Deviations in palatal region between indirect and direct digital models: an in vivo study.

BACKGROUND: Studies focusing on accuracy of intraoral digital models in the palatal region are scarce. The present study aimed to investigate the influence of different scanning sequences on palatal trueness and to assess deviation and distribution character of trueness in palate. METHODS: Overall, 35 participants accepted three types of procedures to acquire upper digital models. Indirect models digitalised from plaster models were considered as the reference. Two direct digital models were acquired using TRIOS 3 POD intraoral scanners, namely Groups Tr1 and Tr2, wherein intraoral scanning differed in terms of palatal scanning sequences. Based on a modified dental-level superimposition method, 3D measurements of trueness in palate and palatal vault region (PVR) for palatal stable regional superimposition in Groups Tr1 and Tr2, respectively, were performed. Absolute deviations were measured for trueness, while signed deviations were analysed for shape distortion. Colour-coded maps were used for quantitative analysis of deviation distribution pattern. Paired t test was used to analyse differences in palatal trueness between different scanning sequences. One-way repeated-measures analysis of variance and Bonferroni test were used to compare trueness measurements among different superimposition methods. Intraclass correlation coefficient (ICC) was used to verify reproducibility of the proposed method. RESULTS: Palatal trueness in Group Tr1 (118.59 ± 37.67 µm) was slightly less accurate than that (108.25 ± 33.83 µm) in Group Tr2 (p = 0.012 < 0.05). Trueness of PVR in Groups Tr1 (127.35 ± 54.11 µm) and Tr2 (118.17 ± 49.52 µm) did not differ significantly (p = 0.149). Moreover, no significant difference was noted in distortion of the palatal region and PVR in Groups Tr1 and Tr2 (p = 0.582 and 0.615, respectively). A similar pattern of palatal trueness was noted in a majority of participants (22/35). For 3D palatal trueness measurement, there were different applications for different superimposition methods. ICC for the proposed method was > 0.90. CONCLUSIONS: Scanning sequences can affect palatal trueness. Palatal scanning should be initiated at the palatal side of the posterior teeth where the initial scan begins. For 3D PVR superimposition, distal boundary of the selected region should be adjusted mesially whilst referring to intraoral digital models. TRIAL REGISTRATION: The trial has been registered (registration No: R000039467 , Trial ID: UMIN000034617, date of registration: 2018/10/24'retrospectively registered').

Effect of different combinations of bracket, archwire and ligature on resistance to sliding and axial rotational control during the first stage of orthodontic treatment: An in-vitro study / 대한치과교정학회지

OBJECTIVE: This study was performed to explore the effect of different bracket, archwire, and ligature combinations on resistance to sliding (RS) and rotational control in first-order angulation. METHODS: Three types of brackets (multi-level low friction [MLF], self-ligating, and conventional brackets) coupled with four nickel-titanium archwires (0.012, 0.014, 0.016, and 0.018-inch diameter) and two stainless steel ligatures (0.20 and 0.25 mm) were tested in different first-order angulations (0°, 2°, 4°, 6°, 8°, 10°, 15°, 20°) by using an Instron universal mechanical machine in the dry state at room temperature. RS value was evaluated and compared by one-way ANOVA. RESULTS: Under the same angulation, the RS values showed the following order: conventional brackets > MLF brackets > self-ligating brackets. The RS was the highest for conventional brackets and showed a tendency to increase. The RS for MLF brackets coupled with thinner archwires and ligatures showed a similar tendency as the RS for the self-ligating bracket. In contrast, the RS for MLF brackets coupled with thicker archwires and ligatures increased like that for conventional brackets. MLF brackets showed the greatest range of critical contact angles in first-order angulation. CONCLUSIONS: The RS in first-order angulation is influenced by bracket design, archwire, and ligature dimension. In comparison with self-ligating and conventional brackets, MLF brackets could express low friction and rotational control with their greater range of critical contact angles.

