BACKGROUND: It is very important to explore an optimal loading force that can both allow effective intrusion and cause no damage to the teeth.OBJECTIVE: To investigate the optimal loading conditions, including loading force values and directions, in the intruding mechanics of maxillary anterior teeth.METHODS: A three-dimensional finite element model (3D FEM) of the maxillary anterior teeth was constructed to include the periodontal ligament (PDL), alveolar bone, and appliance (brackets and wire). The initial stress distribution and force of the maxillary anterior teeth were analyzed when the 3D FEM was loaded with different intruding force values and directions. RESULTS AND CONCLUSION: The optimal value of the intruding force for 6 anterior teeth fell within the range from 0.5 N to 1.0 N. The maximum stress was detected at the distal cervical level of the lateral incisor, and a relatively even distribution of initial stress was observed at 20° palatal deviation to the Y axis. The results suggest that using mini-screw implants at the labial region between the canine and lateral incisor and a combined 0.5-1.0 N intruding force with a distal force could be an optimal intrusion force system by which patients with normal occlusion could obtain a pure intrusion of anterior teeth.

Objectives To study the changes of hard tissue before and after orthodontic treatment for Angle's class Ⅲ malocclusion adolescence patient with maxillary front traction. Methods 20 cases of Angle's class Ⅲ malocclusion adolescence patients were treated by front traction in maxilla, while there were 20 cases of Angle's class Ⅰ malocclusion adolescence patients as the control group. Cephalometric a-nalysis was carried out before and after the treatment. Data were analyzed by SPSS11.0 system using paired t-test. Results There were significant increases in the length, anteroposterior diameter and thick-ness of maxillary sinus (P<0.05), while there was no significant differences in the site and central point of maxillary sinus(P>0.05). Conclusions It is a effective approach to change the hard tissue after ortho-dontic treatment for Angle's class Ⅲ malocclusion adolescence patient with front traction in maxillary area.

[Objectives]This study was designed to evaluate the treatment effects of a new movable molardistalization appliance for distal movement of maxillary first molars on Angle's Class Ⅲ malocclusion adolescence patients with the second premolar crowded.[Methods]Sixteen patients were treated by a new movable molardistalization appliance.Cephalometric analysis and model measurement was carried out before and after the treatment.Data were analyzed by paired t-test.[Results]The molars were distalized 5 mm during an average time of 3.8 months.There were significant increases in the Angle SNA and A-NPg(P ＜0.05).[Conclusion]it was a effective way to get space and improve patient's profiles on Angle's Class Ⅲ malocclusion adolescence patients with the second premolar crowded by the new movable molardistalization appliance.It was also conducive to patient's oral hygiene.

Acute Disease ; Adolescent ; Adult ; Bridged-Ring Compounds ; poisoning ; Cardiomyopathies ; etiology ; therapy ; Creatine Kinase ; blood ; Creatine Kinase, MB Form ; Electrocardiography ; Foodborne Diseases ; blood ; complications ; therapy ; Glutamyl Aminopeptidase ; blood ; Humans ; Isoenzymes ; blood ; Male ; Middle Aged ; Nausea ; etiology ; Seizures ; etiology ; Treatment Outcome

BACKGROUND:Distraction osteogenesis applied in patient’s canine distal movement, can greatly improve the speed of tooth movement, and protect the molar anchorage. But the researches on the traction rate, canine pulp vitality, canine periodontal tissue remodeling and the biological mechanisms of the technology are rare recently. OBJECTIVE:To evaluate the feasibility of rapid canine retraction through distraction osteogenesis of the periodontal ligament in adult patients and to monitor the pulp vitality, root resorption and periodontal remodeling of the canine. METHODS:Nine malocclusion patients were selected, and the bilateral maxil ary canine in adult patients were rapidly retracted and moved to the scheduled position using modified distraction devices. The canine distal movement distance, anchorage loss, root resorption and alveolar interval alterations were measured through intraoral radiographs, and lateral cephalograms. The pulp and periodontal of canine were mointrored. RESULTS AND CONCLUSION:The canines could be rapidly retracted to the schedualed position through distraction osteogenesis of the periodontal ligament in 12-16 days, the average amount of retraction was 7.18 mm and the canines tipped distal y (13.24±2.87)°. The anchorage loss was 0.5 mm. There was no obvious root resorption and periodontal tissue loss. The pulp vitality of the canines was decreased significantly right after distraction, but it recovered significantly after 3 months. The results indicated that periodontal ligament distraction osteogenesis can significantly accelerate canine movement speed, shorten treatment time, while protecting the molar anchorage;there was no significant adverse reaction of root resorption, loose teeth, pulp necrosis and loss of periodontal tissue. Indcating that distraction osteogenesis of periodontal ligament can move canines rapidly and effectively.

