• Journal of Periodontal and Implant Science
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• v.38 no.2
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• pp.153-162
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• 2008

Purpose: Recombining bone morphogenetic protein (BMP) is usually acquiredfrom high level animals. Though this method is effective, its high cost limits its use. The purpose of this study was to evaluate the effect of bone morphogenetic protein-2 with protein transduction domain (BMP-2/PTD;TATBMP-2) on bone regeneration. Rat calvarial defect model and osteoblastic differentiation model using MC3T3 cell were used for the purpose of the study. Materials and Methods: MC3T3 cells were cultured until they reached a confluence stage. The cells were treated with 0, 0.1, 1, 10, 100, 500 ng/ml of BMP-2/PTD for 21 days and at the end of the treatment, osteoblastic differentiation was evaluated usingvon Kossa staining. An 8mm, calvarial, critical-size osteotomy defect was created in each of 48 male Spraque-Dawley rats (weight $250{\sim}300\;g$). Three groups of 16 animals each received either BMP-2/PTD (0.05mg/ml) in a collagen carrier, collagen only, or negative surgical control. And each group was divided into 2 and 8 weeks healing intervals. The groups were evaluated by histologic analysis(8 animals/group/healing intervals) Result: In osteoblastic differentiation evaluation test, a stimulatory effect of BMP-2/PTD was observed in 10ng/ml of BMP-2/PTD with no observation of dose-dependent manner. The BMP-2/PTD group showed enhanced local bone formation in the rat calvarial defect at 2 weeks. New bone was observed at the defect margin and central area of the defect. However, new bone formation was observed only in 50% of animals used for 2weeks. In addition, there was no new bone formation observed at 8 weeks. Conclusion: The results of the present study indicated that BMP-2/PTD(TATBMP-2) have an positive effect on the bone formation in vitro and in vivo. However, further study should be conducted for the reproducibility of the outcomes.

• Journal of Periodontal and Implant Science
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• v.38 no.2
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• pp.163-170
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• 2008

Purpose: Biphasic calcium phosphates have been of great interest recently. Mixing adequate ratios of hydroxyapatite(HA) and beta-tricalcium phosphate($\beta$-TCP) allowed to control the resorption rate without distorting its osteoconductive property. This study evaluated the bone formation effect of newly developed biphasic calcium phosphate(BCP) in calvarial defect of rabbits. Materials and Methods: 6 male New Zealand rabbits were used. Four defects with 8mm in diameter were created on each animal. BCP with HA/$\beta$-TCP ratio of 7:3 and particle size of $0.5{\sim}1.0\;mm$ was used as the test group and bovine bone with $0.25{\sim}1.0\;mm$ particle size, as the control group. Both test and control group materials were randomly implanted in the calvarial defects and were covered witha polymer membrane. The animals were sacrificed after 12, 24, and 48 weeks of implantation under general euthanasia. Resin blocks were obtained and were stained by masson's trichrome for histological observation. Results: Overall results were uneventful without any defect exposure or inflammation. The amount of new bone formation and bone maturity increased with increase in healing period at both groups. New bone in test group was mostly formed along the material particle surrounded by osteoblasts, and observation of osteoblastic stream was also present. Bone maturity increased as it was closer to thedefect margins. Under the same healing period, the test group showed more bone formation than the control group with more stable bovine bone particles remaining even after 48 weeks, whereas considerable resorption took place in BCP. Almost total defect closure was observed in test group with new bone formation in the central part of the defect. However, limited new bone formation was observed in the control group. Conclusion: Within the limits of the study, the present study reveals the newly developed BCP to be a good osteoconductive material. However, further studies are needed to be conducted in a different study model with a larger sample size.

• Journal of Periodontal and Implant Science
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• v.38 no.1
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• pp.59-66
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• 2008