Diagnostic value of serum chitinase-3-like protein 1 in chronic liver disease of significant fibrosis and cirrhosis / 中华肝脏病杂志

Objective@#To study the correlation between the level of serum Chitinase-3-like protein 1 (CHI3L1) and the significant liver fibrosis and liver cirrhosis in patients with chronic liver disease, and to evaluate its diagnostic value. @*Methods@#165 patients with chronic liver disease were selected, liver histopathological examination was performed to detect serum CHI3L1 concentration. Four indexes of hepatic fibrosis (type III procollagen, collagen IV, laminin, hyaluronic acid), aspartate aminotransferase/platelet ratio index (APRI) and FIB-4 (fibrosis- 4) scores were based on the pathological findings of liver biopsy and compared the advantages and disadvantages of serum CHI3L1 with other methods for the diagnosis of hepatic fibrosis and liver cirrhosis. A multivariate regression analysis model was created, and receiver operating characteristic curve was analyzed. @*Results@#The level of serum CHI3L1 increased with increase of fibrosis stage and was highest in liver cirrhosis stage. In the period of S0 to 1, the levels of S2 to 3 and S4 were 62.82 (41.40 ~ 87.20), 70.94 (48.47 to 122.60) and 141.06 (78.18 ~ 197.40), and there were statistically significant differences between the groups (P < 0.001). The area under the curve for the diagnosis of significant liver fibrosis was 0.68 (0.60 to 0.77), and 0.74 (0.65 to 0.83) for cirrhosis in CHI3L1. Multivariate regression analysis showed that CHI3L1 was an independent predictor of significant fibrosis and cirrhosis. The combined diagnostic model based on CHI3L1, collagen IV and FIB-4 scores further improved the diagnostic value. The area under the curve for the diagnosis of significant fibrosis and cirrhosis was 0.79 (0.72 to 0.86) and 0.80 (0.73 to 0.87), respectively. @*Conclusion@#CHI3L1 has a good diagnostic value in patients with chronic liver disease with significant fibrosis and liver cirrhosis. The diagnostic model in combination with other markers like Collagen IV and FIB-4 scores could further improve the diagnostic value and is worthy of further study.

Changes in buccal facial depth of female patients after extraction and nonextraction orthodontic treatments: A preliminary study / 대한치과교정학회지

OBJECTIVE: This study was performed to investigate buccal facial depth (BFD) changes after extraction and nonextraction orthodontic treatments in post-adolescent and adult female patients, and to explore possible influencing factors. METHODS: Twelve and nine female patients were enrolled in the extraction and nonextraction groups, respectively. Changes in BFD in the defined buccal region and six transverse and two coronal measuring planes were measured after registering pretreatment and posttreatment three-dimensional facial scans. Changes in posterior dentoalveolar arch widths were also measured. Treatment duration, changes in body mass index (BMI), and cephalometric variables were compared between the groups. RESULTS: BFD in the buccal region decreased by approximately 1.45 mm in the extraction group, but no significant change was observed in the nonextraction group. In the extraction group, the decrease in BFD was identical between the two coronal measuring planes, whereas this differed among the six transverse measuring planes. Posterior dentoalveolar arch widths decreased in the extraction group, whereas these increased at the second premolar level in the nonextraction group. The treatment duration of the extraction group was twice that of the nonextraction group. No differences were found in BMI and Frankfort horizontal-mandibular plane angle changes between the groups. BFD changes in the buccal region moderately correlated with treatment duration and dental arch width change. CONCLUSIONS: BFD decreased in adult female patients undergoing extraction, and this may be influenced by the long treatment duration and constriction of dentoalveolar arch width. However, nonextraction treatment did not significantly alter BFD.

Application of circulating tumor DNA in diagnosis and prognosis of epithelial ovarian cancer / 中华全科医师杂志

In the development of cancer, the DNA fragments of tumor cells enter into the blood circulation to form circulating tumor DNA (ctDNA), which is an indicator for detecting and quantifying tumor mutations. Epithelial ovarian cancer accounts for most of the histological types in ovarian cancer. This article reviews the clinical application of ctDNA in epithelial ovarian cancer, including the early diagnosis, therapeutic effect evaluation after operation and adjuvant therapy, tumor load assessment, dynamic monitoring during the follow-up and the prognosis of patients.

