• The Journal of Korean Academy of Prosthodontics
• /
• v.22 no.1
• /
• pp.17-22
• /
• 1984

A clinical evaluation was made on teeth in 113 subjects from ages 19 to 23 with Angle's Class I occlusion who were free from prosthesis, orthodontics, and occlusal equilibration. The study was made to determine if there was a relation between the type of occlusion, non-working contact and temporomandibular dysfunction. From the foregoing study, the author obtained the following results. 1. In lateral excursion, there was not any significant difference between bilateral canine protected occlusion (31%), bilateral group function (32.7%), and mixed type (34.5%). 2. Only 10 of 113 subjects studied had non-working side tooth contacts (8.2 per cent). 3. Twenty per cent of subjects with non-working side contact showed temporomandibular joint dysfunction. 4. Non-working side contacts were not observed in subjects with canine guided occlusion. 5. It would be premature to relate the type of occlusion on working side directly to temporomandibular joint dysfunction.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.06a
• /
• pp.1944-1947
• /
• 2005

In this paper, the control of a prosthetic arm using the flex sensor signal is described. The flex sensors are attached to the biceps and triceps brchii muscle. The signals are passed a differential amplifier and noise filter. And then the signals are converted to digital data by PCI 6036E ADC. From the data, position and velocity of arm joint are obtained. Also motion of the forearm - flexion and extension, the pronation and supination are abstracted from the data by proposed algorithm. A two D.O.F arm with RC servo-motor is designed for experiment. The arm length is 200 mm, weight is 4.5 N. The rotation angle of elbow joint is $120^{\circ}$. Also the rotation angle of the wrist is $180^{\circ}$. Through the experiment, we verified the possibility of the prosthetic arm control using the flex sensor signal. We will try to improve the control accuracy of the prosthetic arm continuously.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.38
• /
• pp.39.1-39.6
• /
• 2016

Background: Temporomandibular joint (TMJ) ankylosis in children often leads to facial deformity, functional deficit, and negative influence of the psychosocial development, which worsens with growth. The treatment of TMJ ankylosis in the pediatric patient is much more challenging than in adults because of a high incidence of recurrence and unfavorable growth of the mandible. Case report: This is a case report describing sequential management of the left TMJ ankylosis resulted from trauma in early childhood. The multiple surgeries including a costochondral graft and gap arthroplasty using interpositional silicone block were performed, but re-ankylosis of the TMJ occurred after surgery. Alloplastic TMJ prosthesis was conducted to prevent another ankylosis, and signs or symptoms of re-ankylosis were not found. Additional reconstruction surgery was performed to compensate mandibular growth after confirming growth completion. During the first 3 years of long-term follow-up, satisfactory functional and esthetic results were observed. Conclusions: This is to review the sequential management for the recurrent TMJ ankylosis in a growing child. Even though proper healing was expected after reconstruction of the left TMJ with costal cartilage graft, additional surgical interventions, including interpositional arthroplasty, were performed due to re-ankylosis of the affected site. In this case, alloplastic prosthesis could be an option to prevent TMJ re-ankylosis for growing pediatric patients with TMJ ankylosis in the beginning.

• The Journal of Korean Academy of Prosthodontics
• /
• v.44 no.1
• /
• pp.85-102
• /
• 2006

Statement of problem: Currently, there are some 20 different geometric variations in implant/abutment interface available. The geometry is important because it is one of the primary determinants of joint strength, joint stability, locational and rotational stability. Purpose: As the effects of the various implant-abutment connections and the prosthesis height variation on stress distribution are not yet examined this study is to focus on the different types of implant-abutment connection and the prosthesis height using three dimensional finite element analysis. Material and method. The models were constructed with ITI, 3i TG, Bicon, Frialit-2 fixtures and solid abutment, TG post, Bicon post, EstheticBase abutment respectively. And the super structures were constructed as mandibular second premolar shapes with 8.5 mm, 11 mm, 13.5 mm of crown height. In each model, 244 N of vertical load and 244 N of $30^{\circ}$ oblique load were placed on the central pit of an occlusal surface. von Mises stresses were recorded and compared in the crowns, abutments, fixtures. Results: 1. Under the oblique loading, von Mises stresses were larger in the crown, abutment, fixture compared to the vertical loading condition. 2. The stresses were increased proportionally to the crown height under oblique loading but showed little differences with three different crown heights under vertical loading. 3. In the crown, the highest stress areas were loading points under vertical loading, and the finish lines under oblique loading. 4. Under the oblique loading, the higher stresses were located in the fixture/abutment interface of the Bicon and Frialit-2 systems compared to the ITI and TG systems. Conclusions: The stress distribution patterns of each implant-abutment system had difference among them and adequate crown height/implant ratio was important to reduce the stresses around the implants.

• Hip & pelvis
• /
• v.35 no.1
• /
• pp.40-46
• /
• 2023

Purpose: A variety of short Exeter stems designed specifically for use in performance of total hip arthroplasty (THA) in primary and revision settings have recently been introduced. Some have been used 'off label' for hip reconstruction. The aim of this study is to report clinical and radiological results from the Exeter V40 125 mm stem in performance of primary THA and revision THA. Materials and Methods: This study had a retrospective design. Insertion of 58 (24 primary, 34 revision) Exeter V40 125 mm stems was performed between 2015 and 2017. The minimum follow-up period was two years. Assessment of the Oxford hip score (OHS), EuroQol-5 Dimension (EQ-5D), and radiological follow-up was performed at one and two years. Results: In the primary group, the preoperative, mean OHS was 13.29. The mean OHS was 32.86 and 23.39 at one-year and two-year post-surgery, respectively. The mean EQ-5D-3L scores were at 0.14, 0.59, and 0.35, preoperatively, at one-year follow-up and two-year follow-up, respectively. In the revision group, the mean preoperative OHS was 19.41. The mean OHS was 30.55 and 26.05 at one-year and two-year post-surgery, respectively. The mean EQ-5D-3L scores were 0.33, 0.61, and 0.48 preoperatively, at one-year follow-up and two-year follow-up, respectively. No progressive or new radiolucent lines were observed around any stem at the time of the final follow-up in all patients in both groups. Conclusion: Encouraging results regarding use of Exeter V40 125 mm stems have been reported up to two years following surgery in primary and revision THA settings.

