Comparison of two different methods of rapid expansion combined with maxillary protraction in the treatment of skeletal class Ⅲ malocclusion / 中华口腔医学杂志

Objective: To compare the effect of bone-anchored versus tooth-borne rapid palatal expansion (RPE) combined with maxillary protraction in the treatment of skeletal class Ⅲ patients with maxillary hypoplasia. Methods: Twenty-six skeletal class Ⅲ patients with maxillary hypoplasia in the late mixed or early permanent dentition were selected. All the patients underwent RPE combined with maxillary protraction in the Department of Orthodontics, Nanjing Stomatological Hospital, Medical School of Nanjing University from August 2020 to June 2022. The patients were divided into 2 groups. Thirteen patients were enrolled in the bone-anchored RPE group [4 males and 9 females, aged (10.2±1.7) years] and the others were in the tooth-borne RPE group [5 males and 8 females, aged (10.1±1.0) years]. Ten sagittal linear indices [Y-Is distance (the distance from the incisor edge of the maxillary incisor to the vertical reference axis), Y-Ms distance (the distance from the mesial contact point of the maxillary first molar to the vertical reference axis), the relative distance between the maxillary and mandibular molars, overjet, etc.], 6 vertical linear indices [PP-Ms distance (the distance changes from Ms to the palatal plane), etc.] and 8 angle indices [SN-MP angle (the upper external angle of the intersection of the sella-nasion plane and the mandibular plane), U1-SN angle (the lower internal angle of the intersection of the long axis of the maxillary central incisor and the sella-nasion plane), etc.] were measured on the cephalometric radiographs before and after the treatment. Six coronal indicators (the inclination of the left and right first maxillary molar, etc.) were measured on cone-beam CT images before and after the treatment. The proportion of skeletal and dental factors in the changes of overjet were calculated. The differences of the index changes between groups were compared. Results: After the treatment, the anterior crossbite were corrected in both groups, and classⅠor classⅡ molar relationship were attained. In bone-anchored group, the changes of Y-Is distance, Y-Ms distance and maxillary and mandibular molar relative distance were (3.23±0.70), (1.25±0.34) and (2.54±0.59) mm, respectively, significantly less than those in the tooth-borned group in which the corresponding changes were (4.96±0.97) mm (t=-5.92, P<0.001), (3.12±0.83) mm (t=-7.53, P<0.001) and (4.92±1.35) mm (t=-5.85, P<0.05), respectively. The change of overjet in the bone-anchored group was (4.45±1.25) mm, significantly less than that in the tooth-borned group (6.14±1.29) mm (t=-3.38, P<0.05). Skeletal and dental factors accounted for 80% and 20% of the overjet changes in the bone-anchored group, respectively. While in the tooth-borned group, skeletal and dental factors accounted for 62% and 38% of the overjet changes, respectively. The PP-Ms distance change in the bone-anchored group [(-1.62±0.25) mm] was significantly less than that in the tooth-borned group [(2.13±0.86) mm] (t=-15.15, P<0.001). The changes of SN-MP and U1-SN in the bone-anchored group were -0.95°±0.55° and 1.28°±1.30°, respectively, significantly less than those corresponding indices in the tooth-borned group (1.92°±0.95°, t=-9.43, P<0.001; 7.78°±1.94°, t=-10.04, P<0.001). In the bone-anchored group, the inclination changes of maxillary bilateral first molars in the left and right sides were 1.50°±0.17° and 1.54°±0.19°, significantly less than the corresponding indices in the tooth-borned group (2.26°±0.37°, t=6.47, P<0.001; 2.25°±0.35°, t=6.81, P<0.001). Conclusions: The bone-anchored RPE with maxillary protraction could reduce the adverse tooth compensation effect, including the protrusion of maxillary anterior incisors, the increase of overjet and mandibular plane angle, and the mesial movement, extrusion and buccal inclination of maxillary molars.

