• The Journal of Advanced Prosthodontics
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• 제13권1호
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• pp.12-23
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• 2021

Purpose. The aim of the study was to compare the lingualized implant placement creating a buccal cantilever with prosthetic-driven implant placement exhibiting excessive crown-to-implant ratio. Materials and Methods. Based on patient's CT scan data, two finite element models were created. Both models were composed of the severely resorbed posterior mandible with first premolar and second molar and missing second premolar and first molar, a two-unit prosthesis supported by two implants. The differences were in implants position and crown-to-implant ratio; lingualized implants creating lingually overcontoured prosthesis (Model CP2) and prosthetic-driven implants creating an excessive crown-to-implant ratio (Model PD2). A screw preload of 466.4 N and a buccal occlusal load of 262 N were applied. The contacts between the implant components were set to a frictional contact with a friction coefficient of 0.3. The maximum von Mises stress and strain and maximum equivalent plastic strain were analyzed and compared, as well as volumes of the materials under specified stress and strain ranges. Results. The results revealed that the highest maximum von Mises stress in each model was 1091 MPa for CP2 and 1085 MPa for PD2. In the cortical bone, CP2 showed a lower peak stress and a similar peak strain. Besides, volume calculation confirmed that CP2 presented lower volumes undergoing stress and strain. The stresses in implant components were slightly lower in value in PD2. However, CP2 exhibited a noticeably higher plastic strain. CONCLUSION. Prosthetic-driven implant placement might biomechanically be more advantageous than bone quantity-based implant placement that creates a buccal cantilever.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제21권3호
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• pp.240-248
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• 1999

골재생유도술에 의한 골재생 과정에서의 생물학적 현상을 보다 구체적으로 이해하고자 인위적으로 골결손부를 형성하고, 비흡수성 비공유성 차폐막을 이용하여 골성회복 시 주위 연조직의 유입을 차단한 다음 골수강 및 골면으로부터 유래되는 세포들에 의한 골성회복 양상과 이때 이들 세포의 조골세포로의 분화정도를 판정하기 위하여 비교원성 골기질 단백질인 OSN, OPN 그리고 OSC mRNA의 발현 양상을 비교 검토하여 다음과 같은 결과를 얻었다. 실험 전기간에 걸쳐 골재생유도술을 시행한 군에서 보다 신속하고 양호한 골성회복을 보였다. 차폐막을 처리한 실험군에서는 인접골의 주변부로부터 신생골이 형성되어 조골세포의 분화가 조기에 골결손부에 국한되어 유도된 반면, 대조군에서는 주변연조직의 개입으로 인하여 실험군 보다는 약 1주정도 신생골의 형성이 지연되었으며, 따라서 골수강 내의 기질세포의 조골세포로의 분화 역시 지연되었다. 이상의 사실에서 골창상부에서 차폐막에 의해 형성된 차폐공간은 기질 세포들의 보다 신속한 조골세포로의 분화 증식과 이들에 의해 신생된 골주들의 빠른 골 개조를 조장하였음을 시사한다.

• Restorative Dentistry and Endodontics
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• 제36권1호
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• pp.12-18
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• 2011

목적: 본 후향적 연구의 목적은 의도적 재식술로 치료한 상하악 대구치의 단기간의 치료 결과를 평가하고자 하는 것이다. 환자 및 방법: 본 연구의 대상은 해부학적인 접근의 어려움 및 두꺼운 피질골 또는 하치조 신경, 상악동등과의 근접으로 인해 통상적인 치근단 수술이 불가능하거나 환자가 거부하는 경우 의도적 재식술을 시행한 35개의 상하악 대구치를 대상으로 하였다. 증례들의 경과 관찰 기간은 1년에서 2년 4개월이었다. 성공률은 임상적 성공과 방사선학적 성공을 기준으로 평가하였다. 결과: 의도적 재식술 과정중 발치 실패가 1증례(3%), 치주 질환 및 염증성 흡수로 발치한 경우가 2증례(6%)였고 구강내에서 기능하고 있으나 약간의 동요도와 치근의 흡수상이 관찰되는 경우가 3증례(9%)였고 특이한 이상없이 잘 유지되고 있는 경우는 29증례(82%)였다. 결론: 의도적 재식술은 접근성 및 해부학적인 구조등으로 인해 치근단 수술이 불가능한 경우 적절한 증례 선택과 숙련된 술자에 의해 시술이 이루어진다면 재현성 있고 예지성있는 치료가 될 수 있다.

