• 대한치주과학회:학술대회논문집
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• 대한치주과학회 2007년도 제47회 종합학술대회 연제초록
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• pp.112-112
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• 2007

• 대한치주과학회:학술대회논문집
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• 대한치주과학회 2007년도 제47회 종합학술대회 연제초록
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• pp.148-149
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• 2007

• 대한치주과학회:학술대회논문집
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• 대한치주과학회 2002년도 제42회 종합학술대회 연제초록
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• pp.34-35
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• 2002

• Bulletin of the Korean Chemical Society
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• 제28권4호
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• pp.652-656
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• 2007

Hydroxyapatite [Ca10(PO4)6(OH)2, HAp] and titanium(Ti) metal are known to be excellent materials with high affinities for natural bone through the apatite. Tricalcium phosphate [Ca3(PO4)2, TCP] is a promising alternative material because it is similar to HAp in its physical properties and biocompatibility. To examine the influence of hydroxyapatite, tricalcium phosphate, pure titanium and pre-treated titanium on osteopontin expression in osteoblasts, RNA was extracted from proliferated and cultured osteoblast cells and OPN mRNA expression was observed by RT-PCR.

• Journal of Periodontal and Implant Science
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• 제38권4호
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• pp.595-602
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• 2008

Purpose: Ti-6Al-4V alloy is widely used as an implant material because of its good biocompatibility and good mechanical property compared with commercial pure titanium. Otherwise, toxicity of aluminum and vanadium in vivo has been reported. Ti-8Ta-3Nb alloy is recently developed in the R&D Center for Ti and Special Alloys and it was reported that this alloy has high mechanical strength, no cytotoxicity and similar biocompatibility to commercial pure titanium, but many studies are needed for its clinical use. In these experiment, we carried out different surface treatment on each Ti-8Ta-3Nb alloy disks, then cultured cell on it and assessed biological response. Materials and Methods: cpTi, Ti-6Al-4V, Ti-8Ta-3Nb alloy disks were prepared and carried out sandblasting and acid etching (SLA) or alkali-heat treatment (AH) on the Ti-8Ta-3Nb alloy disks. We cultured primary rat calvarial cells on each surface and assessed early cell attachment and proliferation by scanning electron microscopy, cell proliferation, alkaline phosphatase activity. Result: The rates of cell proliferation on the cpTi, Ti-8Ta-3Nb AH disks were higher than others (p<0.05) and alkaline phosphatase activity was significantly enhanced on the Ti-STa-8Nb AH disks(p<0.05). Conclusion: Most favorable cell response was shown on the Ti-8Ta-3Nb AH surfaces. It is supposed that alkali-heat treatment of the Ti-8Ta-3Nb alloy could be induced earlier bone healing and osseointegration than smooth surface.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제21권1호
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• pp.1-12
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• 1999

The purpose of this study was to evaluate the healing process of the calvarial defect filled with hydroxylapatite(HA) and $TGF-{\beta}$ in Rat. 72 Sprague-Dawly rats were divided into 3 groups, control and two experimental groups. Bony defect were artificially prepared in the calvaria of all 72 rats and followed by implantation of HA (experimental group of 24 rats) and HA+$TGF-{\beta}$(another experimental group of 24 rats) into the defects. Sequential sacrifice was performed at 1, 2, 4, 6, 8, 12 weeks of experiment. Obtained specimen was stained with Hematoxylin and Eosin, Masson's Trichrome and Immunohistochemistry. The results were as follows, 1. Granulation tissue was prominent on control group in 1 and 2 weeks. Bony defects were filled with dense fibrous tissue through the whole experimental period and osteoinduction could not be observed in all groups. 2. Inflammatory cell infiltration was prominent on control group in 1 and 2 weeks and osteoclastic activity was high in HA implanted experimental group at 1 and 2 weeks. 3. Inflammatory cell infiltration was less and maturation of fibrous tissue could be found on HA+$TGF-{\beta}$ implanted experimental group at 1 and 2 weeks. 4. Osteoconduction activity was high in HA+$TGF-{\beta}$ implanted experimental group at 2 and 4 weeks but there was no difference after 6 weeks among 3 groups. 5. In grafted site of HA+$TGF-{\beta}$ implanted group, osteonectin expression was slightly increased from 1 week to 6 weeks. In the host site, it was increased from 1 to 4weeks. 6. In grafted site of HA+$TGF-{\beta}$ implanted group, osteocalcin expression was high at 4 weeks. In the host site, we could find the difference among 3 groups. From above results, the HA with mixture of $TGF-{\beta}$ has the potentiality of promoting bone formation in the bony defect area in the rat.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제32권4호
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• pp.360-373
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• 2006

