• Journal of Periodontal and Implant Science
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• 제33권4호
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• pp.673-691
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• 2003

The current interest in periodontal tissue regeneration has lead to research in bone graft, root surface treatments, guided-tissue regeneration, and the administration of growth factors as possible means of regenerating lost periodontal tissue. Several studies have shown that a strong correlation between platelet-rich plasma and the stimulation of remodeling and remineralization of grafted bone exists, resulting in a possible increase of 15-30% in the density of bone trabeculae. The purpose of this study was to study the histopathological correlation between the use of platelet-rich plasma and a bone xenograft used in conjunction with a non-resorbable guided-tissue membrane, e-PTFE, compared to a control group with regards to bone regeneration at the implant fixture site. Implant fixtures were inserted and graft materials placed into the left femur of in the experimental group, while the control group received only implant fixtures. In the first experimental group, platelet-rich plasma and BBP xenograft were placed at the implant fixture site, and the second experimental group had platelet-rich plasma, BBP xenograft, and the e-PTFE membrane placed at the fixture site. The degree of bone regeneration adjacent to the implant fixture was observed and compared histopathologically at 2 , 4, and 8 weeks after implant fixture insertion. The results of the experiment are as follows: 1. The rate of osseointegration to the fixture threads was found to be greater in the first experimental group compared to the control group. 2. The histopathological findings of the second experimental group showed rapid resorption of BBP with subsequent new bone formation replacing the resorbed BBP. 3. The second experimental group showed new bone formation in the area adjacent to the fixture threads beginning two weeks after fixture implantation, with continued bone remodeling in the areas mesial and distal to the fixture. 4. Significant new bone formation and bone remodeling was observed in both experimental groups near the implant fixture sites. 5. The rate of osseointegration at the fixture threads was greater in the second experimental group compared to the first group, and the formation of new bone and trabeculae around the fixture site occurred after the fourth week in the second experimental group. The results of the experiment suggest that a greater degree of new bone formation and osseointegration can occur at the implant fixture site by utilizing platelet-rich plasma and bone xenografts, and that these effects can be accelerated and enhanced by concurrent use of a non-resorbable guided tissue membrane.

• 대한치과교정학회지
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• 제35권4호
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• pp.275-285
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• 2005

본 연구는 ipriflavone(isopropoxysioflavone)의 투여가 백서 두개관세포의 증식과 골조직 개조에 미치는 영향을 알아보고자 시도되었다. 태령 20-21일째의 백서 두개관세포를 분리 배양한 후, $10^{-9}M$부터 $10^{-5}M$까지 농도의 ipriflavone을 투여하고 1일째와 3일째에 MTT분석을 시행하여 흡광도를 평가한 결과, 모든 농도에서 백서 두개관세포의 증식을 보이지 않았다. 한편 골조직 개조에 미치는 영향을 알아보기 위하여 14일째에 alizarin red 염색을 시행하여, 형성된 석회화 결절 면적을 측정하였을 때, $10^{-8}M,\;10^{-7}M,\;10^-6}M$농도를 투여한 경우 석회화 결절 형성이 유의하게 증가하였다 골아세포의 분화에 미치는 영향을 알아보기 위하여 ipriflavone을 투여하고 7일째와 14일째에 추출한 RNA를 역전사 중합효소 연쇄반응(RT-PCR)을 시켜 bone sialoprotein(BSP), type I collagen(COL I) osteocalcin (OCN) 유전자 발현을 관찰한 결과 BSP와 COL I 유전자는 배양 7일째 높은 발현을 보였고, OCN 유전자는 배양 14일째 높은 발현을 보였다. 이상의 연구결과 ipriflavone이 백서 두개관세포에서 석회화를 촉진시키고 골아세포의 분화에 관여하는 BSP, COL I 및 OCN 유전자 발현을 증가시켜 골조직의 개조를 빠르게 할 수 있음을 시사하였다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제31권3호
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• pp.228-238
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• 2005

