• Maxillofacial Plastic and Reconstructive Surgery
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• 제20권4호
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• pp.275-278
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• 1998

Recently, the clinical applications of the autogenous cancellous bone from the proximal tibial metaphysis show satisfactory results in the repair of maxillofacial bony defect or deformity. The proximal tibia has the potential to yield viable cancellous bone with a minimum of morbidity. The purpose of this study was to investigate the regeneration of a full thickness proximal tibial bone defect with covering or uncovering of cortical bone. The follow-up periods were 4, 8, and 12 weeks. Bone defect of right side was uncovered and left side was covered with cortical bone. In the experimental group (uncovered cortical bone) at 12 weeks, the inside of defect was filled to normal marrow tissue. The cortical bone defect was united of inner, outer callus at 4, 8 weeks in both study group. At 12 weeks, the cortical bone defect was remodeled and invaded by osteoclast (giant cell) in experimental group. In the experimental specimen at 12 weeks, the regenerating tissue of bone defect was not differ from the control group.

• 한국정밀공학회지
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• 제19권4호
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• pp.18-24
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• 2002

• Restorative Dentistry and Endodontics
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• 제20권1호
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• pp.17-32
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• 1995

The purpose of this study was to examine the response of periradicular tissues to amalgam, IRM, Ketac-silver and MTA(Mineral trioxide aggregate) used as a root end fillings. The lower third and fourth premolars of 5 mongrel dogs were used. Each root was resected, followed by root end fillings with experimental materials. The animals were sacrificed after 16 weeks and radiographic and histologic results were evaluated. The results were as follows : 1. Severe inflammation around apex and disruption of cortical were noted in relation to the amalgam. 2. With IRM, there was severe infiltration of inflammatory cells around filling material, but healing of cortical bone was noted. 3. With Ketac-silver, mild inflammation and thick band of fibrous connetive tissue around filling material were seen, with a cortical bone healing. 4. In case of MTA, complete regeneration of cortical bone was seen, and free MTA was surrounded with newly formed bone tissue.

• 대한치과보철학회지
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• 제34권1호
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• pp.187-200
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• 1996

After loss of tooth, initial healing process is critical to preserve residual alveolar process. This study was conducted to compare the effect of hydroxylapatite particle synthetic graft and guided tissue regeneration procedure on healing of extraction wounds in 5 mongrel dogs. To investigate the maturity of bone and velocity of bone heating, bone-labeled tracers were used. After 16 weeks healing period, dogs were sacrificed. The specimens were treated with Villanueva bone stain. Fluorescence microscopy and polarized microscopy were performed to exam the pattern of bone formation in the extraction socket. The results were following ; 1. Pattern of bone regeneration in the group of hydroxylapatie graft and the group of membrane protection after hydroxylapatite graft was following ; bone regeneration was slow, regenerated bone was immature, and thickness of cortical layer was thin compare to that of untreated control group. 2. Cortical layers in membrane protected group were somewhat thicker but less condense to that of untreated control group. 3. Infiltration of inflammation cells were found in the groups using hydroxylapatite graft and membrane. We concluded that grafting of replamineform hydroxylapatite particles into the extraction socket delayed healing of the wound and disturbed the formation of cortical bone at the roof of extraction socket. The placement of expanded polytetrafluoroethylene membranes on the extraction socket promotes the bone regeneration. But newly formed bone in cortical layer consists of the cortico-cancellous bone in comparison with the cortical bone of the control group.

• 대한치과교정학회지
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• 제37권3호
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• pp.212-219
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• 2007

