• Journal of Korean Dental Science
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• 제3권1호
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• pp.32-38
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• 2010

Objective : To evaluate the relationship between the dose of Clodronate and serum level of alkaline phosphatase (ALP), calcium (Ca), and phosphate (PO4) during orthodontic tooth movement MaterialS and MethodS: A total of 18 sex-matched Wistar rats (weight=180~230g, mean age=8 weeks) were allocated into the 2.5mM Clodronate (2.5C) group, 10mM Clodronate (10C) group, or control group (n=6 for each group). After the application of a nickel-titanium closed coil spring (force of 60g) between the upper central incisors and first molars (UFM), 2.5C, 10C, or saline was injected every third day into the subperiosteum of the alveolar bone adjacent to UFM for the experimental and control groups. The animals were sacrificed 17 days later. Trunk blood was quickly collected into a heparinized tube and centrifuged at 2,000 rpm for 20 min. The plasma was used for the biochemical assays of the serum level of ALP, Ca, and PO4. Kruskall-Wallis test and Mann-Whitney test with Bonferroni correction were performed for the statistical analyses. Results : Dose-dependent increase in the level of ALP (P<0.01) and decrease in the level of Ca (P<0.001) were observed among the control, 2.5C, and 10C groups. Although there was no significant difference in PO4 between the 2.5C and 10C groups, the 10C group showed a significantly higher level of PO4 than the control group (P<0.01). Conclusion : Since Clodronate induced significant dose-dependent change in the serum level of ALP, Ca, and PO4 during orthodontic tooth movement, orthodontists should consider these biochemical markers not only as a diagnostic tool for bone turnover rate but also as a monitoring tool for orthodontic tooth movement.

• KSBB Journal
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• 제14권2호
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• pp.241-247
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• 1999

디프테리아는 Corynebacterium diphtheriae에 의해 발생되는 호흡기 질병으로 C. diphtheriae의 exo-toxin을 불활성화 시킨 toxoid 백신을 사용하여 예방해 왔다. 현재까지 국내에서는 정치배양 방법으로 디프테리아 toxin을 생산해 왔기 때문에 생산성과 품질에 한계가 있었으며, 이를 극복하기 위해 발효조를 이용한 발효조건 최적화에 대한 연구를 수행하였다. 디프테리아 toxin을 보다 효율적을 얻기 위한 배지로서 beef antigen이 함유되어 있지 않은 casein 유래의 NZ-Case를 선택하였다. 발효조에 의한 toxin 생성은 세포성장과 함께 증가하는 growh-associated form으로 나타났다. 최대의 세포성장과 toxin 생성은 초기 pH가 7.0인 배지에서 0.22vvm의 통기와 400rpm의 교반조건에서 얻을 수 있었다. 또한 최대의 toxin 생성을 위한 최적의 iron 이온의 농도는 0.3mg/L 이었으며, morgamcphospale의 첨가에 의한 calcium-phosphate 침전이 배지 내에 iron 이온의 농도조절을 위하여 요구되었다. 면역원성을 확인하기 위한 역가시험 결과 발효조 배양에서 얻은 toxoid는 4단위에서 모든 guinea-pigs가 생존하여 2단위인 정치배양 toxin에비해 월등히 우수한 것으로 판단되었다. 결국 발효조 배양으로 toxin을 생산할 경우 부작용이 적고 수율과 생산성 및 면역원성 이 우수한 toxid의 생산이 가능하였다.

• 한국재료학회지
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• 제17권12호
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• pp.669-675
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• 2007

Hydroxyapatite (HAp) and biphasic calcium phosphate (BCP) nano powders were synthesized using the microwave-assisted synthesis process dependent on pH and microwave irradiation time. The average size of a powder was less than 100 nm in diameter. Through in-vitro cytotoxicity tests by an extract dilution method, the HAp and BCP nano powders have shown to be cytocompatible for L-929 fibroblast cells, osteoblastlike MG-63 cells and osteoclast-like Raw 264.7 cells. The activation of osteoblast was estimated by alkaline phosphatase (ALP) activity. When the HAp and BCP were treated to MG-63 cells, alkaline phosphatase activities increased on day 3, compared with those of the untreated cells. Also, the collagen fibers increased when the HAp and BCP powders suspension were treated to MG-63 cells, compared to those of the untreated cells. Quantitative alizarin red S mineralization assays showed a trend toward increasing mineralization in osteoblast cultured with powder suspension. In conclusion, hydroxyapatite and biphasic calcium phosphate appeared to be a bone graft substitute material with optimal biocompatibility and could be further applied to clinical use as an artificial bone graft substitute.