Analysis of clinical treatment of the first case of human infection with H7N4 avian influenza virus / 中华传染病杂志

Objective To report the clinical management of the first case of human infection with influenza A (H7N4) in the world ,and to explore the clinical characteristics and therapeutic regimen of H7N4 infection in humans .Methods A case of confirmed human infection with influenza A (H7N4) virus was hospitalized in the Third People′s Hospital of Changzhou in Jiangsu Province on January 1st ,2018 . The clinical characteristics and treatment were analyzed by reviewing the clinical data and management of the patient ,and compared with the clinical characteristics of human infection with H 7N9 cases .Results The patient was an elderly woman with hypertension ,who had an exposure history of live poultry before onset .The patient had flu-like symptoms including fever , cough and expectoration . The symptoms worsened in the fifth day and presented as respiratory failure and circulatory disturbance .The count of white blood cells ,lymphocytes and platelets counts declined ,while the levels of aspartate aminotransferase and c-reactive protein slightly increased .The levels of creatine kinase and lactate dehydrogenase deformity increased .The pulmonary lesions manifested as exudation and consolidation of both side in a short period of time after the onset . Treatment was initiated according to the epidemiology history , clinical manifestations ,laboratory and imaging characteristics . The primary diagnosis was human infection of avian influenza virus .The patient was treated with oxygen therapy ,antivirus ,anti-infection and short-duration corticosteroids treatment . Early and timely throat swab specimens were tested . The patient recovered and discharged from hospital after active treatment .It was confirmed by the Chinese Center for Disease Control and prevention that the patient was infected with avian influenza A (H7N4) virus ,and no close contact was infected .Conclusions There are many similarities of clinical features between case of human infection with H7N4 and that of H7N9 . The early treatment of neuraminidase inhibitors is recommended according to the diagnosis and treatment of human infection with H 7N9 .In the clinical practice ,the avian influenza nucleic acid should be tested in time to determine the cause of the disease in those patients with suspected viral pneumonia ,especially in those who has an avian contact history .

Reproducibility and repeatability of the determination of occlusal plane on digital dental models / 北京大学学报(医学版)

Objective:To assess the repeatability ( intraobserver comparison ) and reproducibility ( inter-observer comparison) of two different methods for establishing the occlusal plane on digital dental models. Methods:With Angle’ s classification as a stratification factor,48 cases were randomly extracted from 806 ones which had integrated clinical data and had their orthodontic treatment from July 2004 to August 2008 in Department of Orthodontics,Peking University School and Hospital of Stomatology. Post-treatment plas-ter casts of 48 cases were scanned by Roland LPX-1200 3 D laser scanner to generate geometry data as re-search subjects. In a locally developed software package,one observer repeated 5 times at intervals of at least one week to localize prescriptive landmarks on each digital model to establish a group of functional occlusal planes and a group of anatomic occlusal planes, while 6 observers established two other groups of functional and anatomic occlusal planes independently. Standard deviations of dihedral angles of each group on each model were calculated and compared between the related groups. The models with the five largest standard deviations of each group were studied to explore possible factors that might influence the identification of the landmarks on the digital models. Results:Significant difference of intraobserver varia-bility was not detected between the functional occlusal plane and the anatomic occlusal plane ( P>0 . 1 ) , while that of interobserver variability was detected ( P0. 1),while the anatomic occlusal plane’s variability of the intraobserver was sig-nificantly smaller than that of the interobserver (P<0. 001),with a 0. 12° difference value of the pooled experimental standard deviation. Conclusion: When one observer measures a number of digital models, both the functional and the anatomic occlusal planes are suitable as a conference plane with equal repeatability. When several observers measure a large number of digital models,the functional occlusal plane is more reproducible than the anatomic occlusal plane,but the difference is small.