현재 교정용 미니 임플란트의 식립부위에 대한 연구는 주로 구치부 치근사이 공간에 집중되어 왔으며, 연조직에 관한 연구는 부족하다. 본 연구의 목적은 하악골에서 전치부와 구치부의 치근사이 피질골과 연조직 두께를 측정하여 해부학적인 지도를 만들고, 한국인의 평균 부착치은의 폭경을 제시하는데 있다. 연구를 위하여 자원한 남자 15명, 여자 15명 총 30명을 대상으로 하였으며, 평균연령은 27세 3개월이었다. 구강 내 인상을 채득한 후 석고모형을 만들어 0.5 mm두께의 평판으로 스텐트를 제작하였다. 스텐트의 중절치에서 제1대구치까지 치근사이 치은변연을 연결한 선에 방사선 불투과성의 표식을 부착하고 구강 내에 장착한 후 3차원 CT 영상을 얻고, 각 치근사이 치조정 하방에서 2, 4, 6, 8 mm부위의 피질골 두께를 측정하였다. 연조직 두께는 스텐트의 각 치근사이 치조정 하방에서 2, 4, 6, 8 mm부위에 구멍을 뚫고 구강 내에서 근관치료용 파일을 연조직에 통과시켜 측정하였다. 석고모형 상에서 중절치에서 제1대구치까지 각 치근중앙 부위에서 부착치은의 폭경을 측정하였다. 연구결과 하악골에서 전체대상자의 평균 피질골 두께는 $1.33{\pm}0.38mm$이었으며 전치부에서 구치부로 갈수록 두꺼워지고, 평균 연조직 두께는 $1.49{\pm}0.54mm$이었으며 치근단 쪽으로 내려가면서 두께가 변하지 않았다. 평균 전체 두께는 $2.82{\pm}0.70mm$이었으며 전치부에서 구치부로 갈수록 두꺼워졌다. 부착치은의 폭경은 전치부가 구치부보다 넓었다. 이상의 결과는 피질골과 연조직 두께, 부착치은의 폭경을 고려하여 미니 임플란트의 식립부위를 결정하는 것이 필요함을 시사하였다.

• Journal of Veterinary Science
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• 제24권6호
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• pp.79.1-79.16
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• 2023

Background: The need for a storage method capable of preserving the intrinsic properties of bones without using toxic substances has always been raised. Supercooling is a relatively recently introduced preservation method that meets this need. Supercooling refers to the phenomenon of liquid in which the temperature drops below its freezing point without solidifying or crystallizing. Objectives: The purpose of this study was to identify the preservation efficiency and applicability of the supercooling technique as a cortical bone allograft storage modality. Methods: The biomechanical effects of various storage methods, including deep freezing, cryopreservation, lyophilization, glycerol preservation, and supercooling, were evaluated with the three-point banding test, axial compression test, and electron microscopy. Additionally, cortical bone allografts were applied to the radial bone defect in New Zealand White rabbits to determine the biological effects. The degree of bone union was assessed with postoperative clinical signs, radiography, micro-computed tomography, and biomechanical analysis. Results: The biomechanical properties of cortical bone grafts preserved using glycerol and supercooling method were found to be comparable to those of normal bone while also significantly stronger than deep-frozen, cryopreserved, and lyophilized bone grafts. Preclinical research performed in rabbit radial defect models revealed that supercooled and glycerol-preserved bone allografts exhibited significantly better bone union than other groups. Conclusions: Considering the biomechanical and biological superiority, the supercooling technique could be one of the optimal preservation methods for cortical bone allografts. This study will form the basis for a novel application of supercooling as a bone material preservation technique.

• Restorative Dentistry and Endodontics
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• 제41권4호
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• pp.310-315
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• 2016

Two case reports describing a new technique of creating a repositionable piezoelectric bony window osteotomy during apicoectomy in order to preserve bone and act as an autologous graft for the surgical site are described. Endodontic microsurgery of anterior teeth with an intact cortical plate and large periapical lesion generally involves removal of a significant amount of healthy bone in order to enucleate the diseased tissue and manage root ends. In the reported cases, apicoectomy was performed on the lateral incisors of two patients. A piezoelectric device was used to create and elevate a bony window at the surgical site, instead of drilling and destroying bone while making an osteotomy with conventional burs. Routine microsurgical procedures - lesion enucleation, root-end resection, and filling - were carried out through this window preparation. The bony window was repositioned to the original site and the soft tissue sutured. The cases were re-evaluated clinically and radiographically after a period of 12 - 24 months. At follow-up, radiographic healing was observed. No additional grafting material was needed despite the extent of the lesions. The indication for this procedure is when teeth present with an intact or near-intact buccal cortical plate and a large apical lesion to preserve the bone and use it as an autologous graft.

