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In April 2022,an epidemic occurred in Gongshu District,Hangzhou,where Zhejiang Cancer Hospital is loca-ted.And the hospital was confronted with the most extensive,the most unusual and the most urgent public health emergency crisis since its establishment.Taking patients as the core and proceeding from the public perspective,an authoritative voice of a hospital was conveyed in a timely and accurate manner,which demonstrated the hospital's resolution and executive power in the crisis.Based on Malcolm Gladwell's"tipping point"theory,the paper reveals the situation of online public opinion caused by the sudden epidemic and its response,discusses the hospital's communication practices in handling public health emergencies and provides hospitals with practical reference for brand promotion and operation.
ABSTRACT
There are many kinds of orthodontic movements that make the clinical schedule a genuine test. With the appearance of the skeletal anchorage, it became more straightforward to take care of numerous issues, like anchorage, tipping, interruption among others. The reason for this article was to survey outright anchorage, including signs, implantation site, and any kind of orthodontic element
ABSTRACT
To use a visualized method,tipping-point analysis to address missing data in clinical study and discuss related problems.All the possible outcomes caused by missing data were listed and the tipping points where P-values of hypothesis test changed at 0.05 significant level were found out,then the ratio of P＜0.05 was calculated,reflecting the reliability of the study's result.Tipping-point analysis can be applied to both continuous and binary data to help find points where p-values are changed.The area of P＜0.05 of continuous data is 93.6％,indicating that the reliability of success of the study is large;and the area of P＜0.05 of binary data is 29.7％,reflecting that the reliability of success of the study is small.Tipping-point analysis,which provides a visualized evidence for decision making,is suitable for analyzing clinical studies with missing data.
ABSTRACT
To use a visualized method,tipping-point analysis to address missing data in clinical study and discuss related problems.All the possible outcomes caused by missing data were listed and the tipping points where P-values of hypothesis test changed at 0.05 significant level were found out,then the ratio of P＜0.05 was calculated,reflecting the reliability of the study's result.Tipping-point analysis can be applied to both continuous and binary data to help find points where p-values are changed.The area of P＜0.05 of continuous data is 93.6％,indicating that the reliability of success of the study is large;and the area of P＜0.05 of binary data is 29.7％,reflecting that the reliability of success of the study is small.Tipping-point analysis,which provides a visualized evidence for decision making,is suitable for analyzing clinical studies with missing data.
ABSTRACT
OBJECTIVE: The aim of this study was to investigate whether labial tooth inclination and alveolar bone loss affect the moment per unit of force (M(t)/F) in controlled tipping and consequent stresses on the periodontal ligament (PDL). METHODS: Three-dimensional models (n = 20) of maxillary central incisors were created with different labial inclinations (5°, 10°, 15°, and 20°) and different amounts of alveolar bone loss (0, 2, 4, and 6 mm). The M(t)/F necessary for controlled tipping (M(t)/F(cont)) and the principal stresses on the PDL were calculated for each model separately in a finite element analysis. RESULTS: As labial inclination increased, M(t)/F(cont) and the length of the moment arm decreased. In contrast, increased alveolar bone loss caused increases in M(t)/F(cont) and the length of the moment arm. When M(t)/F was near M(t)/F(cont), increases in M(t)/F caused compressive stresses to move from a predominantly labial apical region to a palatal apical position, and tensile stresses in the labial area moved from a cervical position to a mid-root position. Although controlled tipping was applied to the incisors, increases in alveolar bone loss and labial tooth inclination caused increases in maximum compressive and tensile stresses at the root apices. CONCLUSIONS: Increases in alveolar bone loss and labial tooth inclination caused increases in stresses that might cause root resorption at the root apex, despite the application of controlled tipping to the incisors.
Subject(s)
Alveolar Bone Loss , Arm , Finite Element Analysis , Incisor , Periodontal Ligament , Root Resorption , ToothABSTRACT
OBJECTIVE: The aim of this laboratory study is to evaluate the influence of the shape and the length limitation of superelastic nickel-titanium (NiTi) archwires on lower incisors inclination during alignment and leveling. METHODS: Metal teeth mounted on a typodont articulator device were used to simulate a malocclusion of the mandibular arch (-3.5 mm model discrepancy). Three different shapes (Standard, Accuform and Ideal) of superelastic NiTi archwires (Sentalloy, GAC, USA) were tested. Specimens were divided in two groups: Group I, with no limitation of the archwire length; and Group II, with distal limitation. Each group had thirty specimens divided into three subgroups differentiated by the archwire shape. All groups used round wires with diameters of 0.014-in, 0.016-in, 0.018-in and 0.020-in. The recording of all intervals was accomplished using standardized digital photographs with orthogonal norm in relation to median sagittal plane. The buccolingual inclination of the incisor was registered using photographs and software CorelDraw. RESULTS: The results were obtained using ANOVA and Tukey's test at a significant level of 5%. The inclination of the lower incisor increased in both groups and subgroups. The shape of the archwire had statistically significant influence only in Group I - Standard (11.76º), Ideal (5.88º) and Accuform (1.93º). Analyzing the influence of the length limitation, despite the mean incisor tipping in Group II (3.91º) had been smaller than Group I (6.52º), no statistically significant difference was found, except for Standard, 3.89º with limitation and 11.76º without limitation. The greatest incisor tipping occurred with the 0.014-in archwires.