Resting pressure of the tongue body on the tongue anchorage pad / 北京大学学报(医学版)

Objective:To measure the resting pressure of the tongue body on the sagittal and vertical dimensions of the tongue anchorage pad ( TAP) , and to investigate the proper position of TAP as an an-chorage. Methods:Nineteen volunteers with individual normal occlusion (4 males and 15 females, age 23-33 years) were recruited in the study. Individualized TAP was designed and made for each subject. On the sagittal dimension, the pressure along the midline at the level of the distal of the second premolar (PM2), the first molar (M1) and the second molar (M2) were measured. On the vertical dimension, pressures on TAPs with height of -3 mm, 0 mm, and 3 mm were measured, with 0 mm standing for the reference point recorded by the tongue position record. The tongue resting pressure of the volunteers in the upright position was measured by miniature sensors ( FSS1500NS, Honeywell, USA) embedded in TAP. Nonparametric analysis was applied with the significant level of 0. 05. Results:On the vertical di-mension, the pressure obtained at the height of -3 mm, 0 mm, and 3 mm were 105. 83 Pa, 167. 75 Pa, and 254. 25 Pa, respectively (P<0. 001). On the sagittal dimension, the pressure detected at the level of PM2, M1, and M2 were 177. 64 Pa, 126. 72 Pa, and 109. 37 Pa, respectively (P<0. 001). Con-clusion:Tongue pressure rises significantly with the increase of TAP height. On the sagittal dimension, pressure decreases along the palatal midline in an anteroposterior direction. But in the clinical practice, we should also put comfort into consideration.

How to prevent the complications caused by the changes of pelvic anatomical relationship after gynecological surgery?

Gynecological surgery may bring about a series of corresponding diseases, because the excision of certain organs will have changed the pelvic anatomical relationship. The gynecologist must be well aware of the surgical indications for various diseases and select the proper method, range, and approach to achieve the optimal therapeutic effects with minimal injuries. This paper discusses some diseases caused by changes of pelvic anatomical relationship after gynecological surgeries, as well as their prevention and treatment.

Status quo and prevention of overtreatment in cervical diseases.

The objective of this paper was to review the diagnosis and treatment of cervical diseases. Often, due to improper judgment of interventional indications for cervical lesions, overtreatment to various degrees takes place, influencing patients' health and lives. This review analyzes the expression, causes and negative aspects of overtreatment of cervical lesions, and discusses the available therapeutic methods for cervical lesions, to remind gynecologists to master the interventional indications for proper treatment and avoid overtreatment, so as to achieve normalization and individualization in treating gynecologic diseases.

Confusing anchorage / 华西口腔医学杂志

Just like other subjects in medicine, orthodontics also uses some vague concepts to describe what are difficult to measure quantitatively. Anchorage control is one of them. With the development of evidence-based medicine, orthodontists pay more and more attention to the accuracy of the clinical evidence. The empirical description of anchorage control is showing inadequacy in modern orthodontics. This essay, based on author's recent series of studies on anchorage control, points out the inaccuracy of maximum anchorage concept, commonly neglected points in quantitative measurement of anchorage loss and the solutions. It also discusses the limitation of maximum anchorage control.

Efficacy of plasma exchange in the treatment of patients with fulminaut hepatitis / 中国基层医药

Objective To investigate the efficacy of plasma exchange in treating chronic fulminaut hepatitis.Methods 226 patients with fulminaut hepatitis were treated by plasma exchange at the base of conventional treatment and their consequence were compared with other 83 patients who did not receive the PE.Results The levels of the ALB,CHO and PTA in treatment group were higher than the control group,while the levels of ALT,AST,TB,CHE,TNF-α and ET in treatment group were lower than the control group.Conclusion The plasma exchange is an effective treatment for the patients with fulminaut hepatitis.