• 대한치과보철학회지
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• 제30권4호
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• pp.526-540
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• 1992

Osteoporosis, a well known metabolic bone disease, occurs due to imbalance of bone formings and resorptions. In an attempt investigate if postmenopausal osteoporosis would have influence on the mandible, histomorphometric analysis was performed in the mandible and the femur of the albino rats. Osteoporosis was induced by bilateral oophorectomy. To determine the effect of calcitonin, calcitonin(Asahi Chemical Co., Japan) was injected in the oophorectomized rats. The results were as follows : 1. The width of cortical bone of the femur was decreased in the oophorectomized group compared to the normal control and calcitonin injected groups and the porosity of cortical bone of the femur was increased in the oophorectomized group compared to the normal control and calcitonin injected groups. 2. The osteoid tissue and resorption lacuna of the femur was increased in both oophorectormized and calcitonin injected groups than the normal control group. 3. The width of cortical bone of the mandible was decreased in the oophorectomized group compared to the normal control and calcitonin injected groups. 4. The porosity of cortical bone of the mandible was decreased in both oophorectomized and calcitonin injected groups than the normal control group. 5. The relative volume of trabecular bone of the mandible was decreased in the oophorectomized group compared to the normal control and calcitonin injected groups. 6. The osteoid tissue of the mandible was increased in the calcitonin injected group than the normal control and oophorectomized groups. 7. The resorption lacuna of the mandible was increased in both oophorectomized and calcitonin injected groups, particularly in the oophorectomized group.

• 한국임상수의학회지
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• 제17권1호
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• pp.76-82
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• 2000

This study was undertaken to find out the effect of persimmon leaves on histopathological changes of cadmium toxicity in mice. Seventy two BALB/c mice of male were divided into a control group(A) and five experimental groups (B, C, D, E, F) : group A received tap water and basal diet, group B received tap water and diet supplemented with 3% persimmon leaves alone, group C received basal diet and 300 ppm cadmium, group D, E and F received basal diet supplemented with 1, 3% and 7% persimmon leaves and 300 ppm cadmium respectively. Cadmium dissolved in tap water was used, and the persimmon leaves were mixed with feed. All mice were dissected on the 84th day. Pathological changes in liver, kidney, cortical osseous tissue of femoral shaft, bone trabecular of femur, and epiphyseal cartilage plate of femur were observed. Group B showed no significant changes as the control group. But group C showed the unclearness of specific cells in liver, the loss of architecture and necrosis of hepatocyte, degeneration and necrosis of renal convoluted tubules, desquamation and vacuolization of the greater part of the renal tubular epithelium, marked thinning of the cortical osseous tissue in femoral shaft, reduction of cancellous bone volume and decreaswe of trabecular number, and marked thinning of epiphyseal cartilage plate in femur. On the other hand, persimmon leaves-treated group showed a little convalescent changes an maintained their normal architectures in liver, kidney, cortical osseous tissue of femoral shaft, bone trabecular of femur, and epiphyseal cartilage plate of femur.

• Advances in biomechanics and applications
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• 제1권1호
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• pp.15-22
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• 2014

Computed tomography (CT) is being utilized in orthopaedics and related research to estimate bone strength. These applications benefit from calibration of Hounsfield units to mineral density typical of long bone, up to $1750mg/cm^3$. This study describes a method for establishing repeatable calibration of Hounsfield units to density, and determines the effects of imaging medium on calibration accuracy. Four hydroxyapatite standards were imaged in air on 7 occasions over 19 weeks using a helical multi-slice CT scanner. Each standard was scanned 5 times in different media: porcine soft tissue, water, and air. Calibrated densities were highly repeatable (CV<3.5%). No difference in density was observed between water and soft tissue conditions (p>0.08). This work provides a model for determining repeatable scanner-specific density calibration, demonstrates that the linear relationship between Hounsfield units and density extends to values typical of cortical bone, and supports the practice of imaging calibration standards in an environment similar to that of the target bone.