This study was done based on the principle of early repair of mandible defect after firearms wound. The results showed that the delayed one stage reconstruction could be used to repair of maxillofactial defect caused by firearms wound, using vascularized graft was supperior to the free bone graft alone. The latter is not suitable for the repair of maxiUofacial firearms defects in early stage.

Objective: To develop a bio-multi-function impact device for the study of maxillofacial impact injury . Methods: This device, driven by high-pressure nitrogen air, was consisted of impact unit, laser speed-measure meter, trigger unit, operation platform and information record unit. Results: A new type of bio-multi-function impact device was manufactured with the function of the impact and project. The impact velocity is from 3 to 40 m/s and can be adjusted. The muzzle velocity of the projectile can reached from 300 to 1 500 m/s and also can be adjusted according to the demand of the experiments. It can record exactly multi-line biomechanic signals. Conclusion: The device is stable and suitable for the study of impact and projectile injury.

To investigate the mechanism of common carotid artery injury produced by explosion in neck region, and to determine the severity of carotid injury based on the injury of neck and the pressure of blast waves. After the detonation of the blast source at different distances, the injuries to rabbits' neck and carotid artery were examined, and the pressure of the blast waves to both skins and common carotid artery were measured with PVDF(polyvinylidene fluoride)sensors and oscilloscope. The endothelium of the injured carotid artery desquamated and micro thrombus formed on the arterial walls the after injury. Disruptions in the tunica media might account for pseudo aneurysm formation. These results offered experimental evidences pseudo aneurysm and thrombus formation in the carotid artery after an explosion in the neek region.

Objective:To observe the effects of bone marrow stromal cells(BMSCs)/coral composite strengthened by titanium mesh in the repair of mandibular defects. Methods:The rabbits' BMSCs were cultured and induced in vitro, and then were combined with coral to form the BMSCs/coral composite, which were implanted into the left mandibular defect in the size of 15 mm?8 mm in 16 rabbits. Titanium mesh was used to strengthen and fix the composites. Coral implant was used as the control in the right mandibular defect.Six and twelve weeks after operation, X-ray observation and histological examination were employed to assess the status of bone formation. Results:In the experimental group, new bone formation was found by radiography and the histological examination 6 weeks after operation. 12 weeks after operation woven bone and lamellar bone were observed in the implanted area and the bone defects were repaired, coral was disappeared, titanium was integrated with surrounding bone tissue. In the control group 12 weeks after operation the bone defects were filled by fibrous tissue, coral was disappeared. Conclusion:Titanium /BMSCs/coral composites can repair mandibular defects effectively.

Objective:To establish an animal model in goats for curved mandibular regeneration by distraction osteogenesis(DO).Methods:Four goats were used.Internally installed curved mandibular distractors were activated 6 days after mandibular osteotomy on the mandibular angles or mandibular symphyses at a rate of l mm/d for 25~34 days.The mandibles were examined by roentgenography.Results:The arched defects of the mandibles in the 4 goats were reconstructed by regenerated bone by the end of DO.Conclusion:Internally installed curved distractor may be used for osteogenesis in the repaire of the arched mandibular defects.

Objective: To estabish an animal model with blast injury in maxillofacial region and to study the biomechanical property of the model.Methods: Spherical explosive at different distances was used to make wound in maxillofacial region in dogs. The pressure on tissue at different level, the variation of horizontal acceleration and strain of the mandibular and temporal bone were dynamically measured.Results: About 3.5 cm?3.0 cm soft tissue defect and madibular splintered fracture occurred in maxillofacial region when the spherical explosive exploded on the surface of the dog's face and the animal survived. The pressure on mandible was respectively 3.6%?2.9% of the surface of dog's face when the spherical explosive exploded 0 and 1.00 cm away from the dog's face while the ratio of horizontal acceleration of cranium to mandibular was 1/8?1/6. Splintered fracture occurred in mandible when the mandibular strain was 11 375 ??.Conclusion: The model can be applied as an animal model with blast injuries in maxillofacial region.

Objective: To observe effects of treatment of mandibular fractures with compression or non compression internal fixation. Methods: In the in vivo study mandibular fractures were fixed by compression internal fixation on one side and non compression on other side in 15 dogs and observed radiologically and histologically. In clinical practice 42 patients with 58 mandibular fractures were treated with compression internal fixation, and 56 patients with 78 madibular fractures were treated with non compression internal fixation. Their clinical effects were evaluated by masticatory efficiency test, radiological and clinical observation after operation. Results: Primary bone healing was found histologically in group of compression fixation and bone healing through callus in group of non compression in the dogs. In the patients treated with compression internal fixation bone fracture line disappeared 1 week earlier and masticatory efficiency was heigher than in those with non comprission fixation. Conclusion: Both methods are all effective in the treatment of mandibular fractures. The miniplate is convenient in use and the indication is wide ranging. The compression plate can speed healing of mandibular fractures, but the operation is more strict technically.

To assess the ability of new bone formation with composite human bone marrow stromal cell (HBMSC)/coralline hydroxyapatite(CHA) in vivo. Human bone marrow collected from adult ilium by needle aspiration was cultured in vitro to expand and differentiate the stromal cells. The cells were seeded on CHA discs, then the HBMSC/CHA composites were implanted subcutaneously into athymic nude mice (CHA alone as control). At 4 and 8 weeks after implantation, the effectiveness of bone formation was evaluated by means of gross and histological observations. The results showed that HBMSC/CHA composite could form bone tissue in vivo, in which a small amount of HBMSC could be used as seed cells in bone tissue engineering, and CHA could be used as a kind of scaffold.

Objective To design a more reasonable method by comparing three existing injury severity scores for evaluating maxillofacial injury severity according to its features by retrospective analysis. Methods Nine hundred and eighty-four cases with maxillofacial trauma (≤30 days before hospitalization) selected from 1 159 cases were stratified by the number of fractures and the sites of trauma. The injury severity was evaluated with ISS, RFISS and MISS respectively. The results of ISS/RFISS/MISS were compared and analyzed with SPSS software. Results MISS could accurately differentiate single from multiple facial injuries. It was more meaningful for evaluating different sites of facial injury compared with ISS and RFISS. Conclusion MISS can be used to evaluate maxillofacial injury objectively and accurately.

Objective To analyse the characteristics of maxillofacial injuries resulted in different causes. Methods A retrospective review was done of patients admitted to the Stomatology Hospital of Fourth Military Medical University from January, 1996 to July, 2003. Data was grouped by different causes. Results 1 188 patients were reviewed, the majority of victims caused by different causes were males, the ratio of male and female is 3.34∶1. Most industrial and sport injury occurred in men. Traffic accidents were the major cause of the midface fracture and mandibular fracture. While violence was the major cause of pure soft injure and alveolar bone fracture. Conclusions Traffic accidents and violence were the major causes of facial injury. The facial injury caused by traffic accidents, industrial accidents and fall was more serious than those caused by other causes. More emphasis should be put on the prevention and treatment of these injuries to minimize the maxillofacial malformation.