• The korean journal of orthodontics
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• v.35 no.4 s.111
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• pp.262-274
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• 2005

Tooth movement is a result of mutual physiologic responses between the periodontal ligament and alveolar bone stimulated by mechanical strain. The PDL cell and osteoblast are known to have an influence on bone formation by controlling collagen synthesis and alkaline phosphatase activation. Moreover. recent studies have shown that the PDL cell and osteoblast release osteoprotegerin (OPG) and the receptor activator of nuclear factor ぉ ligand (RANKL) to control the level of osteoclast differentiation and activation which in turn influences bone resorption. In this study. progressively increased, continuous tensional force was applied to PDL cells. The objective was to find out which kind of biochemical reactions occur after tensional force application and to illuminate the alveolar bone resorption and apposition mechanism. Continuous and progressively increased tensile force was applied to PDL cells cultured on a petriperm dish with a flexible membrane The amount of $PGE_2$ and ALP synthesis were measured after 1, 3, 0 and 12 hours of force application. Secondly RT-PCR analysis was carried out for OPG and RANKL which control osteoclast differentiation and MMP-1 -8, -9, -13 aud TIMP-1 which regulate the resolution of collagen and resorption of the osteoid layer According to the results. we concluded that progressively increased, concluded force application to human PDL cells reduces $PGE_2$ synthesis, and increases OPG mRNA expression.

• Journal of Acupuncture Research
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• v.26 no.5
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• pp.65-75
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• 2009

Objectives : Pyrite is one of the important prescriptions that has been used in oriental medicine for healing of fracture. It is reasonable, therefore, to postulate that native copper affects the process of bone metabolism and bone formation. The purpose of this study is to discover the effect of Pyrite on the healing of tibia fracture. Methods : 1. In vitro test : MG-63 cell in human body and the Pyritum in the ratio of 0.5mg/ml, 1.0mg/ml, 1.5mg/ml, 2.0mg/ml were incubated for 24 hours. After 24 hours, RNA was extracted via trizol reagent (Sigma, USA). In order to understand the activation of osteoblast, the level of OPN mRNA, osteopontin, was measured. 2. In vivo tesgroups normal group, control group and experimental group. Left tibia bones of mice in CON and JT groups were fractured by bone cutters. Pyrite was orally administered to the experimental group. After 14 days, each group's tibia specimen was constructed to observe changes in activation of proinflmmatory cytokines in relation to MIF and IL-6. Also, proliferation of osteoblast and osteopontin were measured via changes in levels of OPN and OPN mRNA. Results : In jn-Titro test, the level of OPN mRNA, osteopontin production was remarkably increased in Pyritum-treated MG-63 cells. In in-vitro test, fractured area in external tibia morphology was increased more in the JT group than that of the CON group. Osteogenesis, endochodrial ossification, and osteoid in fractured area were also increased more in the JT group than that of the CON group. Increase in OPN mRNA, osteopontin level and osteoblast's proliferation were observed. Activation of MIF and IL-6 was confirmed from the fracture region. Conclusions : From the result, development of a new stimulator in healing fracture via pyrite is expected.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.11 no.1
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• pp.101-116
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• 1989

Proplast and Porous Polyethylene which have porous structures as low-modulus polymers have been recently used in maxillofacial plastic and reconstructive surgery. The purpose of this study was to compare the response of adajacent tissue, new bone formation and stability after augmentation by differen methods of subperiosteal graft using proplast and purous polythylene in rabbit mandible. The augmentation procedure was carried out by dividing into two groups, A and B. A group consisted of subperiosteal graft on the cortex, and the other B group was made up only graft following artificial decortication in the mandibular body of rabbit. The experimental animals were sacrificed on the 1st, 2nd, 4th and 8th week after grafting for macroscopic and light microscopic examination. The samples extracted at the 6th postgrafting week were also used for biometric testing and scanning electron microscopic examination. The results obtained from this study were as follows : 1. Macroscopically, infection of graft site, deformation and migration of graft material were not observed in all experimental groups. 2. B group showed more rapid and increased bone formation and the greater stability than A group, and tissue response was similar to each other. 3. In the tissue response, macrophages and cellular infiltrations were observed in Proplast group, but few in PHDPE group. 4. In bone formation of A group, Proplast group showed no bone formation until the 8th week, but PHDPE group showed small quantity of osteoid tissue from the 2nd week and appositional bone growth with new bone formation at the 8th week. 5. In bone formation of B group, both Proplast and PHDPE group showed bone formation, but PHDPE group showed more rapid and larger bone formation. 6. In pattern of bone formation, Proplast group mainly showed appositional bone growth pattern connected with graft site. On the other hand, PHDPE group showed mixed pattern of new bone formation in the pore connective tissue with appositional bone growth from graff site. 7. The maximum mean values of shear stress were serially $111.3gf/mm^{2}$ in PHDPE of B group, $84.8gf/mm^{2}$ in PHDPE of A group, $32.9gf/mm^{2}$ in Proplast B group, and $15.7gf/mm^{2}$ in Proplast of A group. From above results, It was suggested that the capacity of bone formation and stability between bone and graft material were dependent on the pore size and structure of graft material itself, the state of graft site and tissue response.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.27 no.3
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• pp.248-258
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• 2005

