• Proceedings of the KOSOMBE Conference
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• v.1991 no.05
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• pp.39-42
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• 1991

Two types of speech signal processores (SSP) for cochlea prosthesis are designed. One is designed using cochlear model and the other is designed using Information (formant, pitch, intensity) extraction method. For these, cochlear model and acoustic information extraction method are proposed. The result shows SSP of cochlear model type contain more acoustic cues than that of information extraction type.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.247-249
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• 2007

This paper proposes a dry-type surface myoelectric sensor for the myoelectric hand prosthesis. The designed surface myoelectric sensor is composed of skin interface and processing circuits. The skin interface has one reference and two input electrodes, and the reference electrode is located in the center of two input electrodes. Considering the conduction velocity and the median frequency of the myoelectric signal, the inter-electrode distance (IED) between two input electrodes as 18mm, 20mm, and 22mm is selected. The signal processing circuit consists of a differential amplifier with a band pass filter, a band rejection filter for rejecting 60㎐ power-line noise, amplifier, and a level circuit. Using SUS440, six prototype skin interface with different reference electrode shape and IED is fabricated, and their output characteristics are evaluated by output signal obtained from the forearm of a healthy subject. The experimental results show that the skin interface with parallel bar shape and the 18mm IED has a good output characteristics. The fabricated dry-type surface myoelectric sensor is evaluated for the upper-limb amputee.

• The Journal of the Korean bone and joint tumor society
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• v.17 no.2
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• pp.79-86
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• 2011

Purpose: Modular tumor prosthesis is the most popular recontructive modality after resection of malignat tumor in extremity. Complications and survival of tumor prosthesis reconstruction are well-known. however, reports on the long-term outcome of tumor prosthesis in osteosarcoma patientss are scarece. Materials and Methods: In 158 cases as diagnosed as osteosarcoma from feburary 1989 to December 2006 in a single cancer center. We retrospectively reviewd 48 osteosarcoma patients who under went tumor prosthetic reconstruction. Mean follow up preiod was 75.6 months (range; 60 to 179 months). There were 28 males, 20 females and mean age was 22.4 years (range; 11-71). Pathologic subtypes were conventional central osteosarcoma in 46 cases and periosteal in 2 cases. The location of the tumor was proximal tibia (26 cases), distal femor (20 cases), femor diaphysis (1 case), and tibia diaphysis (1 case). In 41 cases built-up-type tumor prosthesis have been used and 7 cases expansion-type tumor prosthesis have been used. We used Musculoskeletal tumor society (MSTS) grading system to asses post operation function, and we analyzed survival rate of patient and tumor prosthesis and complication. Results: The overall survival rate was 77.7% and disease free survival rate was 68.9%. The survival rate of tumor prosthesis was 73%, in last follow up tumor prosthesis has been removed in 12 cases. All of them, 17 complications occurred, which included infection in 16 cases, Periprosthetic Fracture and Loosening of tumor prosthesis in 4 cases, articular instability in 4 cases. MSTS functional score was 74.1% in post operation. Conclusion: In long term follow up result, Primary tumor prosthesis -a reconstruction method after a wide extensional resecion of a bone tumor- can be a effective treatment method in asepect of survival rate, functional assesment and complication.

• Journal of Chest Surgery
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• v.27 no.10
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• pp.862-867
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• 1994

We experienced two cases of dissecting aneurysm[DeBakey type III] of the thoracic aorta treated using intraluminal sutureless graft. Controversy still exists about the exact timing of surgical intervention for dissection of the descending thoracic aorta. The surgical indication of dissecting aneurysm[DeBakey type III] is continuous flow in the false lumen, continuous chest pain, compromise of arterial supply to a specific organ or limb, or extension of the dissection while the patient is receiving satisfactory medical treatment. Surgical therapy for dissection of the aorta has had a high mortality. One contributing factor has been hemorrhage from the prosthesis and the suture lines. Recently, a new method of treatment with a intraluminal sutureless graft that requires no end-to-end anastomosis has been developed. In our cases, cardiopulmonary bypass and circulatory arrest was utilized in repairing dissecting aneurysm of descending aorta[DeBakey type III] in order to avoid the aortic cross clamping because of friable aortic intima. The basic technique consists of vertical incision of descending aorta in the area of intimal tear and inserting the whole ringed graft into the true lumen of the dissected aorta and circumferentially ligating the aorta against the groove in the rings. Postoperative course was uneventful.

