• Journal of Periodontal and Implant Science
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• v.37 no.4
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• pp.871-879
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• 2007

Purpose: The purpose of this study was to evaluate the bone regeneration of novel biodegradable amorphous calcium phosphate. Materials and Method: An 8-mm, calvarial, critical-size osteotomy defect was created in each of 20 male Sprague-Dawley rats(weight $250{\sim}300g$). The animals were divided into two groups of 10 animals each and allowed to heal for 2 weeks(10 rats). The first group was the control group and the other group was the experimental group which received the novel biodegradable calcium phosphate. Results: The healing of the calvarium in the control group was uneventful. The histologic results showed little bone formation in the control group. The experimental group which received the novel biodegradable calcium phosphate showed a normal wound healing. There were a lot of new bone formation around the biomaterial in 2 weeks. The bone formation increased in 8 weeks when compared to 2 weeks and there was a significant bone increase as well(P<0.01). The nobel biodegradable calcium phosphate showed statistical significance when compared to the control group (P<0.05). The novel biodegradable calcium phosphate in 8 weeks showed a significant increase in bone formation when compared to 2 weeks $(40.4{\pm}1.6)$(%). The biodegradable calcium phosphate which is made from mixing calcium phosphate glass(CPG), NaCO and NaOH solution, is biocompatible, osteoconductive and has a high potency of bone formation. Conclusion: We can conclude that the novel biodegradable calcium phosphate can be used as an efficient bone graft material for its biodegradability and osteoconductivity.

• Restorative Dentistry and Endodontics
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• v.17 no.1
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• pp.134-140
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• 1992

The purpose of this study was to investigate the antibacterial effect of zinc oxide eugenol(ZOE), zinc phosphate cement(ZPC), glass ionomer cement, resin, and Vitapex to S. muntans, S. sanguis, S. fecalis and E. coli by agar diffusion method. Four wells were punctured in mitis-salivarius agar plate per each group and each wells were filled with restorative matetials. The width of inhibition zones produced in mitis - salivarius agar were measured as the parameter of the antibacterial effect after 16 hours and 40 hours. In S. mutans and S. sanguis, the largest inhibition zone was produced on ZOE, followed by glass ionomer cement, and ZPC. Inhibition zones was not observed in resin and Vitapex. In S. fecalis, ZOE and glass ionomer cement showed wider inhibition zone than ZPC. In E. coli, ZOE showed wider inhibition zone than ZPC, but no inhibition zone was observed on glass ionomer cement.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.31 no.2
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• pp.92-95
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• 2020

Tracheal granuloma, the most commonly reported sequela of pediatric tracheotomy. A variety of techniques are available for the management of tracheal granuloma. Potassium-titanyl-phosphate (KTP) laser has been previously established as an acceptable technique for removal of laryngeal surgery, which emits a green light with a wave length of 532 nm, which is well-absorbed by hemoglobin and can coagulate and vaporize tissue. The ability to deliver laser energy through a flexible glass fiber makes the technique convenient for use with a rigid bronchoscope, overcoming problems with intraluminal access encountered with earlier attempts at CO2 laser therapy for this problem. Another advantage of KTP laser is the avoidance of the risks and morbidity associated with an open procedure. We report our surgical technique KTP laser in the management of tracheal granuloma removal into the tracheostomy site. KTP laser is good tool for management of tracheal granuloma with low incidence of complications.

• The Journal of Korean Academy of Prosthodontics
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• v.30 no.1
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• pp.93-101
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• 1992

The purpose of this study was to evaluate the effectiveness of core materials and luting agents on the retention of full veneer gold crown. The core materials used in this study was dental amalgam, and composite resin, and the luting agents were zinc phosphate cement, polycarboxylate cement, and glass ionomer cement. The obtained results were as follows. 1. In full veneer gold crown supported by composite resin core, the crown retention with zinc phosphate cement was the highest of all. 2. In full veneer gold crown supported by amalgam core, the crown retention was shown no statistical difference by luting agent. 3. There was no statistical difference in the crown retention between the full veneer gold crown supported by composite resin core and dental amalgam core.

