Objective To construct a finite element analytical model of multiloop edgewise arch wire(MEAW),and study its mechanical characteristics.Methods Three-dimensional(3D) model of dentition-bracket-arch wire was set up in an initial graphics exchange specification(IGES) format complex by Pro/E software.The multiloop edgewise arch wire was spliced on the lower dentition.After dividing the arch wire and brackets with quarter-tetrahedron element method,the model was analyzed by ANSYS(an engineering simulation software).Results The finite element analytical model of multiloop edgewise arch wire was successfully built up.Based on the model,when multiloop edgewise arch wire was subjected to a heavy strength in certain parts(such as tooth 3,4),the anti-force strength on the other brackets(such as tooth 1,2,5,6,7) was not so heavy.The subjected strength was light and soft,especially on the first molar.Conclusion The results suggest that the finite element analytical model of multiloop edgewise arch wire built up in the experiment may be used to study the integrated mechanical characteristics,reveal the orthodontic specialty,and discuss the orthodontic mechanisms of multiloop edgewise arch wire techniques.

Objective QR-DVT 9000 NEWTOM CT, an oral maxillofacial dedicated CT, was applied in the diagnosis of maxillary sinus related diseases. Its value and technique are summarized. Method Patients with maxillary sinus related diseases were scanned and images were reconstructed with QR-DVT 9000 CT. The axial view of reconstructed image was analyzed in sagittal plane, coronal plane and 3-D. Results QR-DVT 9000 NEWTOM CT could display the position, shape and anatomic relationship of maxillary sinus with adjacent structures in sagittal image, coronal image and 3-D image. Conclusion QR-DVT 9000 NEWTOM CT, an oral maxillofacial dedicated CT, is considerably valuable in the diagnosis of maxillary sinus related diseases, and it can guide clinical surgery more effectively than routine X ray examination.

[Objective] To search a reasonable approach to the treatment of nasopharyngeal carcinoma (NC) with traditional Chinese medicine integrated with western medicine. [ Methods ] Seventy - six cases of NC were randomized into Group A and Group B. Group A ( n = 39) was treated with herbs for activating blood and removing blood - stasis, nourishing yin and clearing heat during radiotherapy and herbs for replenishing qi and nourishing yin, generating body fluid, moistening dryness and clearing heat after radiotherapy. Group B ( n = 37) was treated with radiotherapy alone. Short - term therapeutic effect, long - term survival rate, the relief of main symptoms, the reduction of cervical lymph node metastasis and side effect of radiotherapy in the two groups were observed. [ Results ] After treatment, the complete relief (CR) rate was 84.6% and 15.4% and partial relief (PR) rate was 73.0% and 27.0% in Group A and B respectively, the differences being significant ( P

Objective:To observe and compare the radiographs of spiral CT and cone-beam CT (CBCT) in the imaging of temporomandibular joint osteoarthrosis (TMJOA) and to explore the difference between CBCT and spiral CT in detection accuracy so as to provide references for clinical diagnosis and treatment.Methods:A total of 52 patients with TMJOA diagnosed in the Department of Oral and Maxillofacial Surgery, General Hospital of Chinese PLA, from January 2018 to December 2019 were selected. There were 10 males and 42 females, with an average age of 38.6 years (21-70 years). All patients underwent spiral CT and CBCT examinations. Two oral radiologists and two oral and maxillofacial surgeons measured and evaluated the joint spaces and condylar bone lesions of each side of temporomandibular joint. According to the presence or absence of osteoarthrosis, the patients were divided into osteoarthrosis group (92 sides) and non osteoarthrosis group (12 sides). The mean size of joint spaces and the detection rate of lesions were compared between the two groups. SPSS 20.0 was used to analyze the data.Results:There was no significant difference between the measurements of joint space size and joint position in the spiral CT group and the CBCT group ( P>0.05). The mean size of the anterior space and the ratio of the posterior condyle in the osteoarthrosis side were larger than that in the normal side. The linear percentage index was smaller in the osteoarthrosis side than that in the normal side indicating that the position of the posterior condyle in the osteoarthrosis side was deviated. However, the difference was not statistically significant ( P>0.05). Both spiral CT and CBCT showed good consistency in displaying condylar osteopathy. The most common types of condylar osteopathy was surface defect. The detection rates of defects by spiral CT were surface erosion (85.6%, 89/104), articular surface flattening and shortening (82.7%, 86/104), subcortical sclerosis (40.4%, 42/104), osteophyte (40.4%, 42/104) and subcortical cyst (11.5%, 12/104) respectively. The detection rates of defects by CBCT were surface erosion (88.5%, 92/104), articular surface flattening and shortening (86.5%, 90/104), subcortical sclerosis (35.6%, 37/104), osteophyte (41.3%, 43/104) and subcortical cyst (11.5%, 12/104). There was no statistical difference between the two groups ( P>0.05), respectively. Conclusions:Both spiral CT and CBCT showed good accuracies in displaying the osteopathy of TMJOA and the sizes of the joint spaces measured by spiral CT and CBCT were basically the same. Both spiral CT and CBCT could be used as a routine diagnostic method for TMJOA.