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@#Understanding the etiology and mechanism of early malocclusion and the characteristics of craniofacial growth and development is a necessary prerequisite for scientific early treatment. Clarifying the basic principles of early orthodontic treatment is conducive to the coordinated development of the orognathic system.In order to improve the success rate of early treatment and reduce the difficulty of orthodontic sequential treatment in the future, it is necessary to identify indications of temporary malocclusion and early treatment with bad prognosis. This article starts from the basic concept, in order to provide guidance for clinical practice.
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Objective To study stress distributions of lower dentition distally moved with miniscrews in external oblique line area when the traction hooks with different lengths were placed at different positions by the three-dimensional (3D) finite element method. Methods Based on cone beam computed tomography (CBCT) data from a patient, traction hooks with the heights of 2 mm and 7 mm were constructed and fixed between the lateral incisors and the canine brackets, as well as between the canines and the first premolar brackets. Four kinds of 3D finite element models of full dentition distally moved with miniscrews were constructed. The 3 N traction force was loaded between the traction hook and the miniscrews. The maximum von Mises stress and initial displacement of the mandibular teeth and dentition under four working conditions were analyzed. ResultsWhen the traction hook with 7 mm-height was placed between the lateral incisor and the canine, the lower central incisor rotated clockwisely, with the crown moving labially and the root moving lingually. But under the other three working conditions, the central incisor rotated counterclockwisely, and the crown and root moved lingually. When the traction hook with 7 mm-height was placed between the canine and the first premolar, the lower canine crown moved proximally. But under the other three working conditions, both the crown and root moved distally. Under four working conditions, the mandibular molars all rotated counterclockwisely,with the crown and root moving distally. Conclusions Through 3D finite element analysis, biomechanical mechanism of the effect of different traction hooks on mandibular tooth movement during distalization of the lower dentition was elucidated.With full understanding of the biomechanical mechanism, proper selection for length and placement of the traction hook can achieve distal movement of the entire mandibular dentition more efficiently.
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Objective: To investigate the development rules of craniofacial development in patients with cleft lip and palate after surgical repair. Methods: 50 patients with repaired complete unilateral cleft lip and palate (UCLP) and 28 with complete unilateral cleft lip (UCL) were included. The subjects were divided into 3 groups according to their cervical vertebral maturation. Lateral cephalograms of all subjects were obtained. The data were analyzed and compared by PRISM 6. 0. Results: The values of face height (N-Me and ANSMe), mandibular size (Co-Go, Go-Gn, Co-Gn) of the patients in CS5 CS6 stage were bigger than those of the patients with the same type of cleft in CS1 and CS2 stage (P ＜ 0. 05) . The values of maxilla length and location showed no statistical difference between the development periods of the same type of cleft (P＞ 0. 05) . Conclusion: After surgical reair, with development, the maxilla of the UCLP/UCL patients may not change significantly. The mandible may grow significantly.
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In recent years, more and more female adult patients complained the aesthetic problems such as the decline of face fullness during the treatment. In the course of 2-3 years of orthodontic treatment, the age-related change of the facial bone structure in the adult is limited, and therefore, the shape change mainly depends on the change of the soft tissue. In this paper, the factors such as age-increasing factors, the structural factors of the face,the width of the arch and the change of the occlusal height were analyzed to explore the changes of facial soft tissue and related factors in the treatment with a view to providing a reference for clinical application.
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Objective: To investigate the clinical perspectives of 3dMD photography in orthodontics. Methods: 60 patients with skeletal Ⅰ malocclusion (30 males, 30 females, aged 18 to 35 years) were selected. Facial pictures of them were taken by 3dMD photography and traditional photography respectively, photographing time was recorded. Facial measurements' quality data were analyzed by SPSS 16. 0. Results: The photographing time of the 3dMD group and traditional photographic group was(14. 99 ± 1. 34) s and (45. 33 ± 7. 75) s respectively(P＜ 0. 05); there was no significant difference between the 2 groups in the quality scores. Conclusion: The clinical use of 3dMD in patients can save the operation time and can get similar by the use of results traditional radiography.