ABSTRACT
In many cases of orthodontic treatment the upper anterior teeth are retracted. Periodontal problems may arise during incisor retraction, if the amount of tooth movement and the amount of remodeling in the anterior cortical bone are not the same. Therefore in this study, to find out the relationship between the amount of tooth movement and the amount of bone remodeling during retraction of the upper anterior teeth, lateral cephalograms of 56 female patients over 18-year-old were taken before and after treatment. Among the 56 patients, two groups were divided according to the type of root movement during retraction. 26 patients mainly moved by tipping and 30 by bodily movement. The cephalograms taken before and after treatment were superimposed upon the true horizontal plane. In the Tip-Group, the horizontal bone remodeling/tooth movement ratio was 1 : 1.63, and in the Torque-Group it was 1 : 1.66. Because the amount of tooth movement and the amount of bone remodeling were not the same in both groups, in the Tip-Group the root apex moved away from the palatal cortical plate and closer to the labial cortical plate, whereas in the Torque-Group the root moved away from the labial cortical plate and closer to the palatal cortical plate. Therefore, there are limitations in the amount of incisor retraction in patients with a very thin anterior cortical plate in the maxilla, and in patients with severe skeletal discrepancies orthognathic surgery should be considered and when orthodontic camouflage treatment is the only possible method, the orthodontist must be aware of the limitations of treatment.
Subject(s)
Adolescent , Female , Humans , Bone Remodeling , Incisor , Maxilla , Orthognathic Surgery , Tooth Movement Techniques , ToothABSTRACT
Horseshoe Expander is one of Slow Maxillary Expansion(SME) which aims to accommodate the contra-lateral expansion and midpalatal suture expansion of the palate. The appliance consists of skeleton type screw embedded in split Horseshoe appliance. It is the objectives of the presentation to manifest the changes in dental & craniofacial components subsequent to the application of Horseshoe Expander. The subjects for this study consisted of 32 patients (mean age: 12.7). Frontal, lateral cephalometric headfilm were taken and study casts were fabricated before and after expansion. 24 items were measured, compared preexpansion with postexpansion. Especially, palatal volume was measured by means of "Hydro-measurement method". Tooth axis measurement on the dental casts were made with Universal bevel protractor, and Horseshoe Expander group were compared with RME group. This study of changes to maxillary expansion with Horseshoe Expander revealed the following significant results. 1. Triangular-shaped expansion pattern appeared in frontal cephalometric headfilm. 2. Palatal plane, occlusal plane, mandibular plane and upper incisor to FH increased in lateral cephalometric headfilm. 3. Palatal volume increased significantly. A slight bite opening, reduction of occlusal contact points showed in dental casts. 4. A 2.2:1 ratio of the amount of intermolar width in maxilla(orthodontic movement) to maxillary width (orthopedic movement) was determined. 5. Horseshoe Expander group has less buccal tipping tendency than RME group, by taking high correlation coefficients in the upper second premolar and first molar. It was suggested that Horseshoe Expander showed less orthodontic changes, less buccal tipping tendency. In addition, it was effective in maxillary expansion.
Subject(s)
Humans , Axis, Cervical Vertebra , Bicuspid , Dental Occlusion , Incisor , Molar , Palatal Expansion Technique , Palate , Skeleton , Sutures , ToothABSTRACT
The aim of this study were to measure and compare the stress level on three type brackets and each other material (stainless steel, ceramic) with tipping and torquing forces by using the finite element analysis and to design bioniechanically favorable brackets. For this study, three kinds of brackets were selected(A:Transcend-RMO, B:Signature-Unitek, C:PAW plain archwire appliance-applied for a patent in Yonsei University). The slot size of bracket was 0.022inch and the size of archwire was 0.0175x0.025inch and taper shaped archwire was used in PAW. Loading force in tipping was 4.27N and torquing force was 32.858N applied by archwire torsion with 19.7degree and 113 degree in C type bracket. The conclusions were that (1) The finite element method proved to be a useful tool in the stress analysis of orthodontic bracket subjected to various forces. (2) With tipping, the stresses were concentrated at the gingival wall of the wire slot where it meets the mesial bracket surface and the incisal wall of the wire slot where it meets the distal bracket surface and with torquing, the stresses were concentrated at the junction of the gingival or incisal wall and base of the slot. (3) The maximum stress value was higher in torquing force than tipping force and therefore it is desirable to design on the basis of torquing force. (4) It was considered that the change in material might be affect on the diminish of stress value in the place of stess concentration. (5) The maximum stress value was highest on PAW bracket when the tipping and torquing force was applied and therefore it would be desirable to use mechanically favorable material on PAW bracket.