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 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.

Objective: To study the injury characteristics of blast injury in maxillofacial region wounded by spherical explosive. Methods: Spherical explosive was used to wound maxillofacial region in rabbits , after gross observation of the trauma , bone tissue specimens were collected from 0.5 or 1.0 cm to the boundary of wound 6 hours, 3 and 7 days after wounding respectively, the samples were prepared and stained with HE and modified Mallory's trichrome staining and observed under light microscope . Microcirculation in wounded bone was studied by ink injection and observed in ground bone sections. Results: No changes were found 6 hours after injury. Inflammatory infiltration were found 3 days after injury.Osteonecrosis was observed 7 days after injury, the structure of bone beyond 0.1 cm of the wound was found to be normal and restoration of bone was observed. Conclusion : Pathological changes of mandible injured by spherical explosive are similar to those of usual fracture except that the wound of blast injury is seriously polluted.

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.

砄bjective: To study the cause,clinical characteristics and treatment of zygomatic complex fractres(ZCF). Methods: Medical records of 79 cases with ZCF and followed up for 3 months to 2 years were reviwed and analysed. Reduction and cosmatic outcome were assessed by clinical evaluation and postoperative images. Results: Of the 79 patients, 87.3% were male, with the peak incidence in the age group from 20 to 40 years old(73.5%). 58.2% were due to traffic accidents, 15.2% to assalts. Incidence of malar asymmetry, enophthalmos, diplopia,limited mandiblar movement and malocclusion were 83.5%,24.1%,19.0%, 60.8% and 35.4% respectively. Of the nerve disturbances, 41.8% of the infraorbital and 13.9% of the facial nerve were involved. For the treatment the most freqently used approach was the coronal incision in combination with the maxillary vestibular incision(30.4%), followed by coronal incision alone(22.8%). 40.5% of the patients were treated by rigid internal fixation with titanium miniplates alone or combined with wire fixition(20.3%). All patients but five regained satisfactary facial appearance. Three patients still showed slightly post surgical enophthalmos and diplopia at a 6 month follow up. All of the patients with malocclusion regained their functional occlusion after treatment. Conclsions:A variety of techniques can be used in the treatment of ZCF. Among them the coronal incision in combination with other incisions or alone and rigid internal fixation can produce a satisfactary outcome.

Objective: To study the treatment methodology of postoperative disostosis of maxilla in the patients with cleft palate by orthognathia. Methods: 10 cases (6 males and 4 females) of postoperative dysostois of maxilla in the patients with cleft palate were treated by orthognathia. Operation manners and orthodontic treatment were determined by orthodontists and surgeons before treatment. Orthodontic treatment included upper arch expansion, teeth alignment, leveling the Spee's curve etc. Operation on single jaw or double jaw, or extraction of one anterior tooth to decrease lower dlental arch and to coordinate with the upper jaw forward was conducted according to individual situations. Adjustment of intercuspids relation was conducted after operation. Results: In all the 10 cases discrepancy of upper and lower jaws were resolved, profiles of the faces were improved significantly, dental arch symmetry, physiological overjet and overbite were achieved. Conclusion: Orthognathia is effective in the treatment of postoperative dysostosis in the patients with cleft palate.