• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1997년도 춘계학술대회
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• pp.374-378
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• 1997

Operative procedures such as core drilling with and without fibular bone grafting have been recognized as the treatment methods for osteonecrosis of femoral head(ONFH) by delaying or preventing the collapse of the femoral head. In addition, core drilling with cementation using polymethylmethacrylate (PMMA) has been proposed recently as another surgical method. However, no definite treatment modality has been found yet while operative procedures remain controversial to many clinicians In this study, a finite element method(FEM) was employed to analyze and compare various surgical procedures of ONFH to provide a biomechanical insight. This study was based upon biomechanical findings which suggest stress concentration within the femoral head may facilitate the progression of the necrosis and eventual collapse. For this purpose, five anatomically relevant hip models were constructed in three dimensions : they were (1) intact(Type I), (2) necrotic(Type II), (3) core drilled only(Type III), (4) core drilled with fibular bone graft(Type IV), and (5) core drilled with cementation(Type V). Physiologically relevant loading were simulated. Resulting stresses were calculated. Our results showed that the volumetric percentage subjected to high stress in the necrotic cancellous region was greatest in the core drilled only model(Type III), followed by the necrotic(Type II), the bone graft (Type IV), and the cemented(Type V) models. Von Mises stresses at the tip of the graft(Type IV) was found to be twice more than those of cemented core(Type V) indicating the likelihood of the implant failure. In addition, stresses within the cemented core(Type V) were more evenly distributed and relatively lower than within the fibular bone graft(Type IV). In conclusion, our biomechanical analyses have demonstrated that the bone graft method(Type IV) and the cementation method(Type V) are both superior to the core decompression method(Type III) by reducing the high stress regions within the necrotic cancellous bone. Also it was found that the core region filled with PMMA(Type V) provides far smoother transfer of physiological load without causing the concentration of malignant stresses which may lead to the failure than with the fibular bone graft(Type IV). Therefore, considering the above results along with the degree of difficulties and risk of infection involved with preparation of the fibular bone graft, the cementation method appears to be a promising surgical treatment for the early stage of osteonecrosis of the femoral head.

• 대한치과보철학회지
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• 제53권1호
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• pp.81-85
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• 2015

본 증례의 환자는 상악 전치부 보철물의 파절 및 기존에 사용하던 하악 의치의 불편감 때문에 임플란트를 이용한 고정성 보철을 원한다는 주소로 내원하였다. 상악동 거상술, 하악지 골이식과 함께 상악에 5개, 하악에 6개의 임플란트를 식립하였다. 전치부와 양쪽 구치부의 세 부분으로 나누어 임플란트 지지형 고정성 보철물을 장착하였다. 이상과 같은 과정을 통해 적절한 심미적, 기능적 결과를 얻었기에 이를 보고하고자 한다.

• 구강회복응용과학지
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• 제29권4호
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• pp.399-406
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• 2013

자연치아와 연결한 임플란트 수복물에서 종종 자연치아의 압하가 보고되곤 하지만 임플란트에 둘러싸인 자연치아의 압하에 대한 보고는 매우 드물다. 56세의 여성을 하악 우측 제1소구치는 임플란트로, 제 2소구치 치근은 포스트 수복 후 지르코니아로 각각 수복했다. 제 1대구치와 제 2대구치는 이미 임플란트로 수복되어 있었다. 기능 4개월 후 제 2소구치의 압하로 인한 대합치와의 간격이 분명히 관찰되었으나 불편감을 비롯한 이상증상은 없었다. 예후에 대한 자세한 설명 후 별다른 조치 없이 경과 관찰을 시작하였다. 3개월 후 치근단 방사선 사진상에서 원위치로의 치아 회복 시작이 관찰되었으며 다시 11개월이 경과한 후 치아의 추가 정출로 교합의 완전한 회복이 이루어졌다. 압하를 인지한지 2년 3개월째 관찰 중이다. 임플란트에 둘러싸인 자연치가 압하되고 저절로 회복되는 과정의 관찰을 통해 압하가 생기는 원인과 저절로 회복된 기전을 추정할 수 있었다.