Purpose: It has been shown that the inorganic polyphosphate is effective for the regeneration of bones through the preliminary animal test of rabbits. The most effective concentration of the polyphosphate, however, is not known yet. Moreover, the effectiveness of carriers inside human body is not confirmed.. Materials and Methods: In this study, we examined the effect of the concentration of the inorganic polyphosphate on the process of the bone regeneration using the 6 weeks old rabbits with the weight of 2.0 kg in average. We performed the experiment using TR-ePTFE membrane(membrane) filled with collagen immersed in 4%, 8% of inorganic polyphosphate, respectively, following removal of the proper sized cortical bones from the rabbit calvaria. The experimental results were compared with the one of the following four groups: The negative control group for membrane only, the positive control group for membrane filled with collagen, the first experimental group for membrane filled with collagen immersed in 4% of inorganic polyphosphate, and the second experimental group for membrane filled with collagen immerse in 8% of inorganic polyphosphate. The fragments of the tissue with membrane obtained from each group of the sacrificed rabbits for 8 or 16 weeks sustained after surgery were then prestained by the Hematoxylin-Eosin stain and coated by resin to form non-decalcified specimens for the histologic examination and analysis. New bone formation was assessed by histomorphometric and statistical analysis. Results: 1. All groups have shown better bone regeneration at 16weeks than 8weeks. 2. Negative control group has shown more bone regeneration relative to the other groups at 8 and 16 weeks. 3. All experimental groups have shown better bone regeneration relative to positive control group. 4. At 16 weeks, the first experimental group has shown more bone regeneration compared to the second experimental group. Exophytic bone formation is not good at the first and the second experimental groups compared with negative control group. But, the use of 4% inorganic polyphosphate was more effective to bone formation than the use of 8% inorganic polyphosphate. Conclusion: With above results, it is suggested the use of inorganic polyphosphate with vehicle under TR-ePTFE membrane.

• Journal of Periodontal and Implant Science
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• v.48 no.1
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• pp.34-46
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• 2018

Purpose: The purpose of this study was to evaluate the effects of 1,25-dihydroxyvitamin $D_3$ on the proliferation, differentiation, and matrix mineralization of MC3T3-E1 osteoblast-like cells in vitro. Methods: MC3T3-E1 osteoblastic cells and 1,25-dihydroxyvitamin $D_3$ were prepared. Cytotoxic effects and osteogenic differentiation were evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, alkaline phosphatase (ALP) activity assay, ALP staining, alizarin red S staining, and reverse transcription-polymerase chain reaction (RT-PCR) for osteogenic differentiation markers such as ALP, collagen type I (Col-I), osteocalcin (OCN), vitamin D receptor (VDR), and glyceraldehyde 3-phosphate dehydrogenase. Results: The MTT assay showed that 1,25-dihydroxyvitamin $D_3$ did not inhibit cell growth and that the rate of cell proliferation was higher than in the positive control group at all concentrations. ALP activity was also higher than in the positive control group at low concentrations of 1,25-dihydroxyvitamin $D_3$ ($10^{-10}$, $10^{-12}$, and $10^{-14}M$). RT-PCR showed that the gene expression levels of ALP, Col-I, OCN, and vitamin D receptor (VDR) were higher at a low concentration of 1,25-dihydroxyvitamin $D_3$ ($10^{-12}M$). Alizarin red S staining after treatment with 1,25-dihydroxyvitamin $D_3$ ($10^{-12}M$) showed no significant differences in the overall degree of calcification. In contrast to the positive control group, formation of bone nodules was induced in the early stages of cell differentiation. Conclusions: We suggest that 1,25-dihydroxyvitamin $D_3$ positively affects cell differentiation and matrix mineralization. Therefore, it may function as a stimulating factor in osteoblastic bone formation and can be used as an additive in bone regeneration treatment.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.4
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• pp.564-572
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• 2000

We decided among extraction, orthodontic traction and autotransplantation such as direction and position of unerupted tooth, degree of developing root apex, eruption space, being of supernumerary tooth or odontoma or cyst when tooth impacted. Autotransplantation is considered when orthodontic traction is unrealistic or when tooth movement can absorb root of neighbor tooth. The prognosis for successful autotransplantation is dependent on a number of factors such as root development, surgical technique, patient's age, endodontic treatment, time and type of splinting, preservation of periodontal ligament and storage medium. Especially when severe osseous defect is being, bone graft considered for reducing of mobility and for assisting recovery. In all cases, chief complaint is unerupted tooth and various causing factors were supernumerary, odontoma, ectopia and so on. Before autotransplantation, space regaining was done if needed and demineralized freezed dried bone and autogenous bone graft was done when there is severe osseous defect by extraction of supernumerary tooth or odontoma. Splinting was removed after 2-3weeks At 3-4weeks after autotransplantation, endodontic treatment was decided. At follow up check, normal recovery was done and there was no inflammatory or replacement root resorption in periapical radiograph.

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.1
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• pp.35-42
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• 2006

The developmental process of a tooth is being presented as an important study subject to analyze formation of normal dental arch and tooth. The purpose of this study was to see the formation of tooth from a tooth bud transplanted in a white rat regarding that the jawbone could be used as a new donor site of a trasplant. The first molar of a matured white rat was extracted and the tooth bud of a 13.5 day rat embryo was transplanted. The histological and radiographical results after 4 and 8 weeks respectively are as the following. 1. Calcification in dentin, cementum, pulp and periodontal ligament was formed from the tooth bud transplanted in the alveolar socket. 2. The development of hard and soft tissue was delayed compared to the normal tooth formation and abnormal histologic features such as ankylosis and osteodentin were found. 3. The formed hard tissue did not erupt into the jaw within 8 weeks.

