Objective:To understand the correlation of different ultrasound characteristics with thyroid cancer, and evaluate the effect and safety of different surgical strategies in pathological suspected cancer and highly suspected cancer by pure ultrasound.Methods:The clinical data of 679 patients (787 thyroid nodules) underwent thyroid surgery from August 2016 to December 2019 in Beijing Daxing District People′s Hospital were retrospectively analyzed, including ultrasound characteristics (echo, margin, form, ratio of tall to wide, calcification), surgery data (operation time, surgical strategies, whether the second surgery), recovery process (whether combined with secondary injury, including hoarse voice and choking on drinking water; drainage tube retention time and postoperative drainage), pathological examination results (pathological types, whether included parathyroid gland in the submitted specimen and whether lymph node metastasis). The effect and safety were compared between dissection and non-dissection of central group lymph nodes in pathological suspected cancer patients and highly suspected cancer by pure ultrasound patients.Results:Among the 787 thyroid nodules, 316 nodules (40.2%) were malignant nodules, including 308 papillary carcinomas; 471 nodules (59.8%) were benign nodules. The rates of low echo, unclear margin, form irregularity, ratio of tall to wide >1 and microcalcification in malignant nodules were significantly higher than those in benign nodules: 90.5% (286/316) vs. 38.9% (183/471), 52.5% (166/316) vs. 11.5% (54/471), 53.8% (170/316) vs. 11.5% (54/471), 30.4% (96/316) vs. 5.5%(26/471) and 65.5% (207/316) vs. 8.7% (41/471), and there were statistical differences ( P<0.01). Among 26 patients with pathological suspected cancer, there were no statistical difference in operation time, drainage tube retention time, postoperative drainage, surgical complications and paraffin pathology result between patients with dissection of central group lymph nodes (17 cases) and patients without dissection of central group lymph nodes (9 cases) ( P>0.05); the patients with dissection of the central group lymph nodes were all proved to be cancer by paraffin pathology examination. The highly suspected cancer by pure ultrasound was in 57 cases, there were no statistical difference in operation time, drainage tube retention time, postoperative drainage, choking on drinking water or hoarse voice between patients with dissection of central group lymph nodes (23 cases) and patients without that dissection (34 cases) ( P>0.05); the incidence of parathyroid gland in the submitted specimen and malignant rate of paraffin pathology result in patients with dissection of central group lymph nodes were significantly higher than those without that dissection: 39.1% (9/23) vs. 2.9% (1/34) and 30.4% (7/23) vs. 8.8% (3/34), and there were statistical differences ( P<0.01 or <0.05). Conclusions:Thyroid ultrasound characteristics have important predictive value. It is recommended to clean central group lymph node in most cases of pathological suspected cancer; while when highly suspected cancer by pure ultrasound happens, it is recommended to clean lymph node only when lymph node metastasis is highly suspected.

Objective:To comparatively evaluate the scan time and the accuracy of maxillary full-arch scans using four intraoral scanners (IOS) on conditions of the intraoral head-simulator and the hand-held model, and to evaluate the influence of different scanning conditions on digital scan.Methods:A upper dental arch model with melamine-formaldehyde resin teeth and silica gel gingiva that could be fixed on a head simulator was scanned with an optical scanner (ATOS Core) in order to obtain the standard tessellation language dataset as reference. Intraoral scans were performed on the model fixed on the head simulator by three researchers with four IOS [A: TRIOS 3; B: CS 3600; C: CEREC Omnicam; D: iTero]. For each scanner and each researcher, six scans were performed, to obtain the datasets as the head simulator group. And another six scans with each of the four intraoral scanners were performed by each researcher on the hand-held model to obtain the STL datasets as the hand-held group. The scan time were recorded for each scan. In the Geomagic Wrap software, the digital models were trimmed with only the teeth information retained and supreimposed by best fit alignment function and compared to obtain the root mean square (RMS) values of the discrepancies by three-dimensional compare function. The test datasets of each group were compared with the reference dataset for trueness. The six test scanning datasets with the same scanner of the same researcher were cross compared for precision. Mann Whitney U test was used to statistically analyze the difference values of the scan time, trueness and precision of the same intraoral scanner between head simulator group and hand-held group. Results:Compared to the hand-held group, the scan time of A [142(82) s] and D [119(52) s], which two IOS both with handle, were longer in head simulator group [A: 98(28) s; D: 85(22) s] ( P<0.01). However there were no significant differences between the two groups for scan time of IOS B and C ( P>0.05). For full-arch scan accuracy (trueness and precision), there were no significant differences between the two groups of IOS A and B ( P>0.05), while the trueness of C ( P<0.05) and the precision of D ( P<0.01) were better in head simulator group [C: 112(38) μm; D: 43(13) μm] compared to hand-held group [C: 135(47) μm; D: 53(18) μm]. However, there were no significant differences for the precision of C ( P>0.05) and the trueness of D ( P>0.05). Conclusions:The scan time and the accuracy of full-arch digital scans with different IOS may be effected by the scan conditions. For in vitro study of intraoral scanning, head-simulator can simulate the intraoral environment of the real patient to some extent. Meanwhile, the position of the dentist and the patient, and also the limited intraoral space during intraoral scanning are also simulated.