• Journal of Periodontal and Implant Science
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• 제50권6호
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• pp.418-434
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• 2020

Purpose: The purpose of the present study was to evaluate the effect of silica-calcium phosphate composite (SCPC) granules on bone regeneration in extraction sockets. Methods: Ten patients were selected for a split-model study. In each patient, bone healing in SCPC-grafted and control ungrafted sockets was analyzed through clinical, radiographic, histomorphometric, and immunohistochemical assessments 6 months postoperatively. Results: A radiographic assessment using cone-beam computed tomography showed minimal ridge dimension changes in SCPC-grafted sockets, with 0.39 mm and 1.79 mm decreases in height and width, respectively. Core bone biopsy samples were obtained 6 months post-extraction during implant placement and analyzed. The average percent areas occupied by mature bone, woven bone, and remnant particles in the SCPC-grafted sockets were 41.3%±12%, 20.1%±9.5%, and 5.3%±4.4%, respectively. The percent areas of mature bone and woven bone formed in the control ungrafted sockets at the same time point were 31%±14% and 24.1%±9.4%, respectively. Histochemical and immunohistochemical analyses showed dense mineralized bundles of type I collagen with high osteopontin expression intensity in the grafted sockets. The newly formed bone was well vascularized, with numerous active osteoblasts, Haversian systems, and osteocytes indicating maturation. In contrast, the new bone in the control ungrafted sockets was immature, rich in type III collagen, and had a low osteocyte density. Conclusions: The resorption of SCPC granules in 6 months was coordinated with better new bone formation than was observed in untreated sockets. SCPC is a resorbable bone graft material that enhances bone formation and maturation through its stimulatory effect on bone cell function.

• 구강회복응용과학지
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• 제16권3호
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• pp.197-210
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• 2000

Surface roughness is one of implant surface topography and it's found that surface roughness characterizations, such as surface energy, oxide layer thickness and its chemical composition, are closely correlated if the roughness is changed. Several studies showed the importance of analyzing surface structure so the surface structure of thread implant was analyzed to measure the implant quality exactly. In this study, surface roughness of 4 implants - MK $II^{(R)}$(Nobel Biocare), $RBM^{(R)}$(Life-Core, USA), $Osseotite^{(R)}$(3i, USA), $TPS^{(R)}$(Life-Core, USA) - were measured using $Accura^{(R)}$ and 40 implants were installed into 4 sets of ten bovine ribs based on the parameters from the measurements. From this test, the following conclusions for the initial stability were drawn by measuring and comparing RFA, Periotest Value (PTV), Removal Torgue Value (RTV). 1. $R_a$ value in surface roughness measurement was increasing by the order of $MKII^{(R)}$, $Osseotite^{(R)}$, $RBM^{(R)}$, $TPS^{(R)}$ and $R_q$ value was the same order. 2. $R_q$ value in each section was observed to increase by the order of $MKII^{(R)}$, $Osseotite^{(R)}$, $RBM^{(R)}$, $TPS^{(R)}$ in top and $MKII^{(R)}$, $RBM^{(R)}$, $Osseotite^{(R)}$, $TPS^{(R)}$ in mid-section but the value of $MKII^{(R)}$ bottom was the lowest, followed by $Osseotite^{(R)}$, $RBM^{(R)}$ and $TPS^{(R)}$. 3. RFA increased by the order of $RBM^{(R)}$(7042Hz), $MKII^{(R)}$(7047Hz), $Osseotite^{(R)}$(7076Hz), $TPS^{(R)}$(7168Hz) and there was no significance between each group. 4. PTV was increasing by the order of $MKII^{(R)}$(-1.62), $TPS^{(R)}$(-1.92), $Osseotite^{(R)}$ & $RBM^{(R)}$(-2.08) and there was no significance, either. 5. Removal torque in RTV measurement showed the increasing order of $MKII^{(R)}(5.31kgf{\cdot}cm)$, $Oeeotite^{(R)}(5.71kgf{\cdot}cm)$, $TPS^{(R)}(5.92kgf{\cdot}cm)$ and $RBM^{(R)}(7.24kgf{\cdot}cm)$ and there was no significance among groups. Above observations explains that surface roughness does not make any impact on the initial stability of implants installation.

• 구강회복응용과학지
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• 제35권1호
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• pp.11-19
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• 2019

