OBJECTIVEThis study aims to construct a three-dimensional finite element model of a maxillary anterior teeth retraction force system in light wire technique and to investigate the difference of hydrostatic pressure and initial displacement of upper anterior teeth under different torque values of tip back bend.

METHODSA geometric three-dimensional model of the maxillary bone, including all the upper teeth, was achieved via CT scan. To construct the force model system, lingual brackets and wire were constructed by using the Solidworks. Brackets software, and wire were assembled to the teeth. ANASYS was used to calculate the hydrostatic pressure and the initial displacement of maxillary anterior teeth under different tip-back bend moments of 15, 30, 45, 60, and 75 Nmm when the class II elastic force was 0.556 N.

RESULTSHydrostatic pressure was concentrated in the root apices and cervical margin of upper anterior teeth. Distal tipping and relative intrusive displacement were observed. The hydrostatic pressure and initial displacement of upper canine were greater than in the central and lateral incisors. This hydrostatic pressure and initial intrusive displacement increased with an increase in tip-back bend moment.

CONCLUSIONLingual retraction force system of maxillary anterior teeth in light wire technique can be applied safely and controllably. The type and quantity of teeth movement can be controlled by the alteration of tip-back bend moment.

Finite Element Analysis ; Humans ; Incisor ; Maxilla ; Tooth Movement Techniques ; methods ; Tooth Root ; Torque

Objective To study the effects of CBL teaching mode on treatment plan making process among orthodontic postgraduates. Methods Totally 42 junior and senior orthodontic post-graduates were randomly divided into 2 groups (21 per group)named as experimental group and test group. Each group was further divided in to 3 teams involved in CBL and traditional teaching. Six cases of the same type malocclusion were selected each time;after 4 teaching cycle,test scores of two groups were analyzed with SPSS 19.0. Results were shown as mean ± standard deviation and t test andχ2 test were applied to evaluate the rationality and accuracy of treatment plan made by students. Survey questionnaire were issued to teachers and students after class and the assessment results of CBL teaching mode were summed up. Results Test scores were (88.61±8.34)in experimental group and (76.13±8.59)in control group with significant differences (t=3.16,P=0.01). Pass rate of two groups were 96.12%and 87.51%with significant differences (χ2=4.76,P=0.02). During the first teaching program, accurate rates of experimental group and control group were respectively 31.00% and 36.70% and ra-tionality were 33.31%and 33.30%. During the second teaching program,accurate rates of experimen-tal group and control group were 68.80%and 45.70%and rationality were 62.72%and 43.37%. During the third teaching program,accurate rates of experimental group and control group were 89.70% and 51.20%,and rationality were 95.00% and 66.70%. During the fourth program,accurate rates of ex-perimental group and control group were respectively 97.80% and 55.30% and rationality were 98.30% and 75.60%. Conclusions CBL teaching mode is helpful to improve the students' ability of analyzing clinical cases and making more accurate and rational treatment plan,however the increasing teaching cost and the course load are also involved.

BACKGROUND:Whether the functional mandibular deviation wil cause osteal mandibular deviation and whether the mandibular growth pattern wil change are stil controversial. Vascular endothelial growth factor can increase the endothelial permeability, stimulate endothelial cel mitosis and promote angiogenesis and regulate the formation of bone. OBJECTIVE:To investigate the effect of functional mandibular deviation on the expression levels of vascular endothelial growth factor in condylar cartilage in growing rats. METHODS:Sixty four-week-old male Sprague-Dawley rats were randomly divided into control group (n=20) and experimental group (n=40). Each animal in experimental group received a nichrome appliance which was designed by our team. Lower mandible suffered from left functional deviation (2.1±0.3) mm to simulate functional mandibular asymmetry. RESULTS AND CONCLUSION:The number of vascular endothelial growth factor-positive cels in the sagittal posterior deviation region of rats with functional mandibular deviation was less than that in the non-deviation region at 7-28 days after model establishment. The number of vascular endothelial growth factor-positive cels was less in the sagittal central and coronal central deviation region than in the non-deviation region in rats with functional mandibular deviation at 14-28 days after model establishment, but was close to the control group. The number of vascular endothelial growth factor-positive cels was less in the coronal lateral deviation region than in the non-deviation region and control group in rats with functional mandibular deviation at 14-28 days after model establishment. These results indicated that after the mandible functional lateral deviation in adolescent rats, the expression of vascular endothelial growth factor was different in bilateral condylar cartilage, caused the alterations in osteoblast activity in cartilage, and possibly affected the normal growth and development of rat mandible, suggesting that functional mandibular deviation should be corrected as early as possible.