• International Journal of Precision Engineering and Manufacturing
• /
• v.9 no.1
• /
• pp.30-33
• /
• 2008

Understanding the characteristics of amputee gait is key in developing more advanced prostheses. The aim of this study was to quantitatively analyze a stair-climbing task for transfemoral amputees with a prosthesis and to predict the muscle forces and joint moments at musculoskeletal joints using a dynamic analysis. A three-dimensional musculoskeletal model of the lower extremities was constructed from a gait analysis using transformation software for two transfemoral amputees and ten healthy people. The measured ground reaction forces and kinematical data of each joint from the gait analysis were used as input data for an inverse dynamic analysis. Dynamic analyses of an transfemoral amputee climbing stairs were performed using musculoskeletal models. The results showed that the summed muscle forces of the hip extensor of an amputated leg were greater than those of a sound leg. The opposite was true at the hip abductor and knee flexor of an amputated leg. We also found that higher moments at the hip and knee joints of the sound leg were required to overcome the flexion moment caused by the body weight and amputated leg. Dynamic analyses using musculoskeletal models may be a useful means to predict muscle forces and joint moments for specific motion tasks related to rehabilitation therapy.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2005.11a
• /
• pp.891-894
• /
• 2005

This paper describes a human finger model driven by shape memory alloy(SMA) wires. The finger model has three joints that are similar to human finger. Each joint is actuated with two wires in the antagonistic manner and six wires are used to actuate three finger joint. In order to obtain the desirable finger motion, the diameters of the SMA wires are designed with different diameters by considering the required actuating force and response time. The rotary sensors are used to measure the angle positions of the joints and PWM control using PID algorithm is used to achieve desired angle positions of the finger joints. After estimating the control performance of each finger joint for the desired angle position, the antagonistic motion control of the finger model is experimentally evaluated.

• The Korean Journal of Pain
• /
• v.23 no.4
• /
• pp.258-261
• /
• 2010

We report a 66-year-old woman with complex regional pain syndrome (CRPS) 1 treated with combined medical and active physical therapy. She was diagnosed with CRPS 1 following partial shoulder prosthesis due to proximal humerus fracture. Despite continuous medication and physical therapy, there was no improvement in her pain and functional outcome. Her overall pain was decreased by stellate ganglion block 3 times in two weeks conducted during the second month of the follow-up period. Following the ganglion blockades, pain and the other symptoms were decreased intermittently but range of motion (ROM) and functional status were not satisfied as much as expected. After the third month of follow-up, her passive and active ROM of the shoulder joint was increased after application of manipulation under general anesthesia. In conclusion, because CRPS 1 remains one of the most difficult pain syndromes, early diagnosis and treatment are important to have adequate functional results from physical therapy. Manipulation under general anesthesia may be an additional effective treatment tool to obtain functional improvement in some patients diagnosed with CRPS 1.

• Structural Engineering and Mechanics
• /
• v.88 no.6
• /
• pp.583-588
• /
• 2023

Total hip replacement is a crucial intervention for patients with fractured hips who face challenges in natural recovery. The design of durable prostheses requires a comprehensive understanding of the natural processes occurring in bone. This article focuses on static loading analysis, specifically during stumbling activity, aiming to enhance the longevity of prosthetic implants. Three distinct implants, Charnley, Osteal, and Thompson, were selected for a detailed study to determine the most appropriate model. The results revealed critical insights into the distribution of Von Mises stresses on the components of femoral arthroplasty, including the cement, implant, and cortical bone. Furthermore, the examination of shear stress within the cement emerged as a pivotal aspect for all three implants, playing a crucial role in evaluating the performance and durability of hip prostheses. The conclusions drawn from this study strongly suggest that the Thompson model stands out as the most suitable choice for hip joint implants.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.47 no.4
• /
• pp.239-248
• /
• 2021

The paper reviews various classifications and surgical techniques for the treatment of temporomandibular joint ankylosis. PubMed, EBSCO, Web of Science, and Google Scholar were searched using a combination of keywords. Articles related to classification, resection-reconstruction of the temporomandibular joint, and management of airway obstruction were considered and categorized based on the objectives. Seventy-nine articles were selected, which included randomized clinical trials, non-randomized controlled cohort studies, and case series. Though several classifications exist, most classifications are centered on the radiographic extent of the ankylotic mass and do not include the clinical and functional parameters. Hence there is a need for a comprehensive staging system that takes into consideration the age of the patient, severity of the disease, clinical, functional, and radiographic findings. Staging the disease will help the clinician to adopt a holistic approach in treating these patients. Interpositional arthroplasty (IA) results in better maximal incisal opening compared with gap arthroplasty, with no significant difference in recurrent rates. Distraction osteogenesis (DO) is emerging as a popular technique for the restoration of symmetry and function as well as for relieving airway obstruction. IA, with a costochondral graft, is recommended in growing patients and may be combined with or preceded by DO in cases of severe airway obstruction. Alloplastic total joint replacement combined with fat grafts and simultaneous osteotomy procedures are gaining popularity. A custom-made total joint prosthesis using CAD/CAM can efficiently overcome the shortcomings of stock prostheses.