Course of disease and related epidemiological parameters of COVID-19: a prospective study based on contact tracing cohort / 中华预防医学杂志

Objective: To analyze the course of disease and epidemiological parameters of COVID-19 and provide evidence for making prevention and control strategies. Methods: To display the distribution of course of disease of the infectors who had close contacts with COVID-19 cases from January 1 to March 15, 2020 in Guangdong Provincial, the models of Lognormal, Weibull and gamma distribution were applied. A descriptive analysis was conducted on the basic characteristics and epidemiological parameters of course of disease. Results: In total, 515 of 11 580 close contacts were infected, with an attack rate about 4.4%, including 449 confirmed cases and 66 asymptomatic cases. Lognormal distribution was fitting best for latent period, incubation period, pre-symptomatic infection period of confirmed cases and infection period of asymptomatic cases; Gamma distribution was fitting best for infectious period and clinical symptom period of confirmed cases; Weibull distribution was fitting best for latent period of asymptomatic cases. The latent period, incubation period, pre-symptomatic infection period, infectious period and clinical symptoms period of confirmed cases were 4.50 (95%CI:3.86-5.13) days, 5.12 (95%CI:4.63-5.62) days, 0.87 (95%CI:0.67-1.07) days, 11.89 (95%CI:9.81-13.98) days and 22.00 (95%CI:21.24-22.77) days, respectively. The latent period and infectious period of asymptomatic cases were 8.88 (95%CI:6.89-10.86) days and 6.18 (95%CI:1.89-10.47) days, respectively. Conclusion: The estimated course of COVID-19 and related epidemiological parameters are similar to the existing data.

Post-traumatic Stress Disorder,Social Support,and Quality of Life in Patients with Spinal Cord Injury / 中国医学科学院学报

Objective To explore the relationship among post-traumatic stress disorder(PTSD),social support and quality of life in patients with spinal cord injury(SCI)after a long recovery in China and investigate the factors influencing the quality of life. Methods In this cross-sectional study,206 SCI patients who were hospitalized in 9 hospitals were enrolled.Data collection was performed using general information,the Post-Traumatic Stress Disorder Checklist-Civilian version,the social support scales,and the World Health Organization Quality of Life-Abbreviated version.The data were statistically analyzed using

Study of mandibular anterior alveolar bone thickness in subjects with different facial skeletal types / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To study the association of vertical facial skeletal types and sagittal facial skeletal types with anterior alveolar bone thickness.</p><p><b>METHODS</b>Among 168 cases with malocclusion in early permanent dentition stage, 93 patients were male and 75 patients were female. All patients (aged 10-14 years) were divided into 9 groups by different facial skeletal types, mandibular anterior alveolar bone thickness in patients' lateral cephalometric films were measured. ANOVA were performed to measurement results with the SPSS 13.0 statistical software.</p><p><b>RESULTS</b>Though sagittal facial skeletal types were the same, there were significant differences between different vertical facial types groups. The order was low-angle group, average-angle group and high-angle group according to the size. A high-angle individual often had a thin anterior alveolar bone while a low-angle individual often had the opposite morphology character. There was no statistical significance between skeletal type I, II and III. But group of skeletal type III also had a thin alveolar bone thickness which had no significant difference with high-angle group. Low-angle group III had no significant difference with average-angle group I and II in alveolar bone thickness.</p><p><b>CONCLUSION</b>Sagittal facial skeletal types have little influence on anterior alveolar morphology, but the vertical facial skeletal types have strong connection with anterior alveolar bone thickness.</p>

Study on prevalence and correlation factors of bronchial asthma in Zaozhuang area, Shandong province / 中华流行病学杂志

<p><b>OBJECTIVE</b>To study the prevalence of asthma and its correlated factors in Zaozhuang area in 2003, to provide a basic consideration for prevention/treatment and control policy.</p><p><b>METHODS</b>6 points were selected by stratified-clusterd-random sampling with a total of 16,725 persons expected, but only 10,610 subjects investigated.</p><p><b>RESULTS</b>In this survey, 128 asthma cases were identified with a overall prevalence of 1.21%. The prevalence for children was 2.02%, and for adult was 0.90% with the former significantly higher then the latter (chi(2) = 21.39, P < 0.01). Rates for male and female were 1.08%, 1.32% with a ratio of 1:1.22. For 77.97% of children with asthma. The initiative age of asthma was before 7 years old among children while among 36.23% of the adults, it was before 15 years of age. Correlation analysis showed that upper respiratory tract infection (OR = 17.81, 95% CI: 12.25-25.89), cold air exposure (OR = 3.43, 95% CI: 2.41-4.90), stimulation through cooking and by harmful gases (OR = 2.56, 95% CI: 1.80-3.63), allergic materials (OR = 2.74, 95% CI: 1.80-4.17) were main inducing factors. 65.63% of the asthma cases having had history of allergic disease while 25.78% having had family history with the OR of allergic history and family history as 21.69 vs. 73.96.</p><p><b>CONCLUSION</b>The epidemic status of bronchial asthma was serious, with an assumption that asthma cases might have reached the number of 43 thousand in Zaozhuang area.</p>