• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.548-548
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• 2012

Thermomechanical and surface chemical properties of composite films of poly(D, L-lactic-co-glycolic acid) (PLGA) were significantly improved by the addition of graphene oxide (GO) nanosheets as nanoscale fillers to the PLGA polymer matrix. Enhanced thermomechanical properties of the PLGA/GO (2 wt.%) composite film, including an increase in the crystallization temperature and reduction in the weight loss, were observed. The tensile modulus of a composite film with increased GO fraction was presumably enhanced due to strong chemical bonding between the GO nanosheets and PLGA matrix. Enhanced hydrophilicity of the composite film due to embedded GO nanosheets also improved the biocompatibility of the composite film. Improved thermomechanical properties and biocompatibility of the PLGA composite films embedded with GO nanosheets may be applicable to biomedical applications such as scaffolds.

• KSBB Journal
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• 제25권5호
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• pp.409-420
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• 2010

Biopolymer-based materials recently have garnered considerable interest as they can decrease dependency on fossil fuel. Biopolymers are naturally obtainable macromolecules including polysaccharides, polyphenols, polyesters, polyamides, and proteins, that play an important role in biomedical applications such as tissue engineering, regenerative medicine, drug-delivery systems, and biosensors, because of their inherent biocompatibility and biodegradability. However, the insolubility of unmodified biopolymers in most organic solvents has limited the applications of biopolymer-based materials and composites. Ionic liquids (ILs) are good solvents for polar organic, nonpolar organic, inorganic and polymeric compounds. Biopolymers such as cellulose, chitin/chitiosan, silk, and DNA can be fabricated from ILs into films, membranes, fibers, spheres, and molded shapes. Various biopolymer/biopolymer and biopolymer/synthetic polymer composites also can be prepared by co-dissolution of polymers into IL mixtures. Heparin/biopolymer composites are especially of interest in preparing materials with enhanced blood compatibility.

• 대한금속재료학회지
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• 제50권9호
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• pp.691-695
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• 2012

Calcium phosphate ceramic composites, consisting of hydroxyapatite(HA) and tricalcium phosphate (TCP), were fabricated by solid state sintering in order to investigate the effect of their initial compositions on microstructural evolutions and biocompatibility. All the sintered calcium phosphate ceramics exhibited almost full densification, while the grain growth of the composites increased with an increasing TCP content in the green body. The TCP phase transformed into a Ca-deficient HA phase during sintering via the diffusion of calcium ions from the HA phase into the TCP phase. The phases formed in the composites significantly affected the biocompatibility of the composites. The HA-matrix ceramic composites with TCP had a better cellular response than the pure HA ceramics, presumably due to the newly formed Ca-deficient HA.

• 치위생과학회지
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• 제21권4호
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• pp.243-250
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• 2021

Background: Endodontic sealers or their toxic components may become inflamed and lead to delayed wound healing when in direct contact with periapical tissues over an extended period. Moreover, an overfilled sealer can directly interact with adjacent tissues and may cause immediate necrosis or further resorption. Therefore, the treatment outcome conceivably depends on the endodontic sealer's biocompatibility and osteogenic potential. This study aimed to evaluate the cell viability and osteogenic effects of four different sealers in osteoblastic cells. Methods: AH Plus (resin-based sealer), Pulp Canal Sealer EWT (zinc oxide-eugenol sealer), BioRoot RCS (calcium silicate-based sealer), and Well-Root ST (MTA-based calcium silicate sealer) were mixed strictly according to the manufacturer's instructions, and dilutions of sealer extracts (1/2, 1/5 and 1/10) were determined. Cell viability was measured using the water-soluble tetrazolium-8 (WST-8) assay. Differentiation was assessed by alkaline phosphatase (ALP) activity and mineralized nodule formation by Alizarin Red S staining. Results: The cell viability of the extracts derived from the sealers excluding Well-Root ST was concentration dependent, with sealer extracts having the least viability at a 1/2 dilution. At sealer extract dilution of 1/10, the test groups showed the same survival rate as that control group, with the exception of BioRoot RCS. Among all experimental groups, BioRoot RCS showed the highest cell viability after 48 hours. The ALP activity was significantly higher in a concentration-dependent manner. Furthemore, all four materials promoted ALP activity and mineralized nodule formation compared to the control at 1/10 dilutions. Conclusion: This is the first study to highlight the differences in biological activity of these four materials. These results suggest that the composition of root canal sealers appears to alter the form of biocompatibility and osteoblastic differentiation.

• 대한치주과학회:학술대회논문집
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• 대한치주과학회 2007년도 제47회 종합학술대회 연제초록
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• pp.97-98
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• 2007

• 대한금속재료학회지
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• 제50권1호
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• pp.86-91
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• 2012

Ti-6Al-4V extra low interstitial (ELI) alloy has been widely used as an orthopedic implant material because of its excellent biocompatibility, corrosion resistance and mechanical properties. However, V-free titanium alloys such as Ti-6%Al-7%Nb and Ti-5%Al-2.5%Fe have recently been developed because of the toxicity of V. Hydroxyapatite (HA) is used as a coating material on Ti or Ti biomaterials due to its good biocompatibility. However, HA coated on Ti alloy causes a problem for tissue by peeling off during usage. Therefore, such peeling off during long time usage can be suppressed by adding HA in Ti or Ti alloy composites. The aim of this study was to manufacture an ultra fine grained (UFG) Ti-Nb-HA bulk alloy, which is usually difficult to fabricate using melting and casting technology, by rapid sintering process using high energy mechanical milled (HEMM) powder.

