved when hydroxylapatite is wetted with saline. The revascularization and repair of mandibular defects implanted with ceramic hydroxylapatite is clearly promoted by a nonimmunologic foreign body granuloma which aids incorporation of the implant particles.