목적: 치과 임플란트 캐드 소프트웨어를 사용해 본 경험자와 무경험자에 의한 두 종류 캐드 소프트웨어의 사용자 편의성 및 만족도를 평가하는 것이다. 연구 재료 및 방법: 치과 임플란트 캐드 소프트웨어에 경험이 있는 20명의 치기공사와 캐드 소프트웨어를 사용해보지 않은 12명의 경북대학교 치과대학 학생에게 두 종류의 캐드 소프트웨어(ExoCad, Deltanine)를 이용하여 임플란트 맞춤 지대주(implant custom abutment)를 디자인하도록 하였다. 그리고 구조화된 설문지(1단계: 기본 정보 및 파일 불러오기, 2단계: 지대주 디자인 전 조건 설정, 3단계: 지대주 디자인 설정, 4단계: 전체적인 만족도)를 작성하도록 하였다. 수집된 자료의 통계분석은 Mann-Whitney U test를 사용하였다(${\alpha}=.05$). 결과: 4단계로 나누어 진 21개 문항에 대해 평가된 치과 임플란트 캐드 소프트웨어의 디자인 편의성과 만족도는 1단계의 두 문항에서 모두 Exocad 소프트웨어에서 유의하게 높았습니다. 2단계 및 3단계의 경우 경험이 있는 참가자는 Deltanine 소프트웨어가 훨씬 뛰어나다고 평가했습니다. 4단계에서는 두 문항 모두 Exocad 소프트웨어에서 높은 평가를 받았습니다. 결론: 2 종류 치과 임플란트 캐드 소프트웨어의 편의성 및 만족도 조사에서 Exocad 소프트웨어가 전체적으로 높은 평가를 받았다. 하지만 디자인 과정 중 핵심인 2, 3단계에서 유경험자는 Deltanine 소프트웨어를 높게 평가하였다. 따라서 그외 부분을 보강하면 Deltanine 소프트웨어는 임상에서 널리 사용될 수 있을 것이다.

• Journal of Periodontal and Implant Science
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• 제25권1호
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• pp.111-120
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• 1995

This case report presents two maxillary anterior cases for clinical crown lengthening by forced eruption. In the first case, clinical crown of maxillary right lateral incisor was almost lost by fracture. Forced eruption using intracoronal splint and elastic thread accomplished vertical root movement successfully. Then, post & core was inserted and final restoration was harmonious with adjacent teeth. In the second case, the crown portion of maxillary right central incisor was almost mutilated by secondary caries. Forced eruption using removable Hawley appliance and elastic accomplished vertical root movement successfully. Then, post & core was inserted and final restoration was placed. In conclusion, clinical crown lengthening by vertical root movement can be accomplished by a simple appliance without any sacrifice of periodontal support in selected patients. A clinical crown so created can be restored to adequate function and arch integrity without compromising adjacent teeth. Therefore, forced eruption is preferred in the anterior region of the dentition where esthetics is of major concern.

• Imaging Science in Dentistry
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• 제44권2호
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• pp.155-160
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• 2014

Purpose: The purposes of this study were to develop a workstation computer that allowed intraoperative touchless control of diagnostic and surgical images by a surgeon, and to report the preliminary experience with the use of the system in a series of cases in which dental surgery was performed. Materials and Methods: A custom workstation with a new motion sensing input device (Leap Motion) was set up in order to use a natural user interface (NUI) to manipulate the imaging software by hand gestures. The system allowed intraoperative touchless control of the surgical images. Results: For the first time in the literature, an NUI system was used for a pilot study during 11 dental surgery procedures including tooth extractions, dental implant placements, and guided bone regeneration. No complications were reported. The system performed very well and was very useful. Conclusion: The proposed system fulfilled the objective of providing touchless access and control of the system of images and a three-dimensional surgical plan, thus allowing the maintenance of sterile conditions. The interaction between surgical staff, under sterile conditions, and computer equipment has been a key issue. The solution with an NUI with touchless control of the images seems to be closer to an ideal. The cost of the sensor system is quite low; this could facilitate its incorporation into the practice of routine dental surgery. This technology has enormous potential in dental surgery and other healthcare specialties.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제37권
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• pp.41.1-41.6
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• 2015

Cleidocranial dysplasia is an autosomal dominant heritable skeletal disorder. The characteristic features of cleidocranial dysplasia (CCD) may include hypoplasia of the clavicle, delayed closure of frontanelles, late tooth eruption, and other skeletal disorders. This case report describes clinical and radiographic manifestations at the age of 11 and 29 of a CCD patient, investigates the mutation of core-binding factor A1 (CBFA1) based on gene analysis, and illustrates successful oral reconstruction with fixed prosthesis and dental implant after the extraction of multiple teeth.

• 대한치과의사협회지
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• 제51권1호
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• pp.6-11
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• 2013

Dental ceramics is well known to have excellent esthetics, biocompatibility as well as high compressive strength. However, the fragility of ceramics against tensile and shear loads leading to the delayed fracture of micro crack on ceramic surface and the backwardness of ceramic fabrication technique limit the usage of ceramic materials in dentistry. Among all ceramic materials, zirconia has been introduced to overcome the drawback of conventional dental ceramics in the field of dentistry due to the nature of zirconia featuring proper opalescence and high fracture toughness. Also, novel manufacturing techniques enable ceramic materials to prepare high esthetic anterior and posterior all ceramic system. In this paper, it is introduced and discussed that novel techniques characterizing the bond strength between zirconia core and veneering ceramics and analyzing the fluorescence of dental ceramics in order to overcome the gap between the results of basic research and the feasibility of the results in the field of dental clinics.