• Restorative Dentistry and Endodontics
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• 제25권1호
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• pp.63-70
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• 2000

The properties of ideal retrograde filling materials include the ability to seal the root canal system in three dimensions and well tolerated by periradicular tissues. Biocompatibility testing has been done mainly with cytotoxicity tests using cell culture. Little attention has been paid to the potential adverse influence on the inflammatory and immune reaction in the periapical tissue. The purpose of this study was to investigate the effects of retrograde filling materials on human mononuclear cells in vitro. Freshly mixed and set specimens from six materials (Z100, Tetric Ceram, Fuji II, Fuji II LC, F2000, Compoglass Flow, and ZOE) were eluated with cell culture medium for 24 hours. Cytotoxic effects of these extracts were evaluated by determining cell viability and enzyme activity using MTT and lactate dehydrogenase (LD). The production of inflammatoy bone resorptive cytokine, TNF-${\alpha}$ was measured from human peripheral blood mononuclear cells (PBMC) exposed to the extracts by means of Endogen Human TNF-${\alpha}$ ELISA kit (Wobrun, MA, U.S.A.). Eluates and diluted (1 : 10) eluates with cell culture medium from freshly mixed Fuji IT had cytotoxic effects on mononuclear cells using MTT and LD. However, eluates from set Fuji II were not cytotoxic. Eluates form set ZOE exhibited cytotoxicity with LD test. TNF-${\alpha}$ levels were high in eluates from freshly mixed Fuji II and Z100. Diluted eluates from freshly mixed Z100 and F2000 stimulated the production of TNF-${\alpha}$. However, there were no significant difference in TNF-${\alpha}$ levels compared to controls. These results indicate that some materials could possibly stimulate bone resorption in the periapical tissue by means of the production of bone resorptive cytokine.

• 대한의용생체공학회:의공학회지
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• 제14권3호
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• pp.257-264
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• 1993

A study on the biocompatibility of two types of new glass-ceramics materials, metal disc and dental porcelain that were already made for dental artificial tooth in the previous study, have been attempted. The chemical behavior and the Victor's hardness change in she artificial saliva and Ringer's solution have been also investigated. From the experiment of Implantation of glass-ceramics Into dorsal subcutaneous tissue of Sprague-Dawley rats, glass-cerarmics did not show any particular system of rejection for histrocompatibility.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2012년도 춘계학술발표대회
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• pp.102.2-102.2
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• 2012

Different layers of zirconium nitride (ZrN) and hydroxyapatite (HA) coatings were prepared on cp Ti substrate for biomedical applications. The main idea is to improve the mechanical strength as well as the biocompatibility of the coating. ZrN is known for its high mechanical strength, corrosion resistance. HA is well known for its biocompatibility properties. Hence, in this study, both materials were coated on a cp Ti substrate with bottom layer with ZrN for good bonding with substrate and the top layer with HA for induce bioactivity. Middle layer was formed by a composite of HA and ZrN. Detail analyses of the layered coatings for its structural, morphological, topographical properties were carried out. Then the mechanical property of the layered coatings was analyzed by nanoindentation. Biomimetic growths of apatite on the functionally graded coatings were determined by simulated body fluid method. This study provides promising results to use this kind of coatings in biomedical field.

• The Journal of Advanced Prosthodontics
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• 제12권3호
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• pp.157-166
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• 2020

PURPOSE. The aim of this study was to evaluate the clinical performance and reliability of plasma sprayed nanostructured zirconia (NSZ) coating. MATERIALS AND METHODS. This study consisted of three areas of analysis: (1) Mechanical property: surface roughness of NSZ coating and bond strength between NSZ coating and titanium specimens were measured, and the microstructure of bonding interface was also observed by scanning election microscope (SEM). (2) Biocompatibility: hemolysis tests, cell proliferation tests, and rat subcutaneous implant test were conducted to evaluate the biocompatibility of NSZ coating. (3) Mechanical compatibility: fracture and artificial aging tests were performed to measure the mechanical compatibility of NSZ-coated titanium abutments. RESULTS. In the mechanical study, 400 ㎛ thick NSZ coatings had the highest bond strength (71.22 ± 1.02 MPa), and a compact transition layer could be observed. In addition, NSZ coating showed excellent biocompatibility in both hemolysis tests and cell proliferation tests. In subcutaneous implant test, NSZ-coated plates showed similar inflammation elimination and fibrous tissue formation processes with that of titanium specimens. Regarding fatigue tests, all NSZ-coated abutments survived in the five-year fatigue test and showed sufficient fracture strength (407.65-663.7 N) for incisor teeth. CONCLUSION. In this study, the plasmasprayed NSZ-coated titanium abutments presented sufficient fracture strength and biocompatibility, and it was demonstrated that plasma spray was a reliable method to prepare high-quality zirconia coating.