• The Journal of Korean Academy of Prosthodontics
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• v.36 no.1
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• pp.26-49
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• 1998

The purpose of this study was to confirm the formation of hybrid layer and resin tags in dentin tissue and the possibility of bonding between luting cements used for the prosthesis and the resinous surface coated with resin bonding agents to prevent the dentin hypersensitivity after abutment preparation. Some resin bonding agents, which may have the possibility of bonding with polyacrylic acid as a liquid ingredient of polycarboxylate and glass ionomer cements, were selected. All-Blond desensitizer containing NTG-GMA and BPDM, Scotch-Bond Multipurpose plus containing HEMA, and XR-bond containing organophosphate were selected as a coating agent. Dental cements were zinc phosphate, polycarboxylate, and glass ionomer cement. After the exposed dentin surface of premolars was ethced with 10% phosphoric acid and coated with resin bonding agents, the morphology of treated surfaces and the resin tags and hybrid layers on sectioned surfaces were observed by SEM. Shear bond strength between the resin bonding agents and 3 kinds of cements was measured 24 hours after bonding. On the debonded surfaces of the shear bond strength tested specimens, the cement tags and the bonding sites between the resin materials and cements were examined by SEM. Following conclusions were drawn : 1. Coating of dentin with resin bonding agents had no effect on the shear bond strength of zinc phosphate cement. 2. Both of polycarboxylate and glass ionomer cements showed the increased shear bond strength by the dentinal coating with Scotch-Bond Multipurpose plus containing HEMA. However, in the case of dentinal coating with some agents containing NTG-GMA and BPDM or organophosphate, polycarboxylate cement exhibited the lowered shear bond strength, and glass ionomer cement showed the unchanged shear bond strength. 3. Complete obstructions of dentinal tubules were observed on the dentin coated with All-Bond desensitizer or XR-bond, but distinct shape of the orifices of dentinal tubules was observed consistently on the dentin coated with Scotch-Bond Multipurpose plus. 4. The hybrid layer was thickest on the dentin coated with All-Bond desensitizer, and the length of resin tags was longest on the dentin coated with Scotch-Bond Multipurpose plus. 3. On the debonded specimens which had been bonded with polycarboxylate cement or glass ionomer cement after coating with Scotch-Bond Multipurpose plus, the cement tags and the bonding sites between the resinous surface and the cements could be examined.

• Korean Journal of Microbiology
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• v.44 no.4
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• pp.289-292
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• 2008

Trisodium phosphate 12 hydrate and citric acid monohydrate mixture showed the strong anti-sticking effect on Streptococcus mutans, Streptococcus mitis, and Streptococcus salivarius, which are adhered to glass beads. Each Streptococcus species was shaking-cultured in brain heart infusion broth containing three glass beads. After 18 hr, glass beads were slightly washed into normal saline by three-pin-pointed pincette. Each three glass-beads set was put into reagent -containing tubes, which have 40 mg of bits of weighing paper for gaining brushing effect as similar as brushing one's teeth. The tubes were shaken by vortex mixer for 10 min except non-oral microbe, Streptococcus agalactiae (5 min). The samples were colony-counted by serial agar dilution method. Experiment was repeated three times for each Streptococcus species. The relative ratios of bacterial de-adherence by reagents were calculated in comparison with normal saline control. The de-adherence degree of citric acid-trisodium phosphate-saline mixture (CTS, pH 6.0) against Streptococcus mutans came to an average of 12.5 times compared with normal saline control. Trisodium-saline (TS, pH 8.4) showed the average of 7.5 times, and citric acid-saline (CS, pH 4.6) showed 6.0 times compared to the control group. The bacterial de-adherence degree against Streptococcus salivarius was each 7.2,2.6 and 2.8 times in above reagent sequence in comparison with saline control. CTS and TS showed 2.4 and 3.4 times of anti-sticking effect on Streptococcus mitis respectively, but CS had no anti-sticking effect on this bacterium. CTS, TS and CS showed 0.7, 0.6, and 0.6 times on non-oral microbe, Streptococcus agalactiae, separately compared with saline control. These results show that oral Streptococcus mutans, Streptococcus salivarius, and Streptococcus mitis, which are causative of dental caries or subacute endocarditis, may be easily removed from oral cavity by CTS mixture. It is conceivable that our experimental results will enable the development of a new conceptive toothpaste to prevent dental caries or subacute endocarditis after drawing teeth.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.53.1-53.1
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• 2011

