ABSTRACT
BACKGROUND:A new open“C”-shaped molar band with nanocoating (patent number:ZL201110057699.1) has been invented to overcome some weakness of traditional bands and buccal tubes, which is used for molar fixation. OBJECTIVE:Using three-dimension finite element analysis software to theoretical y prove that the new band comes up to clinic requirement. METHODS:We established a finite element model of alveolar bone-tooth-band, and node domains tensile and shear loading were given. Stress distribution of the new bands through numerical simulation was predicted and calculated. Simulation of 20 N orthodontic force was applied in medial direction, distal direction and vertical direction in the three-dimensional model of a new band buccal tube and traditional band, to analyze the stress state in different directions under the force of the binder. RESULTS AND CONCLUSION:By numerical simulation of three-dimensional finite element, the stress of the new band was higher than that of the traditional band, but it could not reach the clinical cracking limit of resin reinforced glass ionomer cement. So the new band could theoretical y satisfy the clinical requirements.
ABSTRACT
BACKGROUND: Imported self-locking brackets cost much. So it is necessary to develop low-cost and easy-to-operate domestic self-locking brackets.OBJECTIVE: To introduce a newly developed self-locking brackets, and investigate the frictional forces of the brackets. DESIGN, TIME AND SETTING: Biomechanical controlled analysis was performed in the Laboratory of Harbin Medical University in January 2004. MATERIALS: Self-made self-locking brackets and domestic conventional tie-wing stainless steel brackets; domestic Ni-Ti round wire, Australian stainless steel round wire, and domestic stainless steel rectangular wire. METHODS: Two kinds of brackets were combined with three kinds of arch wires. Under the drive of micromotor, pull sensor moved at 1 mm/min. An arch wire, which was ligated in the bracket, was dragged. Thus, teeth's shift was imitated.MAIN OUTCOME MEASURES: Waveshape was observed through the use of storage oscillograph and corresponding data were recorded. Frictional force was determined and compared.RESULTS: Under the same other conditions, no matter which kind of arch wires were combined with, tie-wing brackets produced greater frictional force than self-locking brackets (P < 0.001). Under the same other conditions, no matter which kind of brackets were combined with, Ni-Ti wire produced greater frictional force than Australian stainless steel round wire and domestic stainless steel rectangular wire (P < 0.001). In addition, domestic stainless steel rectangular wires produced greater frictional force than Australian stainless steel round wires (P < 0.001). CONCLUSION: Self-locking bracket produces low frictional force, so it is fit for orthodontic doctors to use the corrective force.
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Objective:To study the effect of articulation disorder on psychology action of cleft palate patients after operation.Methods:65 patients were asked to answer the psychology questionnaire.Results:The patients of misarticulation all have some degree of psychological disability,and unusual psychology action would affect pronunciation treatment.Conclusion:Patients with misarticulation have psychology problems in some degree,which would affect the clinic treatment of cleft palate.
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OBJECTIVE:To establish an optimal therapeutic window concentration of CsA trough levels in renal transplant recipients on triple immunosuppressants regimen METHODS:A total 1 874 samples from 268 renal transplant recipients were measured by fluorescence polarization immunoassay(FPIA) According to the duration after operation and clinical diagnoses ,the whole blood CsA trough levels were compared among subgroups RESULTS:The optimal therapeutic window concentration of CsA was 300～400?g/L(within 1 month after operation),250～350?g/L(2nd～3rd month),150～250?g/L(4th～6th month),100～200?g/L(7th～12th month)and 100～150?g/L(more than 12 months) CONCLUSION:The above mentioned therapeutic window concentratin of CsA trough levels was ideal for renal transplant recipients with no marked acute toxic effects and rejection reaction