• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.27 no.6
• /
• pp.570-575
• /
• 2001

This study evaluated the short-term outcome of treating fractures of the mandible with bioabsorbable plates. Thirty-four fractures of the mandible in 27 patients were treated by open reduction and internal fixation using bioabsorbable plates and 2.4-mm, 2.0-mm, and 1.5-mm pre-tapped screws. The duration of intermaxillary fixation ranged from 0 to 23 days, with a mean of 5.3 days. Patients were evaluated for complications during the follow-up period, which ranged from 2 to 18 months. Five patients(18.5%) experienced complications. These included infection (four patients), and premature occlusal contact(one patient). Except for one case, all complications were minor and adequately managed with incision and drainage, elastic traction, and medication. Delayed infection (osteomyelitis) developed in a symphysis fracture and was treated by saucerization and antibiotics. The fracture line subsequently showed complete consolidation. Bioabsorbable plates can be selectively used for internal fixation in mandibular fractures with the advantage that they do not need to be removed.

• Korean Journal of Cleft Lip And Palate
• /
• v.6 no.2
• /
• pp.131-135
• /
• 2003

Severe maxilla1y deficiency can be caused by cleft lip and palate(CLP), other craniofacial deformities, atrophy in the edentulous maxilla, and trauma. Patients with maxillary deficiency present a difficult treatment challenge. Traditionally, this skeletal deformity has been treated by Le Fort osteotomy, skeletal repositioning, and fixation with mini-plates and screws. The drawbacks of this method include a limited amount of anterior maxillary advancement often requiring simultaneous mandibular setback, the inability to create new bone, and minimal soft tissue adaptation to the new position, all of which increase the potential of relapse in case of large advancement. The alternative method of maxillary distraction osteogenesis offers promising results for successfully treatment of these patients while potentially minimizing the risk of relapse.

• The korean journal of orthodontics
• /
• v.47 no.4
• /
• pp.268-274
• /
• 2017

The purpose of this article is to introduce a simple appliance that uses a setup model and a nickel-titanium (Ni-Ti) wire for correcting the mesial rotation and drift of the permanent maxillary first molar. The technique involves bonding a Ni-Ti wire to the proper position of the target tooth on a setup model, followed by the fabrication of the transfer cap for indirect bonding and its transfer to the patient's teeth. This appliance causes less discomfort and provides better oral hygiene for the patients than do conventional appliances such as the bracket, pendulum, and distal jet. The treatment time is also shorter with the new appliance than with full-fixed appliances. Moreover, the applicability of the new appliance can be expanded to many cases by using screws or splinting with adjacent teeth to improve anchorage.

• Archives of Craniofacial Surgery
• /
• v.19 no.2
• /
• pp.143-147
• /
• 2018

We present a patient who showed a sterile abscess after facial bone fixation with bioabsorbable plates and screws. He had zygomaticomaxillary complex and periorbital fracture due to falling down. The displaced bones were treated by open reduction and internal fixation successfully using bioabsorbable plate system. However, at postoperative 11 months, abrupt painless swelling was noted on the previous operation sites, left lateral eyebrow and lower eyelid. By surgical exploration, pus-like discharge and degraded materials were observed and debrided. The pathologic analysis revealed foreign body reaction with sterile abscess. This complication followed by bioabsorbable device implantation on maxillofacial bone surgery has been rarely reported in which we call attention to the maxillofacial plastic surgeons.

• Journal of Institute of Control, Robotics and Systems
• /
• v.11 no.7
• /
• pp.609-614
• /
• 2005

Parallel manipulators have been used for a variety of applications, including the motion simulators and mechanism for precise machining. Since the ball screws used for linear motion of legs of the Stewart-Gough type parallel manipulator provide wider contact areas than revolute joints, parallel manipulators are usually more affected by frictional forces than serial manipulators. In this research, the method for detecting the frictional forces arising in the parallel manipulator using the gravitational force is proposed. First, the reference trajectories are computed from the dynamic model of the parallel manipulator assuming that it is subject to only the gravitational force without friction. When the parallel manipulator is controlled so that the platform follows the computed reference trajectory, this control force for each leg is equal to the friction force arising in each leg. It is shown that control performance can be improved when the friction compensation based on this information is added to the controller for position control of the moving plate of a parallel manipulator.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1997.04a
• /
• pp.1049-1052
• /
• 1997