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.1
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• pp.116-121
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• 2006

Familial hypophosphatemia is the most common hereditary rickets which occur hypophosphatemia as the calcium concentration in the blood serum is normal but the phosphate concentration in the blood serum decreases by dysfunction of renaltubular phosphorus reabsorption. In spite of the low concentration of phosphate in the blood serum discharge of phosphate by urine and alkaline phosphatase increases remarkably. It is a sex-linked and normally male show severe clinical symptoms than female. This kind of familial hypophosphatemia patients show frontal bossing, square head, short of status for general finding, and for dental finding, thinning of limina dura and dental follicle, thin and hypoplastic enamel, enlarged pulp chamber and canal, high occurance rate of periapical and periodontal abscess and unknown cause of rarefying osteitis. This case is to report about the clinical finging and dental treatment of a child patient, who came to the hospital for treatment of deciduous teeth caries but was refered to pediatrics because the child showed clinically short of status, bow-leg and radiographically enlarged pulp chamber and canal, there as diagnosed as familial hypophosphatemia.

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.2
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• pp.304-310
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• 2006

Prevotella intermedia is one of the most frequently implicated pathogens in human periodontal disease and has a requirement for hemin for growth. This study has identified a hemin-binding P. intermedia protein by expression of a P. intermedia genomic library in Escherichia coli, a bacterium which does not require or transport exogenous hemin. The genomic library of P. intermedia was constructed into plasmid pUC18, transformed into Escherichia coli strain $DH5{\alpha}$, and screened for recombinant clones using heminbinding activity by plating onto hemin-containing agar. Approximately 5,000 recombinant E. coli colonies were screened onto LB-amp-hemin agar, single clone(pHem1) was exhibited a clearly pigmented phonotype. The 2.5kb insert DNA of pHem1 was determined by restriction enzyme mapping. Southern blot analysis of BamHI, BglII, EcoRI, HindIII and PstI-digested P. intermedia DNA indicated that single copy of the gene was present in the genome. Northern blot analysis revealed that the size of transcript was approximately 1.8 kb. The cloned gene contained a single ORF, consisting of approximately 850-residue amino acids. A BLAST search of the Institute for Genomic Research genes with similar nucleotide sequence revealed no significant similarity It needs further investigation to clarify the mechanisms of heme uptake in P. intermedia.

• Journal of Dental Rehabilitation and Applied Science
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• v.31 no.3
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• pp.169-177
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• 2015

Purpose: The objects of this study were to examine the thickness of labial plate of anterior maxillary teeth and the gingival biotype in Koreans and to evaluate whether there is a correlation between the gingival biotype and the thickness of labial plate. Materials and Methods: This study was performed on 335 teeth of 57 subjects at the Pusan National University Dental Hospital. Cone Beam Computed Tomography (CBCT) was used to measure the thickness of labial plate at 4 mm, 6 mm, 8 mm from the cementoenamel junction and the gingival biotype was determined by the visibility of periodontal probe. Results: Thin facial bone less than 1 mm was observed in 87% at 4 mm, 88% at 6 mm and 90% at 8 mm. In 21% of total objects, thin gingival biotype was observed. There is no correlation between the thickness of labial plate and gingival biotype. Conclusion: Additional thorough radiographic examination such as CBCT was mandatory for aesthetic dental implant in the anterior dentition besides clinical oral examination.

• Journal of dental hygiene science
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• v.2 no.2
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• pp.63-67
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• 2002

The purpose of this study was to develop more effective dental health education program and to reduce the occurrence of dental diseases among industrial men-workers in Korea. The questionaire and dental examination were given to 782 industrial men-workers who visited Asan Medical Center for the purpose of health examinations in 2000. The obtained results were as follows; 1. According to the results of logistic regression analysis, both ages (especially under 30's: P=0.027) and monthly incomes (especially under 1,000,000 won: P=0.000) show negative relationships with the occurrence of dental caries. 2. As the results of logistic regression analysis, ages shows positive relationship and monthly incomes shows negative relationship (only under 1,000,000 won: P=0.059) with the occurrence of missing teeth. 3. According to the results of logistic regression analysis of periodontal disease, the model shows no significance (P=0.117). 4. As the results of logistic regression analysis, both monthly incomes and ages show positive relationships with the occurrence of abrasion.