Bioactive glass powders were synthesized by hydrothermal chemical route by the use of ultrasonic energy irradiation. We used sodalime, calcium nitrate tetra hydrate and di ammonium hydrogen phosphate as the precursor material to synthesize $SiO_2$ rich bio-active glass materials. The $SiO_2$ content was varied in the precursor mixture to 60, 52 and 45 mole%. Dense compacts were obtained by microwave sintering at $1,100^{\circ}C$. Mechanical properties were characterized for the fabricated dense bioactive glasses and were found to be comparable with conventional CaO-$SiO_2$-$Na_2O$-$P_2O_5$ bioactive glass. Detailed biocompatibility evaluation of the glass composition was investigated by in-vitro culture of MG-63 cell and mesenchyme stem cell. Cell adhesion behavior was investigated for both of the cell by one cell morphology for 30, 60 and 90 minutes. Cell proliferation behavior was investigated by culturing both of the cells for 1, 3 and 7 days and was found to be excellent. Both SEM and confocal laser scanning microscopy were used for the investigation. Western blot analysis was performed to evaluate the bimolecular level interaction and extent and rate of specific protein expression. The ability to form biological apatite in physiological condition was observed with simulated body fluid (SBF). In-vivo bone formation behavior was investigated after implanting the materials inside rabbit femur for 1 and 3 month. The bone formation behavior was excellent in all the bioglass compositions, specially the composition with 60% $SiO_2$ content showed most promising trend.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.391-394
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• 2003

It is inevitable that reconsideration of the use of lead oxides in the electronics industry be undertaken as long as detrimental effects to the environment remain. To solve this problem, many recent studies on Pb-free compositions for PDP (plasma display panel) dielectric layers and also sealing glass compositions have been made. The present study was conducted to investigate whether the alternative systems for leadfree low firing glasses, detailed below, are available for use in PDP materials. The results suggest that low-melting phosphate glasses would be suitable as an alternative material for the Pb-based dielectric layer, sealants and barrier ribs in PDP.

• Proceedings of the Optical Society of Korea Conference
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• 2002.07a
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• pp.102-103
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• 2002

금속 입자들이 채워진 유리는 광 호변성 물질로써 광 저장 디스크, 광 도파로 그리고 도파로 레이저, 광 스위치 등의 다양한 응용분야에 이용될 수 있음이 여러 연구진들에 의해서 밝혀져 왔다. [1] 광 호변성이란 외부에서 입사되는 광에 의해서 유리의 색이 변색되는 현상인데 이는 유리에 함유된 물질들이 광이나 열에 의해서 변화하기 때문이다. Wood 등은 열처리와 불꽃에 의한 가열 등을 이용하여 은 입자를 작은 입자로 쪼개고. 이를 엑시머 레이저로 열처리시키면 은 입자가 분해된다는 것을 보였다. (중략)

• Journal of the Korean Ceramic Society
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• v.23 no.5
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• pp.75-80
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• 1986

The mechanical properties were measured for magnesium phosphate glasses containing small amounts of water. The decrease in hardness with increasing water content was resulted from a looser chain structure caused by water. The fracture of these glasses was changed from brittle fracture to plastic deformation as a results of the increased viscous flow with increasing water contents. The extent of any viscous flow or deformation initiating from the crack tips in these glasses could be considered as quite small.