Local radioimmunotherapy of breast cancer-bearing nude mice using anti-CEA monoclonal antibody C50 labeled with ~(131)I / 吉林大学学报(医学版)

Objective To investigate and evaluate the curative effect of radioimmunological targeting drug on nude mice bearing breast cancer. Methods The anti-CEA monoclonal antibody C50 was combined with ~ 131 I to produce radioimmunological targeting drug. 16 nude mice inoculated subcutaneously with breast cancer cell MCF-7 with tumor diameter about 0.5 cm were randomly into 4 groups(n=4): group Ⅰ, injected in part with ~ 131 I-C50 18.5 MBq; group Ⅱ, injected in part with ~ 131 I-C50 3.7 MBq; group Ⅲ, injected in part with ~ 131 I-mIgG 18.5 MBq; group Ⅳ, injected in part with C50 0.75 ?g. The size of tumor volume and inhibitory rate (IR) after treatment for six weeks were calculated and compared with the control group. Results The tumor volume and curves for tumor growth and tumor weight had significant differences between group Ⅰ and the group Ⅲ as well as group Ⅱ (P0.05). Conclusion Anti-CEA monoclonal antibody C50 labeled with radionuclide ~ 131 I could inhibit the growth of the tumor when given locally. ~ 131 I-C50 has a potential value of clinical application

Comparative study on ordinary coordinates and standardized coordinates converted by general procrusts analyzation method in cluster analysis and discrimination analysis of AngleⅠ malocclusion / 北京大学学报(医学版)

Objective: To classify the AngleⅠ malocclusion subgroups using lateral radiographic films according to their ordinary coordinates and standardized coordinates converted by general procrusts analysis (GPA), and to compare the two kinds of classifications and their valne in diagnosis of malocclusion. Methods: 946 pretreatment lateral radiographic films of patients with Angle'I malocclusion were chosen and their ordinary coordinates were acquired via soft ware. The ordinary coordinates were then converted into standardized coordinates by GPA. All of the films were classified by cluster analysis and discrimination analysis applying the upper two kinds of coordinates respectively. Results: (1) Twenty one subgroups were identified according to the ordinary coordinates of the chosen films with the total differentiate rate of 92.7% and leave-one-out differentiate rate of 68.4% (Classification A). Correspondingly, 20 subgroups were identified according to the standardized coordinates with the two differentiate rates of 87.8% and 71.9% (Classification B). (2) If the ordinary coordinates were discriminated by Classification B, the total differentiate rate and leave-one-out differentiate rate were 79.8% and 60.2 % respectively. If the standardized coordinates were discriminated by Classification A, the two differentiate rates were 79.8% and 60.2 % respectively. (3) There were some subgroups having the similar form in Classification A and their difference mainly arose from the difference of the patient age, while there were no such subgroups like that in Classification B. (4)The proportion of the largest subgroup in total subjects is 15.9% and there were 8 subgroups having the number of subjects over 40 in Classification A, whilethe corresponding proportion and number of subgroups were 74.7% and 2 in Classification B.(5)Classification A and Classification B were both suitable to classify a new subject, but Classification B was required to standalize all of the subjects onc again, which was very complex, while Classification A was more simplified. Conclusion: Classification A and Classification B are interelated. GPA could concentrate the subjects in cluster analysis, which reduces some influence of the age to the classification, but the process to classify a new subject is very complex. Thus if quick diagnosis is needed in clinics, Classification A should be recommended, but the influence of the age should be noted.

