• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.15 no.3
• /
• pp.102-108
• /
• 2016

A dental ultrasonic surgical instrument, commercially known as a scaler, is a high-value-added advanced technology that is used for tartar removal, implant operations, and gum and jaw bone surgery. In this study, the piezoelectric phenomenon for making linear motion associated with input electrical signals was studied, and the behavior of the ultrasonic vibrator was investigated by using the commercially available finite element program ANSYS(R) for the purpose of designing dental surgery tools. Modal analysis was carried out, and the optimal frequency range was calculated from the analyzed results. The ultrasonic vibrator was then redesigned based on the calculated optimal frequency range. The performance of the system was tested, and consequently, the proposed methodology was proven useful in vibrator design.

• The Journal of the Korean dental association
• /
• v.10 no.1
• /
• pp.47-50
• /
• 1972

저자는 18세부터 24세의 남녀 5명의 치근단병소가 있는 전치에 iodoform paste로 근관과잉충전을 한후 X-선상으로 그 흡수 현상을 관찰 하였던 바 다음과 같은 결론은 얻었다. 1) 비록 동종의 근관충전용 호제(paste)로 근관충전치료를 하였어도 각치아에서의 흡수율에는 큰 차이가 있었다. 2) 요도포름호제의 흡수율은 3,4주에서 보다 1,2주에서 더 빠르게 나타났다. 3) 치근관내에서의 흡수율은 상당히 느렸으며 2주후에 흡수가 나타난 예도 있었다. 4) 치료후 4주간에서는 확산성, 침윤성, 침윤성증상이 X-선상에 나타났으나 3개월후에는 뚜렷한 경계를 가진 병소부를 볼 수 있었으며, 치조골구조의 변화는 병소부의 주위에 신생골의 정밀한 증식으로 연속적인 백선이 형성된 것을 볼 수 있었다.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.28 no.7
• /
• pp.940-947
• /
• 2004

In this paper, an optimum design problem for endosseous implant in dentistry is studied to find best implant design. An optimum design problem is formulated to reduce stresses arising at the cortical as well as cancellous bones, in which sufficient design parameters are chosen for design definition that encompasses major implants in popular use. Optimization at once (OAO) with the large number of design variables, however, causes too costly solution or even failure to converge. A concept of multilevel optimization (MLO) is employed to this end, which is to group the design variables of similar nature, solve the sub-problem of smaller size for each group in sequence, and this is iterated until convergence. Each sub-problem is solved based on the response surface method (RSM) due to its efficiency for small sized problem.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2008.04a
• /
• pp.613-617
• /
• 2008

One of the important parts on multimedia era is acoustic ones. With increased demand of smallest multimedia products such as personal digital assistant (PDA) and mobile phones, it is necessary to develop acoustic devices which have higher performance and smaller size. Acoustic parts with various function for hearing impaired persons. This paper introduces a bone conduction vibrator (BCV) for hearing impaired persons to use portable acoustic device without additional devices. For vibration analysis of the BCV, electromagnetic, mechanical and their coupling effects are considered for the analysis. This paper shows that the development of design and analysis technique by finite element method (FEM) of BCV.

• Proceedings of the KAIS Fall Conference
• /
• 2002.05a
• /
• pp.176-179
• /
• 2002

발의 구조는 사람에 따라 약간의 차이를 보이기는 하나 일반적으로 중앙을 기준으로 할 때 비대칭적(Asymmetric)인 구조를 보인다. 특히 동양인의 경우, 비대칭성에 의한 발의 좌우 편차는 서양인에 비해 큰 것으로 알려져 있다. 따라서 발 길이 뿐만 아니라 발 둘레, 발 높이, 볼 거스(Ball girth) 등을 고려할 경우 발의 형태는 더욱 다양해지며, 이를 고려한 족형의 개발은 신발 설계에 있어서 필수적으로 요구된다 하겠다. 이 논문은 전국 남녀 8000명의 좌, 우 발의 각 25개 부위 측정한 후 전문가들의 조언을 통해 가장 구두골 제작에 영향을 주리라 생각되는 발의 10개 중요 부위를 이용하여 현재 단순히 유아용, 아동용, 학생용, 성인용으로 구분되어진 구두치수를 Classification 기법을 사용하여 연령별로 적절하게 구분되어 구두를 개발할 수 있도록 하였다.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
• /
• v.22 no.1
• /
• pp.77-84
• /
• 1992