• The Journal of Korean Academy of Prosthodontics
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• v.40 no.4
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• pp.374-385
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• 2002

A total of 605 implant fixture prosthesis delivered by 3 clinics and 2 laboratories were examined in this study, The object of this study was to determine the proper length of screw head. The depth of access hole were measured and compared to the type of fixture, abutment, gold screw and prosthesis. The results were as follows : 1 The average number of fixtures per patient were 2.97. 2. The number of fixture installed in the upper posterior area are 327(55.56 %), the upper posterior area 171 (28.25%). 3. The depth of access hole is 4.23 mm in shallow area, and 5.46 mm in deep area and the differences were 1.23 mm. 4. The average depth of the aceess hole of the UCLA abutment were 5.02 mm. 5. The number of 4-5 mm access hole depth were 60(22.39%) in abutment screw level and the number of 4-5 mm depth in fixture level were 101 (29.19%). 6. In the shape of screw head, hexed type were 576(95.21%), slotted type were 29(4.79%).

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.55 no.12
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• pp.550-557
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• 2006

This paper proposes a dry-type surface myoelectric sensor for the myoelectric hand prosthesis. The designed surface myoelectric sensor is composed of skin interface and processing circuits. The skin interface has one reference and two input electrodes, and the reference electrode is located in the center of two input electrodes. In this paper is proposed two types of sensors with the circle- and bar-shaped reference electrode, but all input electrodes are the bar-shaped. The metal material of the electrodes is the stainless steel (SUS440) that endures sweat and wet conditions. Considering the conduction velocity and the median frequency of the myoelectric signal, the inter-electrode distance (IED) between two input electrodes as 18mm, 20mm, and 22mm is selected. The signal processing circuit consists of a differential amplifier with a band pass filter, a band rejection filter for rejecting 60Hz power-line noise, amplifiers, and a mean absolute value(MAV) circuit. Using SUS440, six prototype skin interface with different reference electrode shape and IED is fabricated, and their output characteristics are evaluated by output signal obtained from the forearm of a healthy subject. The experimental results show that the skin interface with parallel bar shape and the 18mm IED has a good output characteristics. The fabricated dry-type surface myoelectric sensor is evaluated for the upper-limb amputee.

• The Journal of Korean Academy of Prosthodontics
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• v.51 no.2
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• pp.107-112
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• 2013

Complications increases when crown height space is excessive and one should be careful of choosing type of fixed prosthesis in case crown height space is over 12 mm. In this condition, tooth seems to be longer, therefore, it is needed to use gingival shade in aesthetically important area for fixed prosthesis. In this case, fixed prosthesis which has inappropriate maintenance and hygiene could hold food, plaque, calculus, thus increase incidence of inflammation and infection. Moreover, it could lead to chronic inflammation and infection and in that case surgical improvement could be necessary. In present case report, gingival inflammation and swelling developed around prosthesis after having made it considering articulation and aesthetic view in patient who had excessive crown height space. Finding out that design of prosthesis is a factor to make it hard to maintain oral hygiene, a temporary prosthesis which has enough interproximal space and proper emergence profile was fabricated. After two months of observation, significant abnormal symptoms are not found and oral reconstruction is performed using fixed prosthesis with zircornia infrastructure and porcelain build-up based on convenient self hygiene design. Through serial treatment, inappropriate soft tissue response is not observed and satisfactory result in functional aspect comes out.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2011.05a
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• pp.165-166
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• 2011

conical type의 sputtering 시스템으로 3차원 치과 보철물 위에 균일한 Ti 박막의 증착을 시도하였으며, 증착 변수에 따른 Ti 박막의 특성을 조사하였다.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.3
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• pp.290-297
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• 2008