The challenging task of classifying the fibro-osseous(FO) lesions has been previously attempted but only in the past 15 years has the entire spectrum of diversity been appreciated. For the clinicians, it is hard to clearly diagnose the lesions before operations. The purpose of this study was to review the literature about fibro-osseous lesions of the jaws and to analyse our clinical cases. As the results of the review of clinical features, radiography and histopathologic findings of sixteen cases of fibro-osseous lesions, we could elucidate diagnostic aids for treatment of benign FO lesion in jaws. Six patients involving fibrous dysplasia complained the facial swelling and facial asymmetry. The radiographic features of the lesions showed ground-glass radiopacity mostly and the histologic findings showed typically Chinese character-shaped trabeculae without osteoblastic rimming in the fibrous stroma. Six patients with ossifying fibroma were notified as swollen buccal cheek state. Their radiographic findings showed cortical expanded radiolucent lesion with sclerotic defined border, which was contrast to the normal adjacent bone. The lesions showed variant radiolucent lesions. Histological findings were revealed as cellular fibrous stroma with woven bones, variable patterns of calcifications. Three patients with cemental dysplasia didn't have specific complaints. Well circumscribed radiopaque lesions on mandibular molar area were observed. Cementum-like ossicles with fibrous stroma were found on microscopic findings. A osteoblastoma case with jaw pain was found. The radiographic feature was a mottled, dense radiopacity with osteolytic border on mandibular molar area. Under microscopy trabecule of osteoid with vascular network were predominantly found. Numerous osteoblast cells with woven bone were found. These clinical, radiographic and microscopic findings of benign fibrous-osseous lesions would suggest diagnostic criteria for each entity of FO lesions.

• Journal of Periodontal and Implant Science
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• v.40 no.3
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• pp.132-138
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• 2010

Purpose: The purpose of this study was to compare the bone regeneration effects of cortical, cancellous, and cortico-cancellous human bone substitutes on calvarial defects of rabbits. Methods: Four 8-mm diameter calvarial defects were created in each of nine New Zealand white rabbits. Freeze-dried cortical bone, freeze-dried cortico-cancellous bone, and demineralized bone matrix with freeze-dried cancellous bone were inserted into the defects, while the non-grafted defect was regarded as the control. After 4, 8, and 12 weeks of healing, the experimental animals were euthanized for specimen preparation. Micro-computed tomography (micro-CT) was performed to calculate the percent bone volume. After histological evaluation, histomorphometric analysis was performed to quantify new bone formation. Results: In micro-CT evaluation, freeze-dried cortico-cancellous human bone showed the highest percent bone volume value among the experimental groups at week 4. At week 8 and week 12, freeze-dried cortical human bone showed the highest percent bone volume value among the experimental groups. In histologic evaluation, at week 4, freeze-dried cortico-cancellous human bone showed more prominent osteoid tissue than any other group. New bone formation was increased in all of the experimental groups at week 8 and 12. Histomorphometric data showed that freeze-dried cortico-cancellous human bone showed a significantly higher new bone formation percentile value than any other experimental group at week 4. At week 8, freeze-dried cortical human bone showed the highest value, of which a significant difference existed between freeze-dried cortical human bone and demineralized bone matrix with freeze-dried cancellous human bone. At week 12, there were no significant differences among the experimental groups. Conclusions: Freeze-dried cortico-cancellous human bone showed swift new bone formation at the 4-week healing phase, whereas there was less difference in new bone formation among the experimental groups in the following healing phases.