• Journal of Periodontal and Implant Science
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• 제41권5호
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• pp.242-247
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• 2011

Purpose: The purpose of this study was to characterize the osseointegration of the fibronectin-coated implant surface. Methods: Sand-blasted, large-grit, acid-etched (SLA) surface implants, with or without a thin calcium phosphate and fibronectin coating, were placed in edentulous mandibles of dogs 8 weeks after extraction. All dogs were sacrificed forhistological and histomorphometric evaluation after 4- and 8-week healing periods. Results: All types of implants were clinically stable without any mobility. Although the bone-to-implant contact and bone density of the SLA implants coated with calcium phosphate (CaP)/fibronectin were lower than the uncoated SLA implants, there were no significant differences between the uncoated SLA surface group and the SLA surface coated with CaP/fibronectin group. Conclusions: Within the limits of this study, SLA surfaces coated with CaP/fibronectin were shown to have comparable bone-to-implant contact and bone density to uncoated SLA surfaces.

• The Journal of Advanced Prosthodontics
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• 제10권3호
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• pp.177-183
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• 2018

PURPOSE. The purpose of the current study was to evaluate the effect of incorporating nanoparticles of silver (NAg) and amorphous calcium phosphate (NACP) into a self-etching primer of a resin cement on the microtensile bond strength of dentin, regarding the proven antibacterial feature of NAg and remineralizing effect of NACP. MATERIALS AND METHODS. Flat, mid-coronal dentin from 20 intact extracted human third molars were prepared for cementation using Panavia F2.0 cement. The teeth were randomly divided into the four test groups (n=5) according to the experimental cement primer composition: cement primer without change (control group), primer with 1% (wt) of NACP, primer with 1% (wt) of physical mixture of NACP+Nag, and primer with 1% (wt) of chemical mixture of NACP+Nag. The resin cement was used according to the manufacturer's instructions. After storage in distilled water at $37^{\circ}C$ for 24 h, the bonded samples were sectioned longitudinally to produce $1.0{\times}1.0mm$ beams for micro-tensile bond strength testing in a universal testing machine. Failure modes at the dentin-resin interface were observed using a stereomicroscope. The data were analyzed by one-way ANOVA and Tukey's post-hoc tests and the level of significance was set at 0.05. RESULTS. The lowest mean microtensile bond strength was obtained for the NACP group. Tukey's test showed that the bond strength of the control group was significantly higher than those of the other experimental groups, except for group 4 (chemical mixture of NACP and NAg; P=.67). CONCLUSION. Novel chemical incorporation of NAg-NACP into the self-etching primer of resin cement does not compromise the dentin bond strength.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제33권4호
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• pp.301-307
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• 2011

Purpose: If the tooth structure is damaged, then it is impossible to regenerate the tooth. The materials used to restore the tooth structure are not related to the composition of the tooth. The materials used to restore the structure can't replace the natural tooth because they just fill the defective structure. Calcium phosphate cement remineralizes the dentin and almost replaces the natural tooth, but there are some disadvantages. We conducted basic tests with Biomimetic CPC (Bio-CPC) to make sure of the possibility of the biomaterial to remineralize the defective tooth structure. Methods: In this study, the bioactivity and biocompatibility of Bio-CPC were evaluated for its potential value as the bio-material for regeneration of damaged tooth structure by conducting a cell toxicity assay (WST-1 assay), a cytokinesis-block micronucleus assay, a chromosomal aberration test, total RNA extraction and RT-PCR on MDPC-23 mouse odontoblast-like cells. Results: The in vitro cytotoxicity test showed that the Bio-CPC was fairly cytocompatible for the MDPC-23 mouse odontoblast-like cells. Conclusion: Bio-CPC has a possibility to be a new biomaterial and further study of Bio-CPC is needed.

• The Journal of Advanced Prosthodontics
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• 제6권2호
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• pp.96-102
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• 2014

PURPOSE. This study was performed to characterize the effects of zirconia coated with calcium phosphate and hydroxyapatite compared to smooth zirconia after bone marrow-derived osteoblast culture. MATERIALS AND METHODS. Bone marrow-derived osteoblasts were cultured on (1) smooth zirconia, (2) zirconia coated with calcium phosphate (CaP), and (3) zirconia coated with hydroxyapatite (HA). The tetrazolium-based colorimetric assay (MTT test) was used for cell proliferation evaluation. Scanning electron microscopy (SEM) and alkaline phosphatase (ALP) activity was measured to evaluate the cellular morphology and differentiation rate. X-ray photoelectron spectroscopy (XPS) was employed for the analysis of surface chemistry. The genetic expression of the osteoblasts and dissolution behavior of the coatings were observed. Assessment of the significance level of the differences between the groups was done with analysis of variance (ANOVA). RESULTS. From the MTT assay, no significant difference between smooth and surface coated zirconia was found (P>.05). From the SEM image, cells on all three groups of discs were sporadically triangular or spread out in shape with formation of filopodia. From the ALP activity assay, the optical density of osteoblasts on smooth zirconia discs was higher than that on surface treated zirconia discs (P>.05). Most of the genes related to cell adhesion showed similar expression level between smooth and surface treated zirconia. The dissolution rate was higher with CaP than HA coating. CONCLUSION. The attachment and growth behavior of bone-marrow-derived osteoblasts cultured on smooth surface coated zirconia showed comparable results. However, the HA coating showed more time-dependent stability compared to the CaP coating.