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Objective: To study the effects of long non-coding RNA linc-01135 on the osteogenic differentiation of inflammatory PDLSCs(P-PDLSCs) under 12％ static mechanical strain loading. Methods: Cells were isolated and cultured from the healthy and periodontitis samples respectively to obtain healthy PDLSCs(H-PDLSCs) and P-PDLSCs. RT-PCR were used to identify the expression level of linc-01135. Lentiviruses were used to upregulate and downregulate the expression of linc-01135, and the osteogenesis gene expression were analyzed by RT-PCR and the osteogenesis differentiation capability were evaluated by alizarin red staining. Results: linc-01135 expression in P-PDLSCs was lower than that in H-PDLSCs. When the expression of linc-01135 was upregulated in P-PDLSCs before 12％ SMS loading, the expression level of RUNX2, ALP, OPG was significantly increased. In contrast, the expression of RUNX2, ALP, OPG was significantly decreased when the expression of linc-01135 was suppressed. Alizarin red staining proved the same trend. Conclusion: linc-01135 can promote the osteogenic differentiation capability of P-PDLSCs under 12％SMS loading.
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Objective:To study 3-dimensional facial soft tissue reference values of Chinese Han nationality adults with normal occlusion and explore the facial morphology differences between men and women.Methods:3dMD images from 30 men and 32 women of Han nationality,aged 18-35 years,with normal occlusion were analyzed and compared between the men and women on 19 linear distances,8 angular measurements and 10 linear distance ratios.Results:Linear distances concerning the width and height of facial and organic contours were larger in men(P<0.05),while the ratio of facial height to width were larger in women(P<0.05);the nasofrontal angle and nasal prominence angle were both smaller(P<0.05) but nasofacial angle were larger(P<0.05) in men than in women.Conclusion:The facial and organic contours are larger in men than in women.Men have wide-elliptical face while women have thin-elliptical one.The nose of men is more prominent than women.
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Objective:To investigate the efficacy and safety of SIMI mouthguard paint(test group) in the treatment of enamel demineralization during orthodontic therapy with fixed applince.Methods:152 cases underwent orthodontic therapy with fixed applince were included in a randomized,open,positive control trial,and were treated by SIMI and Duraphant fluoride toothpast (control group) respectively(n =76).The enamel opaque spot was observed before and 3 months after using the products.The oral mucosa reactions,asthma attacks or stomach nausea and other adverse events were recorded.Results:150 cases (n =75) completed the trial.The results showed that the test group was non-inferior compared with the control group.No adverse event was found in both groups.Conclusion:SIMI mouthguard paint is effective in control of enamel demineralization during orthodontic therapy with fixed applince.
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Objective:To study the morphologic standard values of craniofacial hard-tissue of the youths in Xi'an.Methods:CBCT scanned cephalometric data of 100 selected volunteers (50 males and 50 females)with individual normal occlusion were collected.31 landmarks and 31 measurements were compared between sexes and between 3D and 2D data with software InvivoDental 5.2,WinCeph 8.0.and SPSS 19.0.Results:1.In the 3D measurements,vertical growth of mandible in the females was more than that in the males. The values of torque of lower incisor,basis length,height of rumi mandibulae and length of corpora mandibulae in the males were bigger than those in the females.2.Compared with 2D measurements,there existed statistically significant differences in most parameters except U1-NA(mm).Conclusion:3D analysis with CBCT may provide more accurite morphologic data for craniofacial hard tissues.
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This paper focuses on the diagnosis and treatment of upper impacted canines.Radiograph diagnosis is the most important tool in-cluding panoramic,CT and CBCT.Preventive and interceptive treatment,tooth extraction,self tooth transplantation and orthodontic traction can be used in the treatment.
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The paper is to explore the goals and models of Orthodontic teaching in eight-year medical students. It tries to design some teaching goals, teaching models and standards of examination to train medical students according to the eight-year program characteristics, and discuss the problems of eight-year program orthodontic teaching.
