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.

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 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.

Objective: To observe collagen synthesis in the different phase of distraction osteogenesis(DO) in alveolar cleft.Methods:8 dogs were used to make experimental model of alveolar cleft and underwent the closure of the cleft by distraction osteogenesis.The animals were sacrificed on day 0, 14, 28 and 63 after completion of DO respectively. The samples were examined by histological observation and the expression of typeⅠ,Ⅱ,Ⅲ collagen was studied by immunohistochemistry staining. Results:On day 0, a lot of type Ⅲ collagen fibers were observed in the distraction area. On day 14, there was trabecula bone, collagen Ⅰexpression was stronger than collagen Ⅲ. On day 28, trabecula bone developed into network-like structure with type Ⅰ collagen expression. On day 63,lamellated bone with type Ⅰ collage expression filled the distraction area. No obvious expression of collagen Ⅱ was observed.Conclusions:The formation of new bone is mainly intramembrane osteogenesis along the distraction vector.

Objective: To investigate the distraction osteogenesis technique in correction of severe retro-maxillary deformity following the repair of cleft palate. Methods:10 patients were included in the study. Orthodontic treatment was used as a regular procedure before operation. Distraction osteogenesis technique was used to correct the deformity and malocclusion. 4 of patients applied with the external distractor and others with internal distractor. Latency period was 7 days. Distraction rhythm is 0.8~1 mm/d,2~4 times/d. Consolidation period was 8~12 weeks. Orthognathic surgery was done after distraction finished when necessary. Results:The treatment process was smooth and no severe complication occurred. The maximum of distraction distance is 22 mm, and the minimum of distraction distance was 15 mm. No malunion or ununion occurred in all 10 patients. All the patients were satisfied with the results. Conclusion:Distraction osteogenesis is more suitable for correction of severe retro-maxillary deformity following the repair of cleft palate. Bone transplantation is unnecessary during the operation process with easier handling and lower risk.

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.

Objective To investigate the prevalence of cytotoxin associated gene(cagA)and vacuolating cytotoxin gene(vacA)subtypes of Helicobacter pylori(H.pylori)in patients with upper gastrointestinal disease in Shijiazhuang area,and to assess the relationship between cagA,vacA subtypes and H.pylori related gastrointestinal disease.Methods Totally 55 H.pylori strains were isolated from patients with chronic gastrointestinal disease in Shijiazhuang area.Bacterial DNA from all these strains was extractedThe prevalence and genetic diversity in cagA 3′ region,vacA signal sequence and middle-region alleles were studied by the technique of polymerase chain reaction(PCR).Results In Shijiazhuang area,H.pylori cagA positive rate was 89.1%(49/55);cagA positive rate was not significant ly different between chronic gastritis and peptic ulcer(?~2=0.376,P=0.540).There were three vacA subtypes,including s1a/ m2 90.4%(47/52),s1a/ m1b-m2 5.8%(3/52)and s1a/ m1b 3.8%(2/52).The vacA s1a/m2 subtype showed no significant difference between chronic gastritis and peptic ulcer(?~2=0,P=1.000).Conclusion cagA~+and vacA s1a/m2 subtype of H.pylori are predominant in patients with upper gastrointestinal disease in Shijiazhuang area.There is no relationship between cagA,vacA subtypes and H.pylori related gastrointestinal disease.

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.

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.