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ObjectiveTo identify the rate， population characteristics， and vaccination history of repeat infections among previously infected people in the current epidemic based on the rate of repeat infection and population characteristics of different mutant strains at different times in Pudong New Area of Shanghai， and to provide reference for the prevention and control strategies of novel coronavirus repeat infections. MethodsA total of 9 250 investigated subjects were randomly selected from the new cases of asymptomatic infection and confirmed cases reported by Pudong New Area from March to May 2022. The investigation mainly focused on demographic characteristics， nucleic acid or antigen test results， and symptoms after infection. The repeat infection rates among different populations were compared， and logistic regression was used to analyze the impact of gender， age， and vaccination status on repeat infections. ResultsThe survey sample of 9 250 people had a response rate of 81.85%. There were 4 043 males （53.40%） and 3 528 females （46.60%）， with a median age of 34 years old （P25， P75： 7， 61）. The overall vaccine uptake rate was 59.44% （4 500/7 571）. In December of 2022， there were 563 cases of repeat infection， with an infection rate of 7.44%. The lowest rate of repeat infection was seen in the 3‒ year-old group （2.86%） and the highest rate in the 30‒ year-old group （12.42%）， with significant differences between different age groups. The repeated infection rate for those who had completed their vaccinations was significantly lower （6.57%） compared to those who had not （7.11%）. The age groups of 3‒ years， 70‒79 years， as well as individuals who completed full vaccination and received booster shots were protective factors against repeat infections. ConclusionThe overall rate of reinfection among the infected in Shanghai during the spring of 2022 was low in the outbreak of the Omicron variant， and the rate of reinfection in the 3‒ year-old group was significantly lower than in other age groups. Completing the full course of vaccination significantly reduces the risk of reinfection. Although the reinfection rate is high in individuals who received booster shots， it remains a mitigating factor compared to those who do not receive the vaccine. It is recommended to continue monitoring reinfections in key populations and further strengthen immunization efforts.
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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>