• Restorative Dentistry and Endodontics
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• v.37 no.2
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• pp.114-118
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• 2012

Proximal caries or coronal defect in posterior teeth may result in the loss of proximal space and drifting of neighboring teeth, which makes restoration difficult. Inability to restore proper contours and to align tooth axis properly are commonly encountered problems when planning tooth restoration. Moreover, tilted teeth aggravate periodontal tissue breakdown, such as pseudo-pocket, and angular osseous defect. The purpose of this case presentation is to describe a simple technique for inducing minor tooth movement with orthodontic separating ring and provisional restoration modification. This method was used to create crown placement space on mesially tilted molar. This method is easy, simple and efficient technique which could be used in interproximal space gaining in selected situation.

• Korean Journal of Applied Biomechanics
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• v.20 no.1
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• pp.41-47
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• 2010

The purpose of this study was to evaluate the kinematic effect of upper extremity usage for the scoccer instep kick motion. Ten male university students were recruited as the subjects. Temporal parameters, ball velocity, velocity of CG, angle of segment, angular velocity, and trunk orientation angle were determined for each trial. The results showed that temporal parameters in WU and WORU were significantly less than those found in WOU during pre impact phase. These indicated that no usage of upper extremity may increase excessive setup time in order to improve the accuracy of instep kick. Angle of right knee in WOU at LC was significantly greater than corresponding value for WU since angular momentum contributions of the lower limb were not effectively balanced by contributions of the upper limb. We found that the lower extremity movement was controlled by lateral movement in the trunk as a result of no usage of the upper extremity, resulting in the relatively greater trunk rotation in WOU.

• Korean Journal of Applied Biomechanics
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• v.23 no.4
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• pp.369-376
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• 2013

The purposes of this study were to assess dynamic stability toward pelvis-spine column distortion during running and to compare the typical three-dimensional angular kinematics of the trunk motion; cervical, thoracic, lumbar segment spine and the pelvis from the multi-segmental spine model between exercise group and non-exercise group. Subjects were recruited as exercise healthy women on regular basis (group A, n=10) and non-exercise idiopathic scoliosis women (group B, n=10). Data was collected by using a vicon motion capture system (MX-T40, UK). The pelvis, spine segments column and lower limbs analysiaed through the 3D kinematic angular ROM pattern. There were significant differences in the time-space variables, the rotation motion of knee joint in lower limbs and the pelvis variables; obliquity in side bending, inter/outer rotation in twisting during running leg movement. There were significant differences in the spinal column that is lower-lumbar, upper-lumbar, upper-thoracic, mid-upper thoracic, mid-lower thoracic, lower thoracic and cervical spine at inclination, lateral bending and twist rotation between group A and group B (<.05, <.01 and <.001). As a results, group B had more restrictive motion than group A in the spinal column and leg movement behaved like a 'shock absorber". And the number of asymmetry index (AI) showed that group B was much lager unbalance than group A. In conclusion, non-exercise group was known to much more influence the dynamic stability of equilibrium for bilateral balance. These finding suggested that dynamic stability aimed at increasing balance of the trunk ROM must involve methods and strategies intended to reduce left/right asymmetry and the exercise injury.

• PNF and Movement
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• v.13 no.2
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• pp.81-88
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• 2015

Purpose: The purpose of this study was to analyze the effect of normal timing according to angular motion in PNF patterns on electromyography (EMG) activity in rectus abdominis, internal oblique abdominal muscle, external oblique abdominal muscle, and erector spinae. Methods: Ten healthy adults volunteered to participate in this study. The participants were required to complete following two PNF extremity patterns; upper extremity extension- adduction-internal rotation pattern with $180^{\circ}$, $90^{\circ}$, $30^{\circ}$ and lower extremity flexion- adduction-external rotation pattern with $0^{\circ}$, $60^{\circ}$, $90^{\circ}$. A paired t-test was used to determine the influence of the two PNF patterns on muscle activity in each muscle. Descriptive statistics were used to determine the ratio of local muscle activity to global muscle activity. Results: In terms of their effect on applied normal timing, the upper and lower extremity pattern significantly affected the rectus abdominis, internal oblique, external oblique, and erector spinae (p < .05). The upper extremity pattern (at an extension angle of $30^{\circ}$) and the lower extremity pattern ((at a flexion angle of $90^{\circ}$) influenced the rectus abdominis, internal oblique, external oblique, and erector spinae (p < .05). Conclusion: The effect of the upper and lower extremity patterns on applied normal timing was significant in that these patterns increased trunk muscle activation. The upper extremity pattern (at an extension angle of $30^{\circ}$) and the lower extremity pattern (at a flexion angle of $90^{\circ}$) increased trunk muscle activation. Normal timing is required to increase trunk muscle strength and extremity movement.

