169 subjects with ages ranging from 6 to 25 years with maloposition and rotation of teeth were treated in the Institute of odontostomatology and maxilofaciology, Hanoi. The aim of this study was to show the most reasons that cause maloposition and rotation of teeth for these reasons, the children from school age is needed to be seen by the orthodontisis every 6 months to prevent maloposition
Orthodontics ; Rotation

OBJECTIVETo further explore the best Forsus load power by analyzing the change of mandible's stress and displacement after Forsus protruded mandible instantaneously under different vertical component for providing theoretical basis.

METHODSThe pre-built Forsus protruding mandible model were build through Abaqus 6.5 software. The change of mandible's stress, displacement, and pathway trend under three different working conditions(horizontal component 4 N and vertical component 2, 4, 1 N).

RESULTSTorsion occurred in all condyles under three working conditions, and the stress was large. Under vertical component 2 and 1 N, the mandible demonstrated counterclockwise rotation, the maximum displacement occurred in the chin, respectively 1.150 mm and 2.141 mm; under vertical component 4 N, mandible rotation was not obvious, the maximum displacement of chin was only 0.188 mm.

CONCLUSIONWith the vertical component gradually decreased, the protrusion trend of chin increased; Forsus could promote the mandible counterclockwise rotation and modification when protruding mandible.

The paper introduces a new design of the CT rotation motion control system. The system is controlled by a variable frequency drive as a controller and a general induction motor as an actuator. In addition, this paper also introduced the model selection of CT rotating control device and the parameters setup for variable frequency drive. Meanwhile, a test method of the rotor position servo control system is also introduced at the end of the paper. The new system has lowcost, high-performance features, fully meets the requirement of CT rotation motion control.
Equipment Design ; Rotation ; Tomography, X-Ray Computed

OBJECTIVE: Develop an intelligent equipment that can perform multiple modes of functional exercise on the knee joint, and can accurately measure and control strength, angle, angular velocity, time, frequency and so on. METHODS: Using geared motors, magnetic powder brakes and synchronous belt wheel sets and other mechanical structure and transmission technology combined with sophisticated mechanical design methods, the knee joint multiple functional exercise methods are cleverly integrated; a highly reliable PLC is used as the control core; the resistance torque out-put by the equipment is accurately controlled by adjusting the size of the exciting current; the angle sensor is used to accurately measure the rotation angle around the axis; and the error of each parameter index and the actual measured value is controlled within 5%. RESULTS: The developed prototype has a compact structure and a simple and convenient method of use. Based on the control of joint parameters such as resistance, the expected goal is achieved. CONCLUSIONS The equipment can carry out diversified, accurate and automatic rehabilitation treatment for knee joint diseases, and has certain social and economic benefits.
Biomechanical Phenomena ; Knee Joint ; Powders ; Rotation ; Torque

The theories and clinical and experimental studies about reinforcing-reducing manipulation of twirling rotating the needle in recent 15 years are reviewed and a brief account of manipulation methods, mechanisms and effects of reinforcing-reducing manipulation of twirling-rotating the needle is given, and it is indicated that the following several aspects in the studies at present need to be completed. Standardization and establishment of national standard of acupuncture manipulation must be enforced; quantitative parameters of acupuncture manipulation and mechanisms of acupuncture reinforcing-reducing of twirling-rotating the needle need to be further studied.
Acupuncture Therapy ; methods ; Humans ; Needles ; Rotation

Humans ; Rotation ; Tennis Elbow ; therapy ; Traction ; methods

HX straight-wire appliance (HX-SWA) is designed and adjusted by doctors of Orthodontic Department, West China College of Stomatology, Sichuan University. It is a set of appliance that is constructed according to normal occlusion features of the Chinese people, including the prescription of tip, torque, in/out, counter-tip, counter-rotation and overcorrection in brackets and buccal tubes. Some ingredients of the appliance are different from that of the most popular Roth straight-wire appliance in the world wide. Over a period of the last 10 years, doctors in our hospital kept on summarizing treatment experience with HX-SWA, which will help more doctors promote practice and results in orthodontic clinic.
Dental Occlusion ; Humans ; Orthodontic Wires ; Rotation

OBJECTIVETo evaluate the mandibular rotation in females aged from 9.5 to 15.5 years.

METHODSThe sample was obtained from Mathews's implant study with longitudinal cephalometric records of 13 untreated Caucasian female subjects. The cephalograms taken annually from 9.5 to 15.5 years old were traced and analyzed with Dentofacial Software. Paired-t test was performed to identify the significant growth changes in different age groups.

RESULTSSignificant change in lower anterior facial height, posterior facial height, ramus length and mandibular implant plane angle were noted in aged 9.5-11.5. Significant change in lower anterior facial height, posterior facial height and ramus length were noted in aged 11.5-13.5. Significant change in mandibular plane angle and mandibular implant plane angle and significant increase in posterior facial height were observed in aged 13.5-15.5.

CONCLUSIONThe results of this study verify that remodeling on the lower border of mandible influences total mandibular rotation.

This paper is aimed to develop a computerized three dimensional system for displaying and analyzing mandibular helical axis pathways. Mandibular movements were recorded using a six-degrees-of-freedom ultrasonic jaw movement recording device. The three-dimensional digital models of the midface and the mandible were reconstructed and segmented from CT skull images. The digital models were then transformed to the coordinate system of mandibular motion data by using an optical measuring system. The system was programmed on the base of the Visualization ToolKit and Open Scene Graphics Library. According to the motion data, transformation matrices were calculated to simulate mandibular movements. Meanwhile, mandibular helical axis pathways were calculated and displayed three dimensionally by means of an eigenvalues method. The following parameters of mandibular helical axis were calculated: the rotation around instantaneous helical axis, the translation along it, its spatial orientation, its position and distance relative to any special reference point. These parameters could be exported to describe comprehensively the whole mandiblular movements. It could be concluded that our system would contribute to the study of mandiblular helical axis pathways.
Humans ; Imaging, Three-Dimensional ; Mandible ; Models, Anatomic ; Movement ; Rotation

This study proposed a method to calibrate tube focus spot and the center plane of rotation in computed tomography system. In the method, the tube was rotated to 0° and 180° respectively, and then one metal jig with symmetric windows A and B was scanned at each position under the tube cool and static condition. According to the geometry of tube focus spot, aperture center of the collimator and jig, the distance between tube focus spot and the center plane of rotation were calculated with the X ray transmittance data after denoising, mean value and normalization. To verify the practicability and validity of the method, the tube focus spot in a 16 slices CT system (Brivo CT385, GE, China) was calibrated, and the result after calibration was validated by scanning a polaroid film. The validation result showed that the deviation between tube focal spot and center plane of rotation was 0.02 mm and was in the error range within ± 0.1 mm. The results of this study showed that, as a simple and low-cost design, the method could be used for fast calibration between tube focus spot and the center plane of rotation.
Calibration ; Rotation ; Tomography, X-Ray Computed ; X-Rays