Objective:To comparatively evaluate the accuracy and the scan time of three full-arch scan strategies on the head-simulator, to explore a full-arch scan strategy with better clinical operability and high accuracy.Methods:A cross-controlled study design was used. A model with melamine-formaldehyde resin teeth and silica gel gingiva of an upper dental arch which can be fixed on a head simulator was scanned with an optical scanner (ATOS Core) in order to obtain the standard tessellation language (STL) dataset as reference. Intraoral scans were performed on the model fixed on the head simulator with four intraoral scanners (IOS) [A (TRIOS 3), B (CS 3600), C (CEREC Omnicam), D (iTero)]. The STL datasets were obtained from each of the four different IOS systems by using three scan strategies (scan strategies 1, 2 and 3 were composed of 10, 5 and 7 paths respectively) all by one attending doctor with 3 years of intraoral scanning experience. For each scanner and each scan strategy, nine scans were acquired. And the scan time was recorded for each scan. Following the scan strategy, the scan path was completed to obtain a full-arch digital model, and the scan time was recorded as full-arch scan time. Complementary scans were performed to fill the missing image, and this scan time was recorded as complementary scan time. The total scan time was obtained by adding full-arch scan time and complementary scan time. Through the Geomagic Wrap software, the three-dimensional (3D) models were overlaid by best fit alignment function and compared to obtain the root mean square values of the discrepancies by 3D compare function. The intraoral scanning datasets were compared with the reference for trueness. The nine intraoral scanning datasets were cross compared with same scan strategy and same intraoral scanner for precision.Results:There were no significant differences among the three scan strategies for trueness ( P>0.05), while the differences among the three scan strategies for precision were affected by difference IOSs ( P<0.05), and only scan strategy 3 showed the highest precision with all the four IOS. The full-arch scan time of scan strategies 1, 2 and 3 were (130±24), (72±17) and (90±19) s respectively ( P<0.05). For complementary scan time, scan strategy 2 [(50±24) s] took longer time than scan strategy 1 [(26±18) s] and scan strategy [(25±21) s] ( P<0.05), while no significant differences between the latter two ( P>0.05). For total scan time, scan strategy 1 [(156±31) s] took longer time than scan strategy 2 [(122±30) s ] and scan strategy 3 [(115±29) s ] ( P<0.05), while no significant differences between the latter two ( P>0.05). Conclusions:Full-arch scanning on the head-simulator with scan strategy 3 which can obtain scanning datasets with high accuracy, was more convenient to operate and took shorter scan time, and is generally suitable for intraoral scanners commonly used in clinic.

Stomatognathic system rehabilitation (SSR) is an important component of dental implant therapy, involving multiple disciplines and factors. This article focuses on the importance of clinical issues, such as mandibular position, vertical distance, occlusion and temporomandibular joint in SSR, in order to provide reference for dentists in clinical diagnosis and treatment.

Corona virus disease 2019 (COVID-19) patients with trauma are at high risk of venous thromboembolism (VTE), which must be taken seriously in the therapeutic processes. Hypercoagulable state is induced by 2019 novel coronavirus (2019-nCoV) in many ways, such as increasing the level of inflammatory factors and fibrinogen, and inducing endothelial cell injury. The venous wall injuries from trauma and operation directly or indirectly trigger off the exogenous coagulation pathway and the microcirculation can be damaged at the same time, which may initiate the exogenous pathway of VTE. Immobilization of limbs and forced bed rest during the treatment of traumatic patients will slow venous blood flow. Chronic non-communicable diseases such as diabetes in the elderly were independent risk factors for VTE. Furthermore, the persistent fever, severe lung disease, respiratory failure, sepsis and invasive technology application add the risk of VTE and the difficulty of treatment. In order to help effective prevention VTE of for COVID-19 patients with trauma, the authors put forward relevant technical suggestions for prevention and nursing of VTE to provide basis for nursing work during pandemic of COVID-19.

Objective To understand the current situation of nutrition literacy of primary and secondary school students in Shijingshan District of Beijing, and analyze its influencing factors, and to put forward targeted suggestions for improving the students’ nutrition literacy and promoting their healthy growth. Methods A multi-stage stratified cluster sampling method was used to select 2480 primary and secondary school students and their parents from 5 primary schools, 3 middle schools and 1 high school in Shijingshan District. The multivariate logistic regression model was used to analyze the factors influencing the attainment rate of nutrition literacy. Results The median score of nutrition literacy of 2480 primary and secondary school students from grades 1 to 12 was 77.86 (in hundred-mark system), the quartile range (IQR) was 16.96, and the attainment rate of nutrition literacy was 42.46%. The cognitive level (45.12%) was higher than the skill level (41.20%) among students from grades 3 to 12. In terms of skills, the attainment rate of food preparation was the lowest, at 30.38%. The scores of nutrition literacy of girls were higher than those of boys, and the scores of primary school students were higher than those of secondary school students. Students with different levels of caregiver’s education, family income, and family food environment had different scores of nutrition literacy, and the differences were statistically significant (P<0.05). Multivariate logistic regression analysis showed that the attainment rate of nutrition literacy was closely related to student’s gender and study stage, caregiver’s education level, and family food environment. Conclusion The nutrition literacy of primary and secondary school students in Shijingshan District still needs to be improved, especially in the aspect of skills. Targeted nutrition education should be carried out.