• Polymer(Korea)
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• v.27 no.3
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• pp.226-234
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• 2003

Ipriflavone (IP), a non-hormonal isoflavone derivative, has been shown to interfere with bone remodeling by inhibiting bone resorption and stimulating bone formation. IP consistently increased the amount of Ca incorporated into the cell layer by mesenchymal stem cells (MSCs). In this study, we developed the novel IP loaded poly(L-lactide-co-glycolide) (PLGA) scaffolds for the possibility of the application of the tissue engineered bone. IP/PLGA scaffo1ds were prepared by solvent casting/salt leaching method and were characterized by porosimeter, scanning electron microscopy, determination of residual salt amount, differential scanning calorimetry, and X-ray diffractometer, respectively. IP/PLGA scaffolds were implanted into the back of athymic nude mouse to observe the effect of IP on the osteoinduction compared with control PLGA scaffo1ds. Thin sections were cut from paraffin embedded tissues and histological sections were stained H&E, von Kossa, and immunohistochemical staining for Type I collagen and osteocalcin. It can be observed that the porosity was above 91.7% and the pore size was above 101 $\mu\textrm{m}$. Control scaffo1d and IP/PLGA scaffo1ds of 50% IP were implanted on the back of athymic nude mouse to observe the effect of IP on the induction of cells proliferation for 9 weeks. The evidence of calcification, osteoblast, and osteoid from the undifferentiated stem cells in the subcutaneous sites and other soft connective tissue sites having a preponderance of stem cells has been observed. From these results, it seems that IP plays an important role for bone induction in IP/PLCA scaffolds.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.32 no.3
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• pp.241-249
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• 2006

Purpose For the reconstruction of craniofacial deformities, the distraction osteogenesis is an useful method which can make new soft tissues as well as new bone. Although the distraction osteogenesis is an effective procedure in quantitative aspects, the new bone formed by this procedure can be coarse in qualitive aspects sometimes. Materials and methods Twelve rabbits, weighing about 2 kg, were included and the prefabricated distraction device were used. After a latency period of 5 days, in the experimental group (n=6), the mandible was distracted at the rate of 1.0 mm/day for 2 days and then compressed with 1.0 mm for the next 3rd day, therefore distracted totally to a length of 1.0 mm for 3 days. This procedure was repeated 5 times and, as a result, the experimental group was distracted to a length of 5.0 mm for 15 days finally. In the control group (n=6), the mandible was distracted totally to a length of 5.0 mm at the rate of 1 mm/day. At 2 weeks and 8 weeks of consolidation in the control group, 3 rabbits in each group were sacrificed and their biopsy specimens from the distracted mandible were taken. Results All animals showed the mandibular elongation clinically and radiographically. Histologically, many blood vessels, osteoblasts and immature bones formed by osteoid deposition were observed in the experimental group at 2 weeks. At 8 weeks, the bony trabeculae were thicker than the ones in the control group and were composed of lamella bones and woven bones in the experimental group. On histomorphometric analysis, the bone deposition area of the distracted site was broader in the experimental group $(273.8{\pm}115.7\;cm^2)$ than the one in the control group $(199.4{\pm}101.4\;cm^2)$. Futhermore, the modified rate of bone deposition area was higher in the experimental group (48${\pm}$20%) than the one in the control group (35${\pm}$18%). However, these data showed no significant differences statistically. Conclusion These results suggest that the distraction osteogenesis by using an alternating distraction/compression protocols is an effective method for increasing new bone formation in distracted areas.

• Korean Journal of Oriental Medicine
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• v.6 no.1
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• pp.123-132
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• 2000

Bone is continuously remodeled during adult life with the resorption of old bone by osteoclasts and its subsequent replacement by osteoblast. Bone homeostasis is maintained by a balance between activities of osteoblasts and osteoclasts, but an imbalance between resorption and formation results in bone diseases including osteoporosis. Osteoblasts line up on the bone surface, especially regions of new bone formation, lay down bone matrix (osteoid) in orderly lamellae and induce its mineralization. Thus, the increased activity of osteoblasts is helpful to treat and prevent osteoporosis. In this study, we examined whether 80% EtOH extract of yukmijiwhang-whan is capable of affecting osteoblast proliferation using human osteoblast-like cell line, MG-63 and Saos-2. In an in vivo experiment, extract of yukmijiwhang-whan was administered for 9 weeks to ovariectomized (OVX) rats. At necropsy, uterus weights were measured, and trabecular bone areas (TBAS) of tibia and the sixth lumbar vertebra were measured by bone histomorphology. The maximum cell proliferation of MG-63 caused by extract of yukmijiwhang-whan at $5\;{\times}\;10^{-6}\;mg/ml$ was approximately 115% compared with control. In Saos-2, cell proliferation was approximately 145% of control at $5\;{\times}\;10^{-4}\;mg/ml$ and maximum alkaline phosphatase (ALP) activity was approximately 143% of control at $5\;{\times}\;10^{-5}\;mg/ml$. In animal study, however, the tibia and lumbar TBAS of the yukmijiwhang-whan group did not increased than the OVX control group. In conclusion, the 80% EtOH extract of yukmijiwhang-whan increased proliferation of osteoblasts but did not prevent bone loss in OVX rats.