Purpose: Several cryoprotectants are in use to help the survival of cells during cryopreservation of bone in maxillofacial region. Among them, $Me_2SO$(dimethyl sulfoxide), EG(ethylene glycol), sucrose were used for experimentally created defects with accompanying cryopreserved bone graft in the rabbit model. The aim of this study is to analyze the effect of above mentioned agents on bone formation using histologic and histomorphometrical methods, thus to provide experimental support for clinical application of these agents. Materials and methods: Nine rabbits were used as experimental animals. Surgical defects were created on the distal femoral heads and mesial tibial heads of each animal using trephine drill(5mm diameter and 5mm length). The harvested bones were cryopreserved in $-80^{\circ}C$ refrigerator for one week. The defects were filled with cryopreserved bone with cryoprotectants as experimental groups and cryopreserved bone without cryoprotectant as control. Then, the animals were sacrificed at 1, 2, and 3 weeks after surgery. With Goldner's modified Masson trichrome staining and semiautomatic image analysis system, we observed the change of the cells and bone formation. Results: After bone graft, bone formation and active remodeling process were examined in all experimental groups and the control. But the intensity of such activities of the control were somewhat weaker than that of the experiments. Especially $Me_2SO$+sucrose group was the best in bone formation and bone remodeling. $Me_2SO$ group was more than that of EG group in bone fomation. Sucrose seems to be helpful in survival of the bone cell. Histologic findings showed superior bony quantity and quality in experimental groups than that in control. Conclusions: The data from this study provides the basis for future studies for evaluating the effect of cryoprotectants in the cryopreservation of bone and clinical study for predictable use of these agents.

• The Korean Journal of Physiology and Pharmacology
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• 제3권6호
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• pp.539-546
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• 1999

Bone is a complex tissue in which resorption and formation continue throughout life. The bone tissue contains various types of cells, of which the bone forming osteoblasts and bone resorbing osteoclasts are mainly responsible for bone remodeling. Periodontal disease represents example of abnormal bone remodeling. Osteoclasts are multinucleated cells present only in bone. It is believed that osteoclast progenitors are hematopoietic origin, and they are recruited from hematopoietic tissues such as bone marrow and circulating blood to bone. Cells present in the osteoclast microenvironment include marrow stromal cells, osteoblasts, macrophages, T-lymphocytes, and marrow cells. These cells produce cytokines that can affect osteoclast formation. In vitro model systems using bone marrow cultures have demonstrated that $IL-l{\beta},\;IL-3,\;TNF-{\alpha},$ bFGF can stimulate the formation of osteoclasts. In contrast, IL-4 inhibits osteoclast formation. Knowledge of cytokines and bFGF that affect osteoclast formation and their capacity to modulate the bone-resorbing process should provide critical insights into normal calcium homeostasis and disorders of bone turnover such as periodontal disease, osteoporosis and Paget's disease.

• 대한임상검사과학회지
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• 제48권2호
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• pp.114-117
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• 2016

골은 일생에 걸쳐 지속적인 재형성과장을 거치면서 유지되고 이러한 기전에 대한 연구는 골다공증을 비롯한 골대사 질환의 병태생리와 치료에 있어 큰 진전을 이루고 있다. 특히 생체 내 골형성 및 재생과정을 연구하는데 있어 형광표지자를 이용하는 방법이 널리 알려져 있는데, 그 중 calcein은 칼슘 킬레이터로 골이 새롭게 형성하는 부위에 녹색을 띔으로써 유용한 마커로 사용된다. 그러나 대부분의 골형성 연구에서 실험동물의 경우 표본제작을 할 때 크기가 작고 뼈가 부숴지기 쉬워 rat이나 rabbit을 이용하였으며, mice의 femur를 cross-section해서 관찰한 연구는 거의 없는 실정이다. 그래서 본 연구에서는 어린 mice를 실험동물로 이용하였으며, 생체 내 calcein을 4주간, 8주간 투여한 후 골 형성 변화를 형광현미경으로 관찰한 결과 8주차 쥐에서 4주차보다 진하고 골 형성 간격도 넓게 관찰된 것을 확인 할 수 있었다. Mice는 빠른 시일 내에 결과를 얻을 수 있고 부작용이 적은 장점이 있어서 앞으로 knock-out mice를 이용한 생체 내 실험에 활용하기 적합하다고 생각되며, 골형성 속도 평가 등 다양한 분야에서의 골 형성과 재생연구에 있어 기초 정보를 제공할 것으로 기대한다.