STATEMENT OF PROBLEM: Implant-supported fixed cantilever prostheses are influenced by various biomechanical factors. The information that shows the effect of implant number and position of cantilever on stress in the supporting bone is limited. PURPOSE: The purpose of this study was to investigate the effect of implant number variation and the effect of 2 different cantilever types on stress distribution in the supporting bone, using 3-dimensional finite element analysis. MATERIAL AND METHODS: A 3-D FE model of a mandibular section of bone with a missing second premolar, first molar, and second molar was developed. $4.1{\times}10$ mm screw-type dental implant was selected. 4.0 mm height solid abutments were fixed over all implant fixtures. Type III gold alloy was selected for implant-supported fixed prostheses. For mesial cantilever test, model 1-1 which has three $4.1{\times}10$ mm implants and fixed prosthesis with no pontic, model 1-2 which has two $4.1{\times}10$ mm implants and fixed prosthesis with a central pontic and model 1-3 which has two $4.1{\times}10$ mm implants and fixed prosthesis with mesial cantilever were simulated. And then, 155N oblique force was applied to the buccal cusp of second premolar. For distal cantilever test, model 2-1 which has three $4.1{\times}10$ mm implants and fixed prosthesis with no pontic, model 2-2 which has two $4.1{\times}10$ mm implants and fixed prosthesis with a central pontic and model 2-3 which has two $4.1{\times}10$ mm implants and fixed prosthesis with distal cantilever were simulated. And then, 206N oblique force was applied to the buccal cusp of second premolar. The implant and superstructure were simulated in finite element software(Pro/Engineer wildfire 2.0). The stress values were observed with the maximum von Mises stresses. RESULTS: Among the models without a cantilever, model 1-1 and 2-1 which had three implants, showed lower stress than model 1-2 and 2-2 which had two implants. Although model 2-1 was applied with 206N, it showed lower stress than model 1-2 which was applied with 155N. In models that implant positions of models were same, the amount of applied occlusal load largely influenced the maximum von Mises stress. Model 1-1, 1-2 and 1-3, which were loaded with 155N, showed less stress than corresponding model 2-1, 2-2 and 2- 3 which were loaded with 206N. For the same number of implants, the existence of a cantilever induced the obvious increase of maximum stress. Model 1-3 and 2-3 which had a cantilever, showed much higher stress than the others which had no cantilever. In all models, the von Mises stresses were concentrated at the cortical bone around the cervical region of the implants. Meanwhile, in model 1-1, 1-2 and 1-3, which were loaded on second premolar position, the first premolar participated in stress distribution. First premolars of model 2-1, 2-2 and 2-3 did not participate in stress distribution. CONCLUSION: 1. The more implants supported, the less stress was induced, regardless of applied occlusal loads. 2. The maximum von Mises stress in the bone of the implant-supported three unit fixed dental prosthesis with a mesial cantilever was 1.38 times that with a central pontic. The maximum von Mises stress in the bone of the implant-supported three-unit fixed dental prosthesis with a distal cantilever was 1.59 times that with a central pontic. 3. A distal cantilever induced larger stress in the bone than a mesial cantilever. 4. A adjacent tooth which contacts implant-supported fixed prosthesis participated in the stress distribution.

• The Journal of the Korean dental association
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• v.54 no.3
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• pp.198-205
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• 2016

The purpose of this paper was to investigate the significance of splinted and non-splinted implant-supported restorations with an internal connection for multiple consecutively missing teeth. Upon examination of the effects of fixture-abutment connection, the distribution of occlusal load was favorable in splinted implant-prosthesis with an external connection, but effect of strain distribution was not significant in splinted implant-prosthesis with an internal connection. In splinted implant-prostheses for short implants, strain distribution was not affected by the method of retention. For cement-retained prostheses, the effect of strain distribution due to splinting was not significant. In clinical studies, non-splinted prostheses with an internal connection for multiple consecutively missing teeth showed high survival rate, mild marginal bone loss, and stable periodontal condition. However, failure to achieve optimal proximal contact between single-unit prostheses may lead to food impaction, and veneer fracture may be inevitable when the framework provides inadequate support in the proximal region. In conclusion, splinted implant-prosthesis is not an indication in all cases, and clinical consideration of its use should be based on the patient's oral condition, such as location and number of implants, formation of proximal contact, canine guidance, existence of parafunctional habit, and oral hygiene, when multiple consecutively missing teeth are replaced by internal connection type implant.