• Experimental and Molecular Medicine
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• 제50권12호
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• pp.12.1-12.14
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• 2018

Osteoporosis develops with high prevalence in both postmenopausal women and hypogonadal men. Osteoporosis results in significant morbidity, but no cure has been established. Mesenchymal stem cells (MSCs) critically contribute to bone homeostasis and possess potent immunomodulatory/anti-inflammatory capability. Here, we investigated the therapeutic efficacy of using an infusion of MSCs to treat sex hormone-deficient bone loss and its underlying mechanisms. In particular, we compared the impacts of MSC cytotherapy in the two genders with the aim of examining potential gender differences. Using the gonadectomy (GNX) model, we confirmed that the osteoporotic phenotypes were substantially consistent between female and male mice. Importantly, systemic MSC transplantation (MSCT) not only rescued trabecular bone loss in GNX mice but also restored cortical bone mass and bone quality. Unexpectedly, no differences were detected between the genders. Furthermore, MSCT demonstrated an equal efficiency in rectifying the bone remodeling balance in both genders of GNX animals, as proven by the comparable recovery of bone formation and parallel normalization of bone resorption. Mechanistically, using green fluorescent protein (GFP)-based cell-tracing, we demonstrated rapid engraftment but poor inhabitation of donor MSCs in the GNX recipient bone marrow of each gender. Alternatively, MSCT uniformly reduced the $CD3^+T$-cell population and suppressed the serum levels of inflammatory cytokines in reversing female and male GNX osteoporosis, which was attributed to the ability of the MSC to induce T-cell apoptosis. Immunosuppression in the microenvironment eventually led to functional recovery of endogenous MSCs, which resulted in restored osteogenesis and normalized behavior to modulate osteoclastogenesis. Collectively, these data revealed recipient sexually monomorphic responses to MSC therapy in gonadal steroid deficiency-induced osteoporosis via immunosuppression/anti-inflammation and resident stem cell recovery.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제35권5호
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• pp.372-375
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• 2009

Central odontogenic fibroma is an extremely rare benign tumor, accounting for less than 0.1% of all odontogenic tumors. The most recent literature review that only 69 cases have so far been reported. This tumor has a slow persistent growth that results in painless cortical expansion clinically, and well defined unilocular or multilocular radiolucent lesion. Root resorption of associated teeth is common, and lesions located between the teeth often cause root divergence. There is occurring tendency to female more than male, and occurring in the mandible and in the maxilla with equal frequency. The treatment is surgical excision with no tendency to undergo malignant transformation. We report a case of central odontogenic fibroma in the maxilla of a 27-year male with literatures review.

• 치과방사선
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• 제25권1호
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• pp.159-170
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• 1995

Few cases of florid osseous dysplasia has been described as a condition that characteristically affects the jaws. It usually manifests as multiple radiopaque masses distributed throughout the jaws. Confusion exists about the relationship of florid osseous dysplasia, gigantiform cementoma, chronic sclersing osteomyelitis, sclerosing osteitis or multiple enostosis. Authors experienced a case of florid osseous dysplasia of the jaws in 52-year-old female on the basis of clinical, radiographic and histopathologic findings. The characteristic features are as follows : 1. In clinical examination, there was no clinical sign and symptoms except extracted area. And there was no facial asymmetry. 2. Radiograms show round or lobular dense radiopaque masses surrounded by radiolucent bands in lower molar teeth area bilaterally. And slight increased radiopacities in maxillary molar teeth area bilaterally. There was no expansion or thinning of buccal and lingual cortical bones. There is no displacement or resorption of involved teeth. In right side of mandible, mandibular canal is displaced inferiorly due to mass. 3. Photomicrograms show densely mineralized sclerotic acellular masses with empty lacunae. Pattern is suggestive of cementum, although it could be considered sclerotic bone. In the periphery, lesion consisting of moderately cellular fibrous tissue in which globular calcified products are deposited.

• Imaging Science in Dentistry
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• 제39권3호
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• pp.169-173
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• 2009

The calcifying odontogenic cyst (COC) is a rare disorder of the jaws and shows various radiographic features. The purpose of this study is to describe the different radiographic appearances of 2 cases of COC. Case 1 was located in the posterior maxilla extending into maxillary sinus, showing unilocular radiolucency with a well-defined margin. Cortical bone expansion and thinning were prominent. Root resorption of adjacent teeth was apparent. Case 2 showed unilocular radiolucency with a calcified material. Calcification was supposed to be dystrophic dental hard structures, detected at the periphery of the lesion. Ghost cell and proliferation of ameloblastoma-like tissues were common features for these two lesions on histopathological findings. This reports presented common and atypical radiographic features of the COC.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제36권3호
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• pp.211-213
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• 2010

Glandular odontogenic cyst (GOC) is an intraoral cyst originated from serre remnants which has incidence of rare frequency. Only 111 cases have been reported since Gardener first introduced it in 1987. The clinical features are the following components: cortical bone thinning, locally aggressive root resorption, non-painful swelling. The following recurrences rate are 64.3% in conservative treatment, and 0% in wide excision for instance, segmental or marginal mandibulectomy. So, its prognosis is similar to that of odontogenic keratocyst and ameloblastoma. Therefore, periodic recall follow ups are essential to detect disease recurrence. Here, we will report the first case of GOC diagnosed in our department considering with references. And we share this treatment experience because these aggessive lesions may be misjudged for simple dental cyst.

