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Objective To understand the seasonal and etiological characteristics of the epidemic situation of cluster fever in Pudong New Area, Shanghai, and to provide a scientific basis for the formulation of prevention and control strategies. Methods The epidemic data of cluster fever in Pudong New Area of Shanghai from 2013 to 2021 were collected, and the data were analyzed by concentration degree and circular distribution methods. Results From 2013 to 2021, there were 109 cases of cluster fever reported in Pudong New Area, with primary schools reporting the most cases, 77 cases (70.64%). The M value was 0.59. Circular distribution results showed that angle dispersion index r value was 0.54, the average angle was 357.32°, and the average angle of Rayleigh’s test Z value was 32.07. The peak day was December 28, and the peak period was from October 25 to March 3 of the following year. The cluster of fever in Pudong New Area was mainly caused by influenza virus. Most cases were single pathogen infection, and some were double pathogen infection. Influenza A virus had the highest detection rate in both single pathogen infection and double pathogen infection. Conclusion Primary schools are the focus of prevention and control of the cluster of fever in Pudong New Area. The epidemic situation of cluster fever has a strong seasonal characteristic, and the peak of incidence is from late October to early March of the next year. Respiratory pathogens such as influenza virus are the main causes of the epidemic situation.
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Objective: To study the 3D positional changes occurring to anchor molars of 37 patients treated with MBT appliance. Methods: Thirty seven patients who needed maximum upper molar anchorage were divided into two treatment groups at random, group Ⅰ was comprised of 19 patients whose anterior teeth were retracted en masse, and group Ⅱ included 18 patients whose anterior teeth were retracted by two step. All the patients were treated with MBT appliance and headgear. Dental casts recorded before and after treatment were analyzed by YM 2115 three dimensional digitizer and related software. The changes of anchor molar tip,torque and rotation were compared between the two groups. Results: During the treatment, average anterior movement of the upper first molars was 4.53 mm, average extrusion of the upper first molars was 1.53 mm; the crown of the upper first molar tipped forward (6?4)?,torque buccally (3?6)?,and mesiolingually rotated 3.15?; In en mass group, the crown of the upper first molar tipped more mesially than the two step group, and the difference was statistically significant. Conclusion:Almost all the upper first molars showed the tendency to rotate and tip mesially and torque bucally; there was no statistically significant difference between the two treatment groups when upper molar positional changes were concerned except for the mesial tip of the crown.
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<p><b>OBJECTIVE</b>To determine the agreement between two-dimensional radiograph and three-dimensional CT in the evaluation of the secondary alveolar bone grafting.</p><p><b>METHODS</b>Nine complete cleft lip and palate patients (8 UCLP, 1 BCLP) at least 6 months post secondary alveolar bone grafting were selected. The mean age of the patients was 15.5 years with a range of 12 to 26 years. Occlusal radiographs were taken and the interdental septal height was determined using Bergland criteria. There were 2 type I sites, 2 type II sites, 5 type III sites and 1 type IV site. All the patients had undergone CT scan of the cleft within two months after the radiograph was taken. The plane of scan was parallel to the occlusal plane. Cuts of 2 mm were taken from the infraorbital rim to the gingival third of the crown of the teeth. Three-dimensional reconstruction was performed.</p><p><b>RESULTS</b>The interdental septal height on the occlusal radiograph was conformed by the CT scan. Labial and palatal notch was found on CT scan at two grafting sides.</p><p><b>CONCLUSIONS</b>The study provided some evidence to support the continued cautious use of anterior occlusal radiograph in the evaluation of bone-graft success before the orthodontic treatment. When the X-ray examination is not in line with the clinical examination, CT scan is indicated.</p>