• Journal of Periodontal and Implant Science
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• 제35권1호
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• pp.235-250
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• 2005

The current interest in periodontal tissue regeneration has lead to research in bone graft, root surface treatments, guided-tissue regeneration, administration of growth factors, and the use of enamel matrix protein as possible means of regenerating lost periodontal tissue. Several studies have shown that a strong correlation between platelet-rich plasma and the stimulation of remodeling and remineralization of grafted bone exits, resulting in a possible increase of 15-30% in the density of bone trabeculae. The purpose of this study was to study the histopathological results and differences between the use of platelet-rich plasma and the use of enamel matrix $protein(Emdogain^?)$ about bone regeneration at the implant. Implant fixtures were inserted and graft materials placed into the left femur in the experimental group, while the only implant fixtures placed in the control group. In the first experimental group, platelet-rich plasma and xenograft were placed at the supracrestally placed implant site, and in the second experimental group, $Emdogain^{(R)}$ and xenograft placed at the supracrestally placed fixture site. The degree of bone regeneration adjacent to the implant fixture was observed and compared histopathologically at 2, 4, and 8 weeks after implant fixture insertion. The results of the experiment are as follows: 1. The rate of osseointegration to the fixture threads was found to be greater in the experimental group compared to in the control group. 2. The histopathological findings showed that the bone regeneration, the partial osseointegration existed at 4 weeks, and that osseointegration and bone density increaced in the experimental groups at 8 weeks. 3. The results showed that new bone formation and bone remodeling increased in the area near to the fixture in the first and second experimental groups at 8 weeks than at 4 weeks. The results showed that in the area distant from the fixture, new bone formation did not increase and bone remodeling decreased in the first experimental group at 4, 8 weeks, and that new bone formation increased in the second experimental group. 4. The histopathological findings showed that AZ deposition in the first experimental group was remarkable at 2, 8 weeks, and in the second experimental group at 2, 4, 8 weeks in the area distant from the fixture threads.

• 대한치과의사협회지
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• 제51권3호
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• pp.138-147
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• 2013

Orthodontic tooth movement is a unique process which tooth, solid material is moving into hard tissue, bone. Orthodontic force in general provides the strain to the PDL and alveolar bone, which in turn generates the interstitial fluid flow(in detail, fluid flow in PDL and canaliculi). As a results of matrix strain, periodontal ligament cells and bone cells are deformed, releasing variety of cytokines, chemokines, and growth factors. These molecules lead to the orthodontic tooth movement(OTM). In these inflammation and tissue remodeling sites, all of the cells could closely communicate with one another, flowing the information for tissue remodeling. To accelerate the rate of OTM in future, local injection of single growth factor(GF) or a combination of multiple GFs in the periodontal tissues might intervene to stimulate the rate of OTM. Corticotomy is effective and safe to accelerate OTM.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제31권6호
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• pp.469-477
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• 2009

육안적 검사결과 실험군과 대조군 모두에서 특별한 염증 소견이나 창상 이개 없이 반원 모양의 골형성이 관찰되었다. 조직학적으로 3주째에 대조군, 실험 1군, 실험2군, 실험 3군 모두 이식골 주위 및 티타늄 반구 내면을 따라 신생 골형성이 관찰되었다. 조직학적으로 6주째에 모든 군에서 3주째에 비하여 신생골 면적의 증가 및 성숙 소견이 관찰되었고, 실험2군에서는 부분적으로 이식골이 흡수되면서 신생골이 형성되는 것이 관찰된 반면, 실험 3군에서는 이식골의 흡수 소견이 관찰되지 않았다. 조직형태계측학적으로 3주, 6주 모두 자가골에서 가장 많은 신생골 형성이 나타났고, 신생골 면적 비교시 자가골, 이종골, 합성골 순으로 크게 나타났고, 각 군간의 통계학적으로 유의한 차이는 없었다(p>0.05). 본 연구결과 골유도 재생술시 골형성 능력은 자가골이 가장 좋지만, 자가골 채취가 불가능할 경우, 적절한 차폐막을 사용한 합성골과 이종골 복합 이식방식도 좋은 대체제가 될 것으로 생각된다.