• Journal of Periodontal and Implant Science
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• v.31 no.1
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• pp.73-91
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• 2001

The present study was performed to compare effects of demineralized freeze-dried bone allograft(DFDBA) with deproteinized bovine bone mineral(DBBM) on periodontal fenestration defect in rats. Twelve adult male rats weighing 500 to 540 grams were used in this study. Periodontal fenestration defects were surgically created with tapered fissure bur(${\Phi}1mm$) at the left side of buccal surface of the mandible. The defect size was from anterior border of the first molar to anterior of the ascending ramus mesiodistally and from just below the alveolar crest to apically 1.5-2mm area apicocoronally with 2mm in depth. Rats were divided into control group, test group I and II. Four defects were assigned to the test group I grafted with DBBM and other 4 defects were assigned to the test group II grafted with DFDBA. The rest of defects were the negative control group. At 10 days and 35 days after surgery, 12 rats were sacrificed through intracardiac perfusion and specimens were obtained prepared with Hematoxylin-Eosin stain for light microscopic evaluation. The results of this study were as follows : 1. In the control group, new bone, osteoid, dense connective tissue were observed in the defects at 10 days. new bone formation was not found but loose connective tissue was formed in the defect and fibrous encapsulation of graft materials was shown in two test groups at 10 days. 2. In all groups, new bone formation was shown in the defect at 35 days. And in the control group, bone formation increased at 35 days than at 10 days. 3. In the test group I and II at 35 days, graft materials were combined with new bone and joined host bone. There was very close contact between new bone, graft materials, and host bone with no gaps. 4. In the test group I and II, new bone formation was similar to that in the control group but not exeeded. In conclusion, in the test group I new bone formation was similar to that in the test group II at 35 days, but there was infiltration of inflammatory cells at 10 days. DFDBA and DBBM were considered as the biocompatible graft materials and effective in the regeneration of new bone.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.27 no.1
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• pp.15-24
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• 2001

The purpose of this study is to evaluate the tissue response in applying of various bone substitutes included toothash-plaster mixture, resorbable hydroxylapatite (HA) and demineralized freeze-dried bone and to show the clinical usefulness of toothash-plaster mixture for the repair of craniomaxillofacial bone defect. For this experiment, 100 Sprague-Dawley rats weighing 200gm or more were used. There were four experimental groups: group I, toothash-plaster mixture; group II, demineralized freeze-dried bone; group III, resorbable HA; and group IV, control group. A full thickness, round bone defect measuring 10mm in diameter was created in the midcranium, and the substitutes cited above were embedded in the experimental rats based on their group assignment. Blood clot was filled in the rats assigned to the control group. Experimental rats were sacrificed on the 1st, 3rd, 5th, 8th, 12th and 24th week after implantation and stained with the hematoxylineosin, Masson's Trichrome, using Van Gieson's stain method, and were examined under light microscope. The results were as follows: 1. In all the groups, prominent inflammatory reaction and the infiltration of multinucleated giant cells were noted during the early stage. Gradual healing decreased this reaction. 2. Among the rats in the experimental group II, which were given demineralized freeze-dried bone implants, active formation of new bone traveculae manifested. Chondroid tissues appeared, and it was suggested that the defect was filled with newly formed bone by virtue of osteoinductive activity. On the 12th week after the experiments, most of the defect was filled with newly formed bone trabeculae. 3. In experimental groups I and III, it was noted that HA manifested a healing process similar to that characterized by the toothash-plaster mixture, but inflammatory reaction was more prominent in experimental group I. Active osteoblasts were observed along the periphery of osteoid tissues, while newly formed bone trabeculae appeared adjacent to the implanted materials three weeks later. Formation increased to the extent that newly formed bone trabeculae fused directly with the host bone. Increase in new bone ingrowth into the filling materials was revealed by both experimental groups. 4. In the control group, new bone formation adjacent to the host bone was observed, but most of the defect was filled with mature connective tissue 24 weeks after the experiments.