Validity of tooth volume determinations using cone beam computed tomography / 北京大学学报(医学版)

Objective:To determine the accuracy of volumetric analysis of teeth in vivo using cone beam computed tomography(CBCT).Methods: The physical volume(Vw) of 24 bicuspids extracted for orthodontic purposes(16 were imaged with the i-CAT and 8 with the CB MercuRay before extraction) was determined using water displacement technique.Corresponding pre-treatment CBCT image data were uploaded into Amira 4.0 for segmentation and radiographic volume(Va).All measurements were performed twice by two observers.The statistical difference between Vw and Va was assessed using a paired t-test.The intra-and inter-observer reliability was determined by calculating Pearson correlation coefficients and intraclass correlation coefficients(ICC).Results: The overall mean Vw of teeth specimens was 0.553?0.082 cm3,while the mean Va was 0.548?0.079 cm3,0.529?0.078 cm3 for observer 1,and 0.567?0.085 cm3 for observer 2.There were statistically significant differences between Va and Vw(P

Craniofacial characters for Angle's class Ⅱ malocclusion using Procrusts superimposition and multivariate statistics / 北京大学学报(医学版)

Objective:Cluster and discriminant analysis of the morphological characters of Angle's Class Ⅱ malocclusion was performed using Procrusts standardization.The classification of craniofacial morphology with the help of morphometry and multivariate statistics was also discussed.Methods: A total of 894 class Ⅱ patients were collected from the orthodontic department,Peking University School and Hospital of Stomatology during 1997-2000.Using Procrusts standardization and cluster analysis,the samples were divided into different groups,discrimination equations were then established.Results: The samples were divided into 11 subdivisions by Procrusts superimposition and cluster analysis.Three discrimination equations were established.The accuracy rate of cross-validated grouped cases was 80.17%.Conclusion: Procrusts standardization had certain advantages in morphological classification;cluster analysis could be used in classification of Angle class Ⅱ malocclusion;For different types,the differentiate rate was not the same;the discrimination equations was the foundation for future research.

History and development of Chinese Orthodontics / 北京大学学报(医学版)

Orthodontics in China has experienced two important stages. At its early stage from 1950 s to 1970 s orthodontics was a division of prosthodontic department in China. There were 3 top professors in this field, who got partly training at one time or another in USA and returned to China working in Beijing Medical College, the Fourth Military Medical University and Shanghai Second Medical College. Among them, Professor Mao of Beijing Medical College was regarded as the father of Chinese Orthodontics. Removable appliance was the main tool at that stage and Prof.Mao brought forward Mao’s Classification of Malocclusion which is still used in China. The rapid developing stage began in the 1980 s when China opened its door to the world. More and more orthodontists got further training abroad and brought back advanced techniques since then. Up to now, we have already had more than one thousand of orthodontic specialists and established its own organization——the Chinese Orthodontic Society (COS), which holds domestic orthodontic meetings and organize its members to attend international meetings. Right now, almost all advanced techniques in diagnosis and treatment are adopted in China, including 3D imaging, self-ligating bracket appliance, and implant anchorage. Chinese orthodontists have started to present or publish papers in international meetings and journals and more than tiat, started to develop new app-liances, such as Driving-Force Straight Wire Appliance, which has shown advantages in treating skeletal Class Ⅲ malocclusion.

Cast analysis of 37 patients treated with MBT~(TM) appliance / 北京大学学报(医学版)

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.

Preliminary study of treatment mechanism and stability in deep overbite malocclusion with hyperdivergent and hypodivergent skeletal pattern / 北京大学学报(医学版)

40? or 40?)comprised 10 cases and the hypodivergent group (MP-SN

Cephalometric comparison of hard-tissue morphology between extraction and non-extraction orthodontic treatment in borderline cases / 北京大学学报(医学版)

Objective:To compare hard tissue morphology by cephalometric measurements between extraction and non extraction orthodontic treatment in borderline cases. Methods: The samples consisted of 33 cases selected as borderline cases by 5 orthodontic specialists. They were divided into 21 extraction cases (including 13 four first premolar extraction cases and 8 second premolar extraction cases) and 12 nonextraction cases by checking patients’ treatment records. Conventional cephalometric analysis was made to compare hard tissue structures before and after orthodontic treatment and the same comparison was made between two different extraction patterns. Results: No statistical difference was found on pretreatment hard tissue morphology between extraction and non extraction groups divided from borderline cases. The SNB angle of the four first premolars extraction group was smaller than that of the four second premolars extraction group by (4.0?1.3)?( P