Objective To evaluate the implementation effect of Malaria Elimination Project supported by the Global Fund in Shaanxi Province so as to provide the evidence for the scientific implementation of Malaria Elimination Action Plan and the exami-nation and evaluation work. Methods The data of malaria prevention and control work were collected and analyzed statistically in 27 counties from 2010 to 2012 in order to evaluate the measures and effects of malaria control. Results There were 64 reported cases in the project areas from 2010 to 2012,and the average annual incidence rate was 0.15/10 million with a declining trend. The infected area sources of patients were mainly imported overseas accounting for 79.69%of the total cases. The blood completion rate of febrile patients was 94.14%,and the scope of the blood smears testing work had expanded to 88 counties(including 61 third-class counties). The training coverage rate of malaria prevention knowledge and skills had achieved to 100%. The awareness rates of malaria prevention and control were 91.68%and 89.44%in the students and local residentsrespectively. The case reporting with-in 24 h after diagnosed,epidemiological case study and outbreak disposal,laboratory testing and confirming and the other case management capabilities had also improved significantly. Conclusions The implementation of the Global Fund Malaria Project in Shaanxi Province has accelerated the process of Malaria Elimination work and improved significantly the malaria control ability in the project areas.

Objective To investigate the possible mechanism of the gap junctional influence on the change in permeability of the blood-brain barrier(BBB)after reperfusion subsequent to cerebral ischemia.Methods In the test laser scanning confocal microscope(LSCM)was used to investigate the change of Cx43 levels and distribution.The MCAO/R model was induced using intraluminal suture technique first described by Longa with a little modification.A total of 60 Wistar rats were divided into 4 groups:the sham-operation group,control group,octanol-treatment group and DMSO vehicle control group. Control group were further divided into seven subgroups at different time points of reperfusion after middle cerebral artery occlusion.To observe the change in permeability of BBB,Evans blue(EB)in the brain tissue was surveyed by the means of EB fluorescent quantitation.Octanol-treatment group and DMSO vehicle control group were done at the point of the peak of permeability of BBB.Octanol,the specific blocker for gap junctions(GJ)was used in an intervention study.To compare the amount of EB with the same point of groups,the influence of octanol on BBB permeability was investigated.Results At 3 h of reperfusion after cerebral ischemia for 2 h,the permeability of BBB began to increase,reached the peak at 24 h of reperfusion and was still elevated at 72 h.The Cx43 expression formed into bigger plague and remained linear disposition in the penumbra after reperfusion subsequent to cerebral ischemia.Octanol group was done at 24 h of reperfusion after cerebral ischemia.The amount of EB of octanol group((4.924?0.296)?g/g)was significantly lower than that of corresponding operation control group(5.543?0.506)?g/g.Conclusions (1)Cx43 expression is concentrated around vessels in brain.The Cx43 forms into bigger plague and the function maybe strengthens after reperfusion.Gap junction might aggravate the disruption of BBB.(2) Octanol,the specific blocker of gap junctions,could effectively prevent the permeability of BBB from increasing and has a protective effect on BBB.

OBJECTIVETo study the influence of nasolabial angle alteration on facial profile attractiveness and investigate the perception differences in profile attractiveness among laypeople.

METHODSA young Chinese female with normal hard and soft tissue cephalometric values was chosen as a research object. Profile photograph was taken in a natural head position. Photoshop software was chosen to rotate the nose tip and upper lip, thus changing the degree and direction of nasolabial angle. A total of 33 different profile pictures were achieved. Thirty-three professional orthodontists and 64 non-professionals were chosen to score these 33 pictures.

RESULTSWhen the upper lip position was fixed, the profile was considerably attractive because the angle of nasal tip was not changed or altered. When the nasal tip rotation angle was fixed, profiles with a retroclined upper lip were considered significantly attractive by the layperson and professional groups. Regardless of the direction of the nasal tip rotation, the respondents considered the profile with a retroclined upper lip highly attractive.

CONCLUSIONThe soft tissue profile with a retroclined upper lip looks considerably attractive in Chinese female populations. Therefore, during an orthodontic treatment, appropriate retraction of the incisor is recommended to improve soft tissue profile attractiveness.