The purpose of this research was to investigate whether pulsed electromagnetic field (PEMF) stimulation applied to the rabbit cranial defects grafted with ${\beta}$-tricalcium phosphate (${\beta}$-TCP) could affect the new bone formation. With 16 New Zealand white rabbits under the same condition, bilateral calvarial bone defects were formed around the sagittal suture line. The defect on the left side was grafted with ${\beta}$-TCP, while on the right side was grafted by harvested autogenous bone. PEMF was applied to 8 rabbits for 8 hours per day. The bony specimen were divided into 3 groups, the group 1 was autogenous bone grafted specimen, the group 2 was ${\beta}$-TCP grafted with PEMF, and the group 3 was ${\beta}$-TCP grafted without PEMF. We investigated the bone regeneration & growth factor expression at 2, 4, 6, and 8 weeks. As a result, BMP 2 was expressed in the group 1 from 2 weeks, the group 2 from 4 weeks, and the group 3 from 6 weeks. BMP 4 was expressed in the group 1 from 2 weeks, in the group 2 and the group 3 from 4 weeks. 4. There was no significant difference in expression pattern of BMP 7, PDGF, VEGF, and TGF-${\beta}$1 during grafted bone regeneration in group 1, 2, and 3. According to our results, PEMF stimulation could be effective on the new bome formation in animal study, and have a feasibility of clinical use.

• Journal of Periodontal and Implant Science
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• 제25권2호
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• pp.192-209
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• 1995

The purpose of this study was to evaluate drug-loaded biodegradable membranes for guided tissue regeneration(GTR). The membranes were made by coating mesh of polyglycolic acid(PGA) with polylactic acid(PLA) containing 10% flurbiprofen or tetracycline. The thickness of membrane was $150{\pm}30{\mu}m$, and the pore size of surface was about $8{\mu}m$ in diameter. The release of drugs from the membrane was measured in vitro. Cytotoxity test for the membrane was performed by gingival fibroblast cell culture, and the tissue response was observed after implant of membrane into the dorsal skin of the rat for 8 wks. Ability to guided tissue regeneration of membranes were tested by measuring new bone in the calvarial defects(5mm in diameter) of the rat for 5 weeks. The amount of flurbiprofen and tetracycline released from membrane were about 30-60% during 7 days. Minimal cytotoxity was observed in the membrane except 20% drug containing membrane. In histologic finding of rat dorsal skin, many inflammatory cells were observed around e-PTFE, polyglactin 910 and PLAPGA membrane after 1 or 2 weeks. PLA-PGA membrane was perforated by connective tissue after 4 or 6 weeks, and divided as a segment at 8 weeks. In bone regeneration guiding potential test, tetracycline loaded membrane was most effective (p

• International Journal of Oral Biology
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• 제31권2호
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• pp.53-65
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• 2006