• Journal of Periodontal and Implant Science
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• 제45권4호
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• pp.136-144
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• 2015

Purpose: The objective of this study was to comparatively assess the bone regenerative capacity of absorbable collagen sponge (ACS), biphasic calcium phosphate block (BCP) and collagenated biphasic calcium phosphate (CBCP) loaded with a low dose of recombinant human bone morphogenetic protein-2 (rhBMP-2). Methods: The CBCP was characterized by X-ray diffraction and scanning electron microscopy. In rabbit calvaria, four circular 8-mm-diameter defects were created and assigned to one of four groups: (1) blood-filled group (control), (2) rhBMP-2-soaked absorbable collagen sponge (0.05 mg/mL, 0.1 mL; CS group), (3) rhBMP-2-loaded BCP (BCP group), or (4) rhBMP-2-loaded CBCP (CBCP group). The animals were sacrificed either 2 weeks or 8 weeks postoperatively. Histological and histomorphometric analyses were performed. Results: The CBCP showed web-like collagen fibrils on and between particles. Greater dimensional stability was observed in the BCP and CBCP groups than in the control and the CS groups at 2 and 8 weeks. The new bone formation was significantly greater in the BCP and CBCP groups than in the control and CS groups at 2 weeks, but did not significantly differ among the four groups at 8 week. The CBCP group exhibited more new bone formation in the intergranular space and in the center of the defect compared to the BCP group at 2 weeks, but a similar histologic appearance was observed in both groups at 8 weeks. Conclusions: The dose of rhBMP-2 in the present study enhanced bone regeneration in the early healing period when loaded on BCP and CBCP in rabbit calvarial defects.

• Membrane and Water Treatment
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• 제9권3호
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• pp.163-172
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• 2018

This study investigated the effect of organic matter on the precipitation of struvite and calcium phosphate for phosphorus recovery from synthetic dairy wastewater. Batch precipitation experiments were performed to precipitate phosphorus from solutions containing $PO_4{^{3-}}$ and $NH_4{^+}$ by the addition of $Mg^{2+}$ and $Ca^{2+}$, separately, at varying pH, Mg/P and Ca/P molar ratios, and organic matter concentrations. Soluble total organic solids exhibited more inhibition to precipitation due to potential interaction with other dissolved ionic species involved in phosphorus precipitation. Xylan with low total acidity only exhibited significant inhibition at very high concentrations in synthetic wastewater (at up to 100 g/L). No significant inhibition was observed for Mg and Ca precipitation at relatively lower concentrations (at up to 1.2 g/L). MINTEQ simulations show that dissolved organic matter (DOM) as humic substances (HS) can cause significant inhibition even at relatively low concentrations of 0.165 g/L fulvic acid. However, scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis suggested that xylan altered the crystal structure of both precipitates and had caused the formation of smaller sized struvite crystals with slightly rougher surfaces This could be due to xylan molecules adhering on the surface of the crystal potentially blocking active sites and limit further crystal growth. Smaller particle sizes will have negative practical impact because of poorer settleability.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1998년도 추계학술대회
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• pp.231-232
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• 1998

The purpose of this study was to examine whether the precipitation of calcium phosphate on titanium surface was affected by surface modification. To improve the bone conductivity, of titanium, samples were devided into 4 groups. Group 1 was immersed in 5M-NaOH solution at $60^{\circ}C$ for 24 hours. Group 2 was immersed in 5M-NaOH solution at $60^{\circ}C $ for 24 hours and heat-treated at $600^{\circ}C$ for 1 hour. Group 3 was anodized in Hanks' solution at 1V, $25^{\circ}C$ for 1 hour. Group 4 was anodized in Hanks' solution at 5V, $80^{\circ}C$ for 5 minutes. And then, all specimens were immersed in the MEM Eagle's medium whose composition was similar to that of extracellular fluid for 30 days. The precipitation of the calcium phosphate on implant surface was increased by the immersion in the NaOH solution, and more highly accelerated by heat treatment at $600^{\circ}C$. The precipitation of the calcium phosphate on titanium implant was increased with the treatment of the anodic oxidation in Hanks' solution at 5V, $80^{\circ}C$.