• Journal of Periodontal and Implant Science
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• 제24권1호
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• pp.144-154
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• 1994

Final goal of periodontal treatment is to reconstruct the destructed periodontal tissue as well as to remove the necrotic pathologic elements. The purpose of this study is to investigate on the effect of Zizyphi extract to the inhibitory ability on collagenolytic activity of P gingivalis, biologic activity of gingival fibroblasts, and on the collagen and protein synthesis of gingival fibroblasts. Gingival fibroblast from giniva of first bicuspids from patient for orthodontic treatment were used and cultured. For the measurement of inhibitory ability of collagenolytic activity, crude enzyme was extracted and used on the basis of modified Ono's method. On the inhibition of collagenolytic enzyme from herbal extracts, collagenokit CLN-100 were used. The cellular activity of gingival fibroblast, were studied using MTT solution and measured optical density on 570mm by ELISA reader. To measure the effects on the ability of whole protein and collagen synthesis, cell membrane was destructed with ultrasonic grinder after culturing, centrifuged and counted by liquid scintilation counter. The inhibitory effects on producing of $IL-l{\beta}$ by monocyte, after promotion of producing $IL-l{\beta}$ by LPS, were compared with the mixture of herbal extracts and other drugs using thymocyte stimulation assay. About inhibitory effects of $PGF_2$. by gingival fibroblasts, herbal extract was compared with the addition of the other control groups using enzyme imunoassay. On the inhibition of collagenolytic activity by P. gingivalis, benzene extracts showed the most efficient inhibitory effects among the $19{\mu}g/ml$ of the compared extracts and 40.5% by Tetracycline. On the cellular activity promoting effects, compared extracts showed a bit of more effects than PDGF of $100{\mu}g/ml$ concentration and IGF of $20{\mu}g/ml$ concentration. All of the PDGF, IGF, Zizyphi Fructus extract should increase in collagen synthesis, but especially 70% ethylalcohol extracts of Zizyphi Fructus showed comparably high effects among the compared extracts. Effects on whole protein synthesis were slightly increased on every extract but especially 70% ethylalcohol extract showed significantly effective than any other estract. On the inhibitory effects of Zizyphi Fructus $IL-l{\beta}$ production by monocyte, compared extracts showed 70% of highly inhibitory effect than that of 60% inhibition effects on controlled group and each extracts showed no significant difference. In $PGF_2$ production inhibitroy effect of Zizyphi Fructus gingival fibroblasts, Herbal extracts showed 70% of inhibition comparing with tat of 90.2% of controlled group, but each extracts showed similar effects excluding the $H_2O$ extracts. These results suggested that Zizyphi Fructus might be useful medicine for inhibition of inflammatory mediator including $IL-l{\beta}$ and $PGF_2$.

• Journal of Periodontal and Implant Science
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• 제27권1호
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• pp.165-177
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• 1997

The purpose of this study was to perform on the biological activity of Magnolia and Zizyphi fructus extract mixtures on the wound healing of defected rat calvaria. For the determination of the mixture ratio of two extracts for oral administration, preliminary experiments were performed with the mixture combination of 2000 and $3000{\mu}g/ml$ of Magnolia extract, and also 20, 30, 200, 300, 2000 and $3000{\mu}g/ml$ of Zizyphi fructus extract, respectively and divided into 6 groups. The combination of extracts mixture were tested on the enhancing effect of cellular activity. The effect of the extracts mixture on the cellular activity was evaluated using MTT method and measured on the results with optical density by ELISA reader. The ability to tissue regeneration of the extracts mixture was performed by measuring new bone and new connective tissue regeneration on the 5mm defected rat calvaria for 1, 2 and 3 weeks after oral administration of 2 different dosages groups : 10:1(0.1g/kg) and 10:1(0.5g/kg). It was employed the same dosages of unsaponifiable fraction of Zea Mays L as positive controls. Each group of rat was sacrificed and en bloc section for histological examination. The effect on the cellular activity of each mixture ratio showed significantly higher in $2000{\mu}g/ml$ of Magnolia extract and $200{\mu}g/ml$ of Zizyphi fructus extract group to compare with other groups. These preliminary results showed that appropriate mixture ratio of two extracts was 10:1 of Magnolia and Zizyphi fructus extract. Histological examination on the activity of tissue regeneration of each group showed that 2weeks and 3weeks specimens of 0.5g/kg of 10:1 extract mixture of Magnolia and Ziziphi fructus administrated rat calvaria revealed significantly more osteoid and new bone formation of defected calvaria with unification of defected area than the specimens of any other negative and positive controls. Even though the specimen administrated the same dosages of unsaponifiable fraction of Zea Mays L, positive controls, showed the trend that they promote significantly the repair of calvarial defect, their bone reparative activities were less inductive than the same dosages of Magnolia and Ziziphi fructus extract mixture. These results implicated that the mixture of Magnolia and Zizyphi fructus extracts should be highly effective on the wound healing of bony defected site and might have potential possibilities as an useful drug to promote periodontal tissue regeneration.