• International Journal of Advanced Culture Technology
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• v.7 no.1
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• pp.231-236
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• 2019

Background/Objectives: This paper proposes a dual mode feedback-controlled cycling system for children with spastic cerebral palsy to rehabilitate upper extremities. Repetitive upper limb exercise in this therapy aims to both reduce and analyze the abnormal torque patterns of arm movements in three- dimensional space. Methods/Statistical analysis: We designed an exercycle robot which consists of a BLDC motor, a torque sensor, a bevel gear and bearings. Mechanical structures are customized for children of age between 7~13 years old and induces reaching and pulling task in a symmetric circulation. The shafts and external frames were designed and printed using 3D printer. While the child performs active/passive exercise, angular position, angular velocity, and relative torque of the pedal shaft are measured and displayed in real time. Findings: Experiment was designed to observe the features of a cerebral palsy child's exercise. Two children with bilateral spastic cerebral palsy participated in the experiment and conducted an active exercise at normal speed for 3 sets, 15 seconds for each. As the pedal reached 90 degrees and 270 degrees, the subject showed minimum torque, in which the child showed difficulty in the pulling task of the cycle. The passive exercise assisted the child to maintain a relatively constant torque while visually observing the movement patterns. Using two types of exercise enabled the child to overcome the abnormal torque measured in the active data by performing the passive exercise. Thus, this system has advantage not only in allowing the child to perform the difficult task, which may contribute in improving the muscle strength and endurance and reducing the spasticity but also provide customizable system according to the child's motion characteristic. Improvements/Applications: Further study is needed to observe how passive exercise influences the movement characteristics of an active motion and how customized experiment settings can optimize the effect of pediatric rehabilitation for spastic cerebral palsy.

• The korean journal of orthodontics
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• v.49 no.6
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• pp.349-359
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• 2019

Objective: The aim of this study was to analyze three-dimensional (3D) changes in maxillary dentition in Class II malocclusion treatment using arch wire with continuous tip-back bends or compensating curve, together with intermaxillary elastics by superimposing 3D virtual models. Methods: The subjects were 20 patients (2 men and 18 women; mean age 20 years 7 months ${\pm}$ 3 years 9 months) with Class II malocclusion treated using $0.016{\times}0.022-inch$ multiloop edgewise arch wire with continuous tip-back bends or titanium molybdenum alloy ideal arch wire with compensating curve, together with intermaxillary elastics. Linear and angular measurements were performed to investigate maxillary teeth displacement by superimposing pre- and post-treatment 3D virtual models using Rapidform 2006 and analyzing the results using paired t-tests. Results: There were posterior displacement of maxillary teeth (p < 0.01) with distal crown tipping of canine, second premolar and first molar (p < 0.05), expansion of maxillary arch (p < 0.05) with buccoversion of second premolar and first molar (p < 0.01), and distal-in rotation of first molar (p < 0.01). Reduced angular difference between anterior and posterior occlusal planes (p < 0.001), with extrusion of anterior teeth (p < 0.05) and intrusion of second premolar and first molar (p < 0.001) was observed. Conclusions: Class II treatment using an arch wire with continuous tip-back bends or a compensating curve, together with intermaxillary elastics, could retract and expand maxillary dentition, and reduce occlusal curvature. These results will help clinicians in understanding the mechanism of this Class II treatment.

