Influence Of Midfacial Sutural Distraction Osteogenesis On The Morphous Development Of Craniofacial Skeletons And Sutures

Part I The possibility of Sutural Distraction Osteogenesis on craniofacial skeleton utilizing trans-facial pinObjective An external fixation retractor was applied on experimental animals to study the method of Sutural Distraction Osteogenesis on craniofacial skeleton. Method Rigid external distractors were fixed on experimental animals. Kirschner wire was penetrated bilateral maxillary bones as force-borne device and a elastic traction of 800g was exerted on them for 20 days. Result 3 dogs survived to predicted observation period. The external fixation retractor had an excellent retention and were not loose. The experimental animals appearances a progressively maxillary antelocation without obvious stationary period . The clinically visible maxillary antelocation could be observed 2～3 days after distraction. Edge-to-edge occlusion relationship appeared 7-8 days after distraction. The occlusal relationship turned into Angle Class II from Angle Class III from then on. The maxillary complex showed parallel anterior displacement and there was no obviously change in the basilar-maxillary angle. Conclusion The external fixation retractor has an excellent retention . The micro surgical trauma, suitable tractive force and excellent distraction effect make the experiment can exactly mimic the process of treating midfacial hypoplasia clinically.Part II Influence of midfacial sutural distraction osteogenesis on the development of craniofacial skeletonsObjective To smmarize the effect of midfacial sutural distraction osteogenesis on the development of craniofacial skeletons. Method 800g force was exerted on experimental animals for 20 days, then retained for 20 days. After that, the animals were fed for additional 80 days until they were sacrificed. ResultsCompared the experimental dogs with the NC dogs: the length of facial cranium, the length of mandible and the length of A-B was longer than that of the latter significantly ; posterior skull width less than that of the latter; the length of cerebral cranium increased significantly after distraction but the difference diminished with time continuation. Conclusion The SDO technique can significantly prolong the maxillary complex. There is a different growth tendency between the length of facial cranium and length of cerebral cranium, and maybe the recovery of length of cerebral cranium is the main cause of relaps;he length of mandible increase rapidly accompanied with anterior displacement of maxilla and keep in coordination with development of craniofacial length. The external fixation retractor inhibit obviosly the young animal's development of cranium width.Part III Influence of midfacial sutural distraction osteogenesis on the histological reconstruction of craniofacial sutures and mandibular condyle. Objective To explore the effect of midfacial sutural distraction osteogenesis on the reconstruction of craniofacial sutures and mandibular condyle by general observation and quantitative research on them. Method Image analytical technique was introduced to analyse the sutures and mandibular condyles. Results Compared the experimental group with the normal control group: the width of sagittal suture and frontal suture was significantly less than that of the latter; the width of around maxillary sutures larger than that of the latter; the cell density of sagittal suture and frontal suture was significantly less than that of the latter; the thickness and cell area of condylar cartilage was larger than that of the latter; Conclusion The cellular changes of craniofacial sutures and mandibular condyle vary from regression to active reconstruction with different locations by Long-term influence of SDO technique.