The purpose of this study was to evaluate the diagnostic value of panoramic radiography for diagnosis of temporomandibular joint. Five dry skulls were selected for this study and artificial osteophyte was attached to four different areas of the mandibular condylar head. And then, the author had taken panoramic radiographs with the head in conventional position, 25㎜ forward position and reverse position in mouth opening state. Three dental radiologists evaluated the radiographic images of osteophyte in 60 panoramic radiographs. The results were as follows: In conventional position, osteophyte on the anterolateral and anterocentral area of the condylar head was best seen (p<0.01). In 25㎜ forward position, osteophyte on the anterocentral and anteromedial area was best seen (p<0.05). In reverse position, osteophyte on the anterocentral area was best seen (p<0.05). Osteophyte on anteromedial area was better seen in 25㎜ forward position than in conventional position (p<0.05).

• The Journal of the Korean bone and joint tumor society
• /
• v.10 no.2
• /
• pp.120-123
• /
• 2004

Benign and malignant bone tumors occur most commonly around the knee. The proximal tibia is the most technically demanding site for limb salvage surgery. The most difficult problem using an endoprothesis for proximal tibial resection has been reconstruction of the extensor mechanism. After excision of proximal tibia, we resected distal femur and made a composite with resected distal femur, low heat treated autogenous proximal tibia and endoprothesis. Patella was fixed into the resected down-loaded distal femur. This article shows the new technique and the results of reconstruction of extensor mechanism after prosthetic replacement of the proximal tibia.

• The Journal of the Korean bone and joint tumor society
• /
• v.20 no.1
• /
• pp.32-35
• /
• 2014

Rosai-Dorfman disease (RDD) is an idiopathic histioproliferative disorder of lymph node and extranodal site. Bone involvement is very rare. We report a case of extranodal RDD of the tibia in 32-year old male. The patient presented with pain with no evidence of lymphadenopathy. Clinico-radiologic diagnosis was metastatic carcinoma or Langerhans cell histiocytosis, but, histopathologic examination confirmed the diagnosis with RDD. We performed curettage on the osteolytic lesion of tibia. In South Korea, there was no report about RDD of the extremity and we want to report this case with review of the literature.

• Journal of the Korean Society for Precision Engineering
• /
• v.24 no.1 s.190
• /
• pp.110-117
• /
• 2007

This study investigated changes of mechanical characteristics of the trabecular and cortical bone in the lumbar vertebrae of the ovariectomised (OVX) rat. In previous researches, there were many studies for morphology of osteoporotic bones based on Micro-Computed Tomography (Micro-CT). However, there were few studies for detecting and tracking changes of mechanical characteristics of the trabecular and cortical bone in the lumbar vertebrae of the OVX rat. For this study, the 4th lumbar of the OVX rat (female Sprague-Dawley) was utilized as a specimen. An OVX rat was scanned at week 0 (just before surgery), at week 4, and week 8 after surgery. Micro-finite element (${\mu}-FE$) analysis was used to investigate mechanical characteristics of the trabecular and cortical bone in the lumbar vertebrae for an OVX rat. When the OVX rat (at week 8) was compared with the OVX rat (at week 0), the structural modulus of cortical and trabecualr bone was decreased by 52% and 99%, respectively. This study showed the change of mechanical characteristics of cortical bone as well as trabecular bone of an OVX rat. Detecting and tracking changes of mechanical characteristics could greatly contribute to an experiment test for the trabecular and cortical bone in the lumbar vertebrae of an OVX rat by using In-vivo Micro-CT.

• Journal of the Korean Arthroscopy Society
• /
• v.14 no.2
• /
• pp.131-134
• /
• 2010

Inappropriate treatment of osteochondral fracture can cause osteoarthritis, pain, functional disorder. With large osteochondral fracture, reduction and fixation of the fragment using metal implant. However, when the bone fragment had less than 2mm, the fragment extracted because of difficulty of fragment fixation. Authors treated patients with fracture fragment thickness less than 2mm of osteochondral dissecans in medial femoral condyle and patella fracture using biodegradable meniscus screw, and then we obtained good result.