Cephalometry ; Esthetics ; Face ; anatomy & histology ; Female ; Humans ; Incisor ; Lip ; Nose

Objective To establish a HPLC/MS/MS method for the determinati on of gentiopicroside in human urine.Methods The urine sample was treated by solid-phase extraction with internal standard of caffeine;The RESCEK C8 colum n(150mm?2.1mm,5 ?m) was used as the analytical column with a mobilep hase consisting of methanol-10mmol? L-1 NH4AC buffer(pH=6.5)-acetonit rile(50∶40∶10,V/V),the flow rate was 0.2 mL? min-1;A triple quadruple tandem mass spectrometer was used as the detector,Electrospray ioniza tion source was applied and operated in positiveion mode.Gentiopicroside and caffeine were detected by monitoring the ion transition of m/z 374.1→ 195.2 and m/z 195.2→ 138.2 respectively.Results The linear range was 30～ 9000 ng?mL-1(r=0.9980) for gentiopicroside in human urine.The recovery was 91.10% ～ 9 6.21 %,The absolute recovery was 100.52% ～ 103.83%,The within-day and between-day precisions were less than 10 %.Conclusion The method is proved to be sensitive,accurate,rapid,specific.

Objective:To explore the methods to improve the professional core competencies of medical students in the standardized residency training.Methods:A total of 82 medical students who participated in the standardized residency training ("resident students" for short) in the same period were selected in this study, and the self-edited professional core competencies textbooks were used for regular theoretical study, and at the same time, clinical practice cases were collected for regular scenario reduction teaching. When the resident students entered the department and after 12 months of the standardized training, the professional core competencies training evaluation scale was used to evaluate and compare the scores of the resident students, and the value of the above-mentioned training model to improve the professional core competencies of the resident students was evaluated. SPSS 18.5 was performed for t test between groups. Results:After being trained by the above model, the selected students had significantly improved such competencies as communication, cooperation and problems solving ( P<0.05). Compared with the scores of resident students before and after the training, there was no significant difference in communication and cooperation with other students ( P>0.05), with low satisfactory communication with the leader ( P>0.05), but the problem-solving ability had been significantly improved ( P<0.05), while the score of which was low and it should be pay more attention to in the future training. Conclusion:In the process of standardized residency training, the application of the above-mentioned training model can significantly improve the professional core competencies of resident students, and at the same time, it's necessary to strengthen the cultivation of satisfactory communication with leaders and problem solving ability.

OBJECTIVEThis study aims to identify the effects of corticotomy-assisted orthodontic premolar intrusion andevaluate the changes of root resorption and the alveolar bone.

METHODSBoth sides of the mandible of eight male Beagle dogswere randomly assigned into experimental and control groups. The third (P3) and fourth (P4) premolars were intruded withboth mini-screw implant anchorage (MIA) and corticotomy on the experimental side. By contrast, P3 and P4 were intrudedwith MIA alone on the control side. During pre-operation and after 2, 4, 8, and 12 weeks of orthodontic force applications,cone beam computed tomography was performed on every dog. The distance of tooth intrusion and root resorption of furcation, as well as the apex and height changes of the alveolar bone were measured and analyzed.

RESULTSThe intrusion distanceof premolars on the experimental side was greater than that on the control side (P < 0.05). The root of furcation and apex onboth sides occurred in root resorption, and the root resorption of the apex on the experimental side was lighter than that onthe control side after 12 weeks of force application (P < 0.05). The alveolar bone height decreased, and the height reductiondistance on the experimental side was greater than that on the control side after 8 and 12 weeks of force application (P < 0.05).

CONCLUSIONCorticotomy accelerates orthodontic molarintrusion and reduces root resorption.

Animals ; Bicuspid ; anatomy & histology ; Bone Screws ; Cone-Beam Computed Tomography ; Dogs ; Male ; Mandible ; Root Resorption ; Tooth Movement Techniques ; Tooth Root

Objective To study the effects of case-based learning (CBL) teaching method combined with network on orthodontic postgraduate clinical ability training. Methods Totally 40 ortho-dontic postgraduates were randomly divided into 2 groups (20 per group) named as experimental group (EG) and control group(CG). EG involved in CBL combined with network teaching method,while CG with CBL method only. after 5 teaching cycles,test scores of two groups were analyzed with SPSS 22.0. Results Average scores were (86.60 ±9.71) in EG and (85.45 ±10.79) in CG ,without statistical differences (P=0.73). Pass rate of two groups were 95.00% and 90.00% ,without statistical differences (P=1.00); As for the questionnaire survey, most of the students (90.00%) in EG considered CBL com-bined with network teaching method had no confliction with the clinical time,and helped to carry out in-depth clinical topic discussion. What was more,all of them (100.00%) in EG believed network facilitate their learning. Only part of them (60.00%) in EG thought that they spent a lot of time on reference material preparation. Conclusions Both CBL combined with network teaching method and CBL method can improve the clinical ability of orthodontic postgraduates significantly. However, CBL combined with network teaching method has advantages over time management, knowledge learning and resource sharing.