Objective :To explore influence of intra—arterial thrombolysis combined hyperbaric oxygen on serum levels of soluble intercellular adhesion molecule—1 (sICAM—1) and calcitonin gene related peptide (CGRP) in patients with severe ischemic stroke .Methods : A total of 96 patients with severe ischemic stroke in our hospital were randomly and equally divided into thrombolysis group and combined treatment group (received intra—arterial thrombolysis +hyperbaric oxygen therapy ).United States National Institutes of Health Stroke score (NIHSS) was used to assess neurological function recovery , and modified Rankin rating score (mRS) was used to assess recovery of clinical symptoms.After two—week treatment ,clinical therapeutic effect etc .were compared between two groups .Results :Compared with thrombolysis group after treatment ,there was significant rise in total effective rate (77.08% vs. 93. 75%, P＝0.021) ;significant reductions in scores of NIHSS [ (8.10 ± 3.45) scores vs .(5.36 ± 2.11) scores] and mRS [ (2.58 ± 0. 80) scores vs .(1.81 ± 0.76) scores] ;significant reduction in serum sICAM—1 level [ (237.31 ± 18. 04) ng／ml vs.(220.25 ± 16.40) ng／ml] ,and significant rise in serum CGRP level [ (27.02 ± 6.06) pg／ml vs. (35.24 ± 6.13) pg／ml] in combined treatment group , P＝0.001 all.There was no significant difference in revascu—larization within two weeks between two groups , P＝0.551. Conclusion : Intra—arterial thrombolysis combined hy—perbaric oxygen possesses significant therapeutic effect on patients with severe ischemic stroke .It can relieve clinical symptoms ,recover cognitive function ,improve revascularization rate in these patients .

BACKGROUNDBone morphogenetic protein (BMP)-2, alkaline phosphatase (ALP), and collagen type I are known to play a critical role in the process of bone remodeling. However, the relationship between mechanical strain and the expression of BMP-2, ALP, and COL-I in osteoblasts was still unknown. The purpose of this study was to investigate the effects of different magnitudes of mechanical strain on osteoblast morphology and on the expression of BMP-2, ALP, and COL-I.

METHODSOsteoblast-like cells were flexed at four deformation rates (0, 6%, 12%, and 18% elongation). The expression of BMP-2 mRNA, ALP, and COL-I in osteoblast-like cells were determined by real-time quantitative reverse transcription polymerase chain reaction, respectively. The results were subjected to analysis of variance (ANOVA) using SPSS 13.0 statistical software.

RESULTSThe cells changed to fusiform and grew in the direction of the applied strain after the mechanical strain was loaded. Expression level of the BMP-2, ALP, and COL-I increased magnitude-dependently with mechanical loading in the experimental groups, and the 12% elongation group had the highest expression (P < 0.05).

CONCLUSIONMechanical strain can induce morphological change and a magnitude-dependent increase in the expression of BMP-2, ALP, and COL-I mRNA in osteoblast-like cells, which might influence bone remodeling in orthodontic treatment.

Alkaline Phosphatase ; metabolism ; Analysis of Variance ; Animals ; Bone Morphogenetic Protein 2 ; metabolism ; Cell Line ; Collagen ; metabolism ; Collagen Type I ; metabolism ; Mice ; Osteoblasts ; cytology ; metabolism

Purpose: This study evaluated the distance from the posterior root apices to the maxillary sinus floor (MSF) and the frequency of roots touching or protruding through the MSF using cone-beam computed tomography (CBCT). Materials and Methods: This study included 100 subjects divided into different vertical and anteroposterior skeletal growth patterns. On CBCT images, the distance from the posterior root apices to MSF was measured and the frequency of roots touching or protruding through the MSF was evaluated using NNT software (version 5.3.0.0; ImageWorks, Elmsford, NY, USA). Results: No statistically significant differences were found in the distance from the posterior root apices to the MSF among vertical skeletal groups (P>0.05). The palatal roots of the first molar and the palatal, mesio-buccal and disto-buccal roots of the second molars had significantly less distance from MSF in skeletal class II than in class III (P<0.05). The high-angle group had the highest frequencies of roots touching or protruding into the maxillary sinus (49.8%); the lowest proportion of these roots was found in skeletal class III (28.3%) and the highest proportion in class II (50.3%). Males had shorter distances from the posterior root apices to the MSF and higher frequencies of roots protruding through or touching the MSF than females. Conclusion Anteroposterior skeletal growth patterns and sex affected the distances from the maxillary posterior roots to the MSF. The frequency of roots protruding into or touching the sinus was affected by both vertical and anteroposterior skeletal groups and sex. These findings have implications for dental practice.