The pupose of this study on the surface finishing is to examine the performance of brushing as a means of reducing the surface roughness of the precision theaded shafts in ball screw assemblies. Ball screws provide superior performance compared to other types of screw feeds in terms of static and dynamic rolling resistance,backlash,and wear characteristics. The Reduction of the surface roughness of the lead shaft in ball screw assembiles is essential for precision movement,high speed/low noise tracel, and for low wear/long life. To reduce machine dependent errors that would influence the surface roughness compared with other lapping or polishing techniques,experiments will be performed using special wire brushes to polish precision ground shafts. The best results were obtained using the Al /sab 2/O /sab3/ brushes, with the Al /sab 2/O /sab3/ #500 grit brush producing a surface finish of approximately 0.7 .mu.m, and the Al /sab 2/O /sab3/ #600 grit producing a surface finish of approximately 0.8 .mu.m. Both of these results were produced at the highest wheel polishing speed of 3520 rpm. The SiC #500 brush produced a surface roughness of approximately 1 .mu.m at 3520 rpm.

• Journal of the Korean Society for Precision Engineering
• /
• v.32 no.6
• /
• pp.503-507
• /
• 2015

In this study, we compare the performance of the screw through the Clamping force of the test materials to change shape and structure, one of the ways to maintain and improve the engaging force to cope with the miniaturization of the fastener threads are further thinner and lighter precision way that can improve the fastening force of the screw results were as follows. The clamping force according to the materials was $7.57N{\cdot}cm$ in SUS XM7 and SWCH18A was $5.97N{\cdot}cm$. This result was to be found to average 13.5% high in the Clamping force of SUS XM7 materials. In the case of the clamping force of the screw thread shape change, the clamping force of symmetrical and asymmetrical thread was $6.78N{\cdot}cm$ and $7.57N{\cdot}cm$. The clamping force of the asymmetrical thread showed an average high of 11.6%.

• Clinics in Shoulder and Elbow
• /
• v.11 no.1
• /
• pp.62-65
• /
• 2008

Isolated acromial fracture is not common and it frequently accompanies fractures to the coracoid process and glenoid bone and also injuries to the acromioclavicular joint. Furthermore, most of these combined acromial fractures have minimal displacement, which needs no additional treatment other than protection for a certain period of time. We have experienced a case of isolated fracture of the posterolateral angle of the acromion, which we reduced and fixated using K-wire and cannulated screws. We report on the technical aspects and clinical results of this reduction and fixation, along with a review of the literature.

• Journal of the Korean Wood Science and Technology
• /
• v.40 no.6
• /
• pp.363-369
• /
• 2012

Shear tests parallel to the grain were conducted on domestic wood samples with different growth ring orientations. Shear strength was dependent on the angles between the direction of growth ring orientation and the applied force. The maximum shear strength showed at the intermediate growth ring orientations. Results of shear tests were also used to modify the formula which had previously been developed to predict the withdrawal strength of screw on the face of lumber. Predicted equations were fitted to the results of previous study with different length of No. 8 screw. Predicted equation was under-predicted the withdrawal strength of 25 and 30 mm length of screw within 8% and over-predicted withdrawal strength of 18 and 38 mm length of screw. A little differences between the predicted by shear strength with different growth ring orientation and observed values was existed.

• Journal of the Institute of Electronics Engineers of Korea SC
• /
• v.46 no.3
• /
• pp.1-7
• /
• 2009

This paper suggests an automatic electrophoretic deposition (EPD) robot system using a color mono camera. The EPD robot system consists of a 2 DOF rectangular robot to practically carry out EPD tasks, and a color mono camera to automatically control the robot. The screws are used to actuate the robot with low speed of 10mm/s for EPD tasks. The color mono camera detects the color marks attached to the robot and beakers, and obtains their positions. The obtained positions are used for automatic robot control. Also, the camera recognizes the combinations of the markers attached to the beakers, and determines the selected EPD task among various predetermined EPD tasks with different working parameters. Finally, experimental results are shown for verifying the effectiveness of the suggested EPD robot system.