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Objective:To compare shear bond strength(SBS)of bonded and rebonded orthodontic brackets and influence of rebonded orthodontic brackets using different treatment methods on SBS.Methods:60 extracted premolars were evenly divided into three groups.Brackets were debonded with conventional techniques and then removed of residual adhesives from the base mesh using three different treatments.In groupⅠ,rebond a new bracket at the second,third bonding times.In group Ⅱ,remove residual adhesives from the base mesh with fire at the second,third times,then rebond the same bracket.In group Ⅲ,remove that using a tungsten carbide bur at the second,third times,then rebond the same bracket.Shear test was performed to compare the SBS and adhesive remnant indexes(ARI)among different groups.Results:The SBS of three groups at the first bonding sequence were(10.00?2.95)MPa,(9.57?2.45)MPa and(9.09?2.58)MPa.The SBS at the second,third debonding sequence in group I,group II,and group III were(9.55?2.84)MPa and(10.32?2.59)MPa,(7.30?2.15)MPa and(7.14?1.93)MPa,(12.13?2.93)MPa and(12.86?3.08)MPa,respectively.In group Ⅱ,the SBS was significantly lower,however,in group Ⅲ,the SBS was significantly higher,and the results showed significant differences(P
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Objective:To study the effects of treatment of Angle Ⅱ division 2 malocclusion with upper/lower arch expansion and Class Ⅱ elastics in adults. Methods:Expanding upper/lower arch and Class Ⅱ elastic were used to treat Angle Class Ⅱ division 2 malocclusion in 15 adults. Study models and cephalograms were analyzed before and after treatment. Results:Before and after treatment the maxillary variables of cephalograms showed no significant differences, the mandibular variables showed significant differences in sagittal and vertical direction. U1-NA, U1-PP, L1-NB, L1-MP, U1-L1 and L6-Ptm were significantly increased after treatment(P
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Objective: To investigate the expression of CSF-1 and TGF-?1 in periodontal tissue of third premolar germ during second primary molar orthodontic movement in dog. Methods: Orthodontic appliance with the force of 0.784 N for the mesial movement of mandible second primary molar was used in 4 dogs for 14 d.Then the samples including mandibular second and third molars and surrounding tissues were prepared for CSF-1 and TGF-?1 detection by immunohistochemical staining technique. Results: Strong CSF-1, TGF-?1 expression was found in the dental follicle and alveolar bone of mesial part of third premolar germ, and weak in the dental follicle and alveolar bone of distal part of third premolar germ in the treated side of the dogs. Conclusion: CSF-1 and TGF-?1 may play roles in the bone remodeling for orthodontic primary tooth movement.
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Objective:To study the effects of colony-stimulating factor-1 (CSF-1) on the expression of osteoprotegerin (OPG ) in human dental follicle cells.Methods:Human dental follicle cells culture was established and cell crawling slides were stained by OPG antibody. The third to sixth passage cells were incubated with 25 ng/ml CSF-1 for 0.5,1,3 and 6 h respectively,then the conditioned medium and cells were collected for ELISA and RT-PCR assay respectively.Results:OPG was expressed in the cytoplasm of human dental follicle cells.GSF-1 at 25 ng/ml and 1 h-exposure down-regulated OPG expression in the cells(P
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Objective:To investigate the third molar horizontal and vertical drift automatically after the second molar extraction.Methods: 26 patients,aged 11～18 years old, with the indications of second morlar extraction were divided into two groups:15 cases in experimental group with the extraction of the second molar and 11 in control group without the extraction. A cephalometric radiograph of each patient was traced on before and 9 months after treatment. Vertical and horizontal drift and mesio- angulation of the third molar were measured.Results:The third molar vertical mesio-movement (mm)in experimental and control groups was 7.08?2.04 and 2.09?0.47(P
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Objective To study the effect of different concentration of tumor necrosis factor-? (TNF-?) on expression of the receptor activator of nuclear factor-kappa B ligand (RANKL) and osteoprotegerin (OPG) mRNA on human dental follicle cells in vitro, and investigate the role of TNF-? in osteoclast formation during tooth eruption. Methods The 5th passage of primary cultured human dental follicle cells were treated with 0 (control group), 5, 10, 25, 50 and 100ng/ml TNF-?, respectively, for 6 hours. Total RNA was then isolated from human dental follicle cells and subjected to RANKL and OPG mRNA assay by reverse transcription-polymerase chain reaction (RT-PCR) technique. The relative expression levels of RANKL and OPG mRNA were normalized to ?-actin gene expression. Results The mRNA expression of OPG in human dental follicle cells with 5ng/ml TNF-? treatment was down regulated significantly compared with that in control group (P