BACKGROUNDAnimal models are needed for the study of rapid tooth movement into the extraction socket through distraction osteogenesis of the periodontal ligament.

METHODSModified distraction devices were placed on eight dogs between the first and third mandibular premolars on the left sides; similar placement of traditional straight wise appliances on the right sides served as the control. The experimental distractors were activated (0.25 mm/d) twice a day and the control devices were activated (100 g) for two weeks with consolidation periods at weeks two, three, six, and ten. Two dogs were sacrificed at each consolidation time point; rates and patterns of tooth movement, loss of anchorage, and periapical films were evaluated, and the affected premolars and surrounding periodontal tissues were decalcified and examined histologically. General observations, X-ray periapical filming and histology examination were performed.

RESULTSDistal movement ((3.66+/-0.14) mm) measured two weeks after modified distraction exceeded that achieved using the traditional device ((1.15+/-0.21) mm; P<0.05). Loss of anchorage was minimally averaged (0.34+/-0.06) mm and (0.32+/-0.07) mm in the experimental and control sides, respectively. By radiography, apical and lateral surface root resorptions on both sides were minimal. Alveolar bone lesions were never evident. Fibroblasts were enriched in periodontal ligaments and bone spicules formed actively along directions of distraction.

CONCLUSIONSThe canine model is suitable for the study of rapid tooth movement through distraction osteogenesis of the periodontal ligament. The technique accelerates tooth movement, periodontal remodeling, alveolar bone absorption, and may induce fibroblast formation, as compared to the traditional orthodontic method, without adversely affecting root absorption, bone loss, tooth mobility and anchorage loss.

Animals ; Dogs ; Male ; Osteogenesis, Distraction ; methods ; Periodontal Ligament ; physiology ; surgery ; Root Resorption ; etiology ; Tooth Movement Techniques ; methods

OBJECTIVETo inhibit the expression of beta-catenin and investigate the effect of the beta-catenin gene on Jurkat and K562 cells.

METHODSsiRNA specifically knocking down the expression of beta-catenin was used to testify the function of beta-catenin in Jurkat and K562 cells. Real time polymerase chain reaction and Western blot were performed respectively to testify the mRNA level and protein level of beta-catenin. Growth curve was determined by counting viable cells using trypan blue refusal-dyed method. The proliferation of cells was assayed by clonogenic counting and MTT method. The apoptotic cells were measured by Annexin V/PI staining. The cell cycle analysis was performed based on propidium iodide staining.

RESULTSCompared with the control group (transfected with siRNA directed against scramble gene), the survival, colonogenicity, and proliferation of the Jurkat and K562 cells were significantly decreased in experimental group transfected with beta-catenin siRNA. The colonogenicity was decreased from 31.9 +/- 5.55 (siRNA) to 25.0 +/- 5.13 (control) in Jurkat cells, and from 47.33 +/- 8.52 (siRNA) to 39.33 +/- 6.26 (control) in K562 cells (both P <0.05). The inhibition rate was (49.3 +/- 9.86)% (siRNA) and (15.1 +/- 6.55)% (control) respectively in Jurkat cells, and (39.4 +/- 7.56)% (siRNA) and (10.1 +/- 6.89)% (control) in K562 cells (both P <0.05). In addition, the apoptotic rate increased from (23.5 +/- 2.82)% (control group) to (55.9 +/- 2.22)% (experiment group) in Jurkat cells and from (14.9 +/- 8.54)% (control group) to (27.9 +/- 15.3)% (experiment group) in K562 cells. However, cell cycle analysis revealed no obvious phases change both in Jurkat and in K562 cells.

CONCLUSIONKnock-down of beta-catenin gene may decrease the proliferation, survival, and clonogenicity in Jurkat cells and K562 cells.

Apoptosis ; genetics ; physiology ; Blotting, Western ; Cell Cycle ; genetics ; physiology ; Cell Line ; Cell Proliferation ; Humans ; Jurkat Cells ; cytology ; metabolism ; K562 Cells ; cytology ; metabolism ; RNA, Small Interfering ; genetics ; physiology ; Reverse Transcriptase Polymerase Chain Reaction ; beta Catenin ; genetics ; metabolism ; physiology