Calcium concentration in the bone resorption lacunae is high and is in the mM concentration range. Both osteoblast and osteoclast have calcium sensing receptor in the cell surface, suggesting the regulatory role of high extracellular calcium in bone metabolism. In vitro, high extracellular calcium stimulated osteoclastogenesis in coculture of mouse osteoblasts and bone marrow cells. Therefore we examined the genes that were commonly regulated by both high extracellular calcium and $1,25(OH)_2vitaminD_3(VD3)$ by using mouse oligo 11 K gene chip. In the presence of 10 mM $[Ca^{2+}]e$ or 10 nM VD3, mouse calvarial osteoblasts and bone marrow cells were co-cultured for 4 days when tartrate resistant acid phosphatase-positive multinucleated cells start to appear. Of 11,000 genes examined, the genes commonly regulated both by high extracellular calcium and by VD3 were as follows; 1) the expression of genes which were osteoclast differentiation markers or were associated with osteoclastogenesis were up-regulated both by high extracellular calcium and by VD3; trap, mmp9, car2, ctsk, ckb, atp6b2, tm7sf4, rab7, 2) several chemokine and chemokine receptor genes such as sdf1, scya2, scyb5, scya6, scya8, scya9, and ccr1 were up-regulated both by high extracellular calcium and by VD3, 3) the genes such as mmp1b, mmp3 and c3 which possibly stimulate bone resorption by osteoclast, were commonly up-regulated, 4) the gene such as c1q and msr2 which were related with macrophage function, were commonly down-regulated, 5) the genes which possibly stimulate osteoblast differentiation and/or mineralization of extracellular matrix, were commonly down-regulated; slc8a1, admr, plod2, lox, fosb, 6) the genes which possibly suppress osteoblast differentiation and/or mineralization of extracellular matrix, were commonly up-regulated; s100a4, npr3, mme, 7) the genes such as calponin 1 and tgfbi which possibly suppress osteoblast differentiation and/or mineralization of extracellular matrix, were up-regulated by high extracellular calcium but were down-regulated by VD3. These results suggest that in coculture condition, both high extracellular calcium and VD3 commonly induce osteoclastogenesis but suppress osteoblast differentiation/mineralization by regulating the expression of related genes.

• Journal of Periodontal and Implant Science
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• 제33권4호
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• pp.585-597
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• 2003

Porphyromonas gingivalis has been implicated as an important periodontophathic bacterium in the etiology and progression of periodontal diseases. It has been reported that P.gingivalis may mediate periodontal destruction not only directly through its virulence factors, but also indirectly by including complex host mediated inflammatory reponses. The purpose of this study was t o evaluate the effects of P.gingivalis on the bone formation and resorption by osteoblasts. For this purpose, after determining the concentration below which sonicated P.gingivalis extracts (SPEs) have no cytotoxicity on mouse calvarial primary osteoblastic (POB) cells, we investigated the effects of SPEs on the alkaline phosphatase (ALP) activity, matrix metalloproteinase (MMP) expression (MMP-2, -9, 13), and prostaglandin $E_2$ ($PGE_2$) release in POB cells by treatment with SPEs below that concentration. The results were as follows; 1. SPEs showed no cytotoxic effect on POB cells up to a concentration of 1 ${\mu}m$/ml. 2. The treatment with SPEs reduced ALP activity in a dose-dependent manner in POB cells, In addition, when we investigated the effect of SPEs (1 ${\mu}m$/ml) on ALP activity for different exposure periods, statistically significant inhibition of ALP activity was shown at 2 days of exposure, and further significant inhibition occurred by extending the periods of exposure. 3. The treatment with SPEs stimulated the gene expression of MMP-9 in POB cells. 4. The pre-treatment with SPEs increased the amount of $PGE_2$ released in POB cells. In summary, the present study shows that P.gingivalis could inhibit osteogenesis and stimulate bone resorption not only by reducing ALP activity but also by increasing MMP-9 mRNA expression in osteoblasts, possibly through an endogenous $PGE_2$ pathway. In addition, our results suggest that if P.gingivalis affects osteoblasts in early differentiation stage, such effects by P. gingivalis could be irreversible.