• Korean Journal of Applied Biomechanics
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• v.12 no.1
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• pp.221-231
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• 2002

The purpose of this study was to clarify the differences in service patterns of a forward and backward soft tennis players using 3D motion analyzer. Subjects were 4 forward players of $24.0\pm5.23$yrs and 4 backward players of $23.5\pm1.73$yrs. The results were as following: 1. There was no difference among each positions on swinging-time. The longest racket swinging-time was in the phase of takeback, the second one was in follow-through. The shortest one was in the phase of forward-swing so called force production phase, which had an influence on ball's velocity. 2. The racket speed on impact was 16.3m/s in forward subject and 19.53m/s in backward subject, when each velocity of balls was 44.6m/s, 52.9m/s. Although there was no significant difference along by positions, backward subject showed faster result. 3. The maximum speed of each performance was reached before the impact, and the speed at impact along by positions did not show any significant difference. The summation of velocity was measured in good order as following; hip, shoulder, elbow, wrist, top of racket. 4. In the angular velocity of all examine except one, the angular velocity of forearm was bigger than the one of racket top although there was no statistically significant difference between forward and backward subject. 5. The service grip of the forward players was shorter than that of backward players.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1160-1165
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• 2004

The purpose of this study was to calculate three dimensional angular displacements, moments and joint reaction forces of the ankle joint during the waist pulling, and to assess the ankle joint reaction forces according to different perturbation modes and different levels of perturbation magnitude. Ankle joint model was assumed 3-D ball and socket joint which is capable of three rotational movements. We used 6 cameras, force plate and waist pulling system. Two different waist pulling systems were adopted for forward sway with three magnitudes each. From motion data and ground reaction forces, we could calculate 3-D angular displacements, moments and joint reaction forces during the recovery of postural balance control. From the experiment using falling mass perturbation, joint moments were larger than those from the experiment using air cylinder pulling system with milder perturbation. However, JRF were similar nevertheless the difference in joint moment. From this finding, we could conjecture that the human body employs different strategies to protect joints by decreasing joint reaction forces, like using the joint movement of flexion or extension or compensating joint reaction force with surrounding soft tissues. Therefore, biomechanical analysis of human ankle joint presented in this study is considered useful for understanding balance control and ankle injury mechanism.

• Korean Journal of Applied Biomechanics
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• v.28 no.3
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• pp.193-197
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• 2018

Objective: The relationship between the rest intervals during physical tasks and performance enhancement has been studied. However, whether or not different rest intervals would result in altered multiplanar ankle kinematics during performance of the Star Excursion Balance Test (SEBT) is unknown. Method: Fifteen healthy subjects (7 males and 8 females) without a history of ankle injuries were participated in this study. 3 rest intervals of 10, 20, and 40 seconds were used during the current study. Three visits were required in order to complete the 3 rest intervals. Variables of interest included dorsiflexion (DF) excursion, tibial internal rotation (TIR), and eversion (EV) excursions. The means of ankle angular excursions were compared across the 3 directions in the 3 rest interval groups. Results: There were no significant main effects for any variables between restintervals. However, DF excursion in the anteromedial (AM) direction was greaterthan in both the medial (M) and posteromedial (PM) directions and was greater in the M direction compared to the PM direction. TIR excursion in the AM direction was less than in both the M and PM directions. Conclusion: Different rest intervals ranging from 10 to 40 seconds did not influence ankle angular excursions during the SEBT in a healthy population. However, our results suggest that multiplanar motion is necessary during the SEBT and differs depending on the direction of movement.

• Fisheries and Aquatic Sciences
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• v.9 no.4
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• pp.167-174
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• 2006

Two typical responses have been documented for flatfish when they encounter the ground gear of bottom trawls: herding response and falling back response. These two responses were analyzed from video recordings of fish and were characterized by time sequences for four parameters: swimming speed, angular velocity, acceleration, and distance between the fish and the ground gear. When flatfish displayed the falling-back response, absolute values of the three swimming parameters and their deviations were significantly higher than those during the herding response. However, the swimming parameters were not dependent on the distance between the flatfish and the ground gear, regardless of which response occurred. The dominant periods for most of the movement parameters ranged from 2.0 to 3.7 s, except that no periodicity was observed for swimming speed or angular velocity during the falling-back response. However, variations in the four parameters during the falling -back response revealed greater irregularity in periodicity and higher amplitudes. This complex behavior is best described as a chaos phenomenon' and is discussed as the building block for a model predicting the responses of flatfish to ground gear as part of the general understanding of the fish capture process.