• Restorative Dentistry and Endodontics
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• 제24권1호
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• pp.187-199
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• 1999

Bone remodeling is characterized by the continuing processes of osteoblast-mediated bone formation and osteoclast-mediated bone resorption. Bone metabolism is tightly regulated at the local level by networks of hormones, cytokines, and other factors. In pathological conditions of bone remodeling, including osteoporosis and periodontal diseases, inflammatory cytokines and local mediators are responsible for enhancement of osteoclast resorption and inhibition of repair at the sites of bone resorption. TNF-${\alpha}$ is a pleiotropic hormone with actions on the differentiation, growth, and functional activities of normal and malignant cells from numerous tissues. TNF-${\alpha}$ has been proposed as a local mediator of the control of bone turnover in situations of chronic inflammation, and it has been assumed that the local source of TNF-${\alpha}$ is the monocyte in the adjacent bone marrow or the local circulation. TNF-${\alpha}$ is a potent inducer of bone resorption. TNF-${\alpha}$ is known to induce the activation of apoptotic signaling pathway, which leads to the apoptosis of bone cells. We demonstrated that treatment of murine osteoblastic MC3T3E1 cells with TNF-${\alpha}$ decreases proliferation as well as alkaline phosphatase (ALP) activity in a dose depenent manner. In addition, TNF-${\alpha}$ increases osteoclast-like cell formation in $1{\alpha}$, 25(OH)2D3 or PGE2-treated bone marrow cell culture. When cells were cultured in TNF-${\alpha}$ free ${\alpha}$-MEM, this inhibitory effect of ALP activity was reversible up to 10 ng/ml TNF-${\alpha}$, in contrast, at the 20 ng/ml TNF-${\alpha}$, irreversible. In this concentration, TNF-${\alpha}$ may induce apoptosis in MC3T3E1 cells. In this study, TNF-${\alpha}$ induces apoptosis resulting in chromosomal DNA fragmentation, preceded by JNK/SAPKs and caspase-3 activation. Our present results show that JNK/SAPKs and caspase-3 are activated by TNF-${\alpha}$, suggesting that the JNK/SAPKs and caspase-3 participate in the bone resorption, associated with apoptosis.

• Journal of Periodontal and Implant Science
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• 제31권1호
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• pp.57-74
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• 2001

The purpose of this study was to evaluate the adjunctive combined effect of demineralized freeze-dried bone allograft(DFDB) in guided bone regeneration on supra-alveo-lar peri-implant defect. Supra-alveolar perio-implant defects, 3mm in height, each including 4 IMZ titanium plasma-sprayed implants were surgically created in two mongrel dogs. Subsequently, the defects were treated with 1 of the following 3 modalities: Control) no membrane or graft application, Group1) DFDB application, Group2) guided bone regeneration using an expanded polytetra-fluoroethylene membrane, Group3) guided bone regeneration using membrane and DFDB. After a healing period of 12-week, the animals were sacrificed, tissue blocks were harvested and prepared for histological analysis. Histologic examination were as follows; 1. New bon formation was minimal in control and Group 1, but considerable new bone formation was observed in Group 2 and Group 3. 2. There was no osteointegration at the implant-bone interface in the high-polished area of group2 and Group 3. 3. In fluorescent microscopic examination, remodeling of new bone was most active during week 4 and week 8. There was no significant difference in remodeling rate between group 2 and group 3. 4. DFDB particles were observed, invested in a connective tissue matrix. Osteoblast activity in the area was minimal. The results suggest that guided bone regeneration shows promising results in supra-alveolar peri-implant defects during the 12 week healing period although it has a limited potential in promoting alveolar bone regeneration in the high-polished area. There seems to be no significant adjunctive effect when DFDB is combined with GBR.