• Imaging Science in Dentistry
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• 제32권3호
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• pp.167-173
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• 2002

Purpose : To evaluate clinical and radiographic differential diagnosis between ameloblastoma and odontogenic keratocyst (OKC) using clinical data, plain radiographs, and CT. Materials and Methods: 25 cases of ameloblastoma and 44 cases of OKC diagnosed in biopsy, were selected from the files stored in Department of Oral and Maxillofacial Radiology, Seoul National University Dental Hospital from 1999 to 2001, and evaluated using following criteria: sex and age, location, shape, border to normal bone tissue, effect to adjacent tissues, homogeneity in the lumen of the lesion, response of the cortical bone, long-to-short length (LIS) ratio of the lesion, and expansion angle of the cortex. Results: Ameloblastoma and OKC were seen most frequently in third decades and no statistical significance was noted between both sexes. Ameloblastoma occurred most frequently in mandibular angle and ramus area (68%) and OKC at the maxillary molar (34.1 %), and mandibular angle and ramus area (43.2%). The root resorption of the adjacent teeth, mandibular canal displacement, and the impaction of teeth were seen more frequently in ameloblastoma than in OKC. The LIS ratio measured in CT was largest in maxillary OKC cases, followed by mandibular ameloblastoma, and mandibular OKC (1.2, 1.8 and 2.4 respectively). The expansion angle of the cortex shows a statistically significant difference between ameloblastoma (48.8°) and OKC (31.5°). Conclusion : The numeric morphology (LIS ratio) and expansion angle of the cortical bone of the lesion measured in computed tomography can be used to differentiate the ameloblastoma and odontogenic keratocyst.

• 대한정형외과학회지
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• 제55권6호
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• pp.503-510
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• 2020

목적: 고령의 환자에게 발생한 대퇴골 전자간 불안정성 골절에 대하여 관혈적 정복 및 내고정 이외의 다른 대안으로 고관절 반치환술이 선택적으로 사용되고 있다. 최근 의료 시스템과 기술의 발달로 대퇴골 전자간 골절 후 생존율이 높아지면서 중장기 이상의 기간을 고려한 대퇴 스템의 선택이 필요하다. 이에 저자들은 이중으로 가늘어 지는 직각 단면의 대퇴 스템(C2 stem)을 이용하여 불안정성 전자간 골절에 고관절 반치환술을 시행하고 5년 이상 추시한 환자에 대하여 그 임상적 방사선적 결과를 알아보고자 하였다. 대상 및 방법: 2004년 1월부터 2013년 12월까지 대퇴골 전자간 불안정성 골절에 대하여 C2 스템으로 고관절 반치환술을 시행한 43명의 환자(43 고관절)를 대상으로 하였다. 평균 연령은 78.6세(70-84세), 평균 추시 기간은 85.4개월(60-96개월)이었다. 추시 기간 동안 임상적으로는 통증, 보행 능력, 고관절 기능의 변화를 알아보았고, 방사선적으로는 피질골의 골다공증과 골 흡수 등 근위 대퇴골의 변화를 알아보았으며, 탈구와 인공 관절 주변 골절 등 추시 기간 중 발생한 합병증에 대하여 알아보았다. 결과: 통증은 수술 후 유의하게 감소하였는데, 수술 후 4년부터 증가하였고 수술 후 60개월에 보행 능력 평가에서 9예의 환자가 두 단계 보행 능력이 감소하였으며 Harris 고관절 점수는 수술 후 2년부터 3년 사이에 유의하게 감소하였다. 방사선적으로 피질골 골다공증은 14예 발생하였는데, 이 중 5예의 환자가 피질골 흡수 현상으로 진행하였다. 피질골 흡수 현상을 보인 5예 중 4예는 전자부 골절편이 불유합 된 경우였고, 3예는 역사상 골절인 경우였다. 결론: 골다공증을 동반한 고령의 환자에게 발생한 불안정성 전자간 골절에 3C 형태의 무시멘트 스템을 이용하여 고관절 반치환술을 일차로 시행하는 경우 환자의 건강 상태와 잔여 수명을 고려하여 주의 깊은 선택이 필요할 것으로 생각된다.