• 대한치과보철학회지
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• 제45권5호
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• pp.611-620
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• 2007

Statement of problem: Second-generation indirect composite resins have been improved flexural strength, compressive strength, hydrolytic degradation resistance, wear resistance compared to first-generation indirect composite resins, but there are still some problems as hydrolysis and low wear resistance. Some manufacturers claim that wear resistance of their materials has been improved, but little independent study has been published on wear properties of these materials and the properties specified in the advertising materials are largely derived from in-house or contracted testing. Purpose: This study was to evaluate the wear of indirect composite resins (SR Adore, Sinfony, Tescera ATL) and gold alloy against the human enamel. Material and method: Extracted human incisors and premolars were sectioned to $2{\times}2{\times}2mm$ cube and embedded in the clear resin and formed conical shaped antagonist to fit the jig of pin-on-disk tribometer. Total 20 antagonists were stored in distilled water. Five disk samples, 24mm in diameter and 1.5mm thick, were made for each of three groups of indirect composite resins and gold alloy group, and polished to #2,000 SiC paper on auto-polishing machine. Disk specimens were tested for wear against enamel antagonists. Wear test were conducted in distilled water using a pin-on-disk tribometer under condition (sliding speed 200rpm contact load 24N, sliding distance 160m). The wear of the enamel was determined by weighing the enamel antagonist before and after test, and the weight was converted to volumes by average density. The wear tracks were analyzed by scanning electron microscopy and surface profilometer to elucidate the wear mechanisms. Statistical analysis of the enamel wear volume, wear track depth and wear tract width of disk specimens were accomplished with one-way ANOVA and the means were compared for significant differences with Scheffe's test. Results: 1. The enamel wear was most in gold alloy, but there were no statistically significant differences among all the groups (P>.05). 2. In indirect composite resin groups, the group to make the most shallow depth of wear tract was Sinfony, followed by Tescera ATL, SR Adoro (P<.05). Gold alloy was shallower than Sinfony, but there was no statistically significant difference between Sinfony and gold alloy (P>.05). 3. The width of wear tract of SR Adore was larger than the other groups (P<.05), and there were no statistically significant differences among the other groups (P>.05). 4. SEM analysis revealed that Sinfony and gold alloy showed less wear scars after test, Tescera ATL showed more wear scars and SR Adore showed the most. Conclusion: Within the limits of this study, Sinfony and gold alloy showed the least wear rates and showed similar wear patterns.

• Journal of Periodontal and Implant Science
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• 제43권2호
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• pp.72-78
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• 2013

Purpose: The purpose of this study was to compare the phototoxic effects of blue light exposure on periodontal pathogens in both planktonic and biofilm cultures. Methods: Strains of Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum, and Porphyromonas gingivalis, in planktonic or biofilm states, were exposed to visible light at wavelengths of 400.520 nm. A quartz-tungsten-halogen lamp at a power density of $500mW/cm^2$ was used for the light source. Each sample was exposed to 15, 30, 60, 90, or 120 seconds of each bacterial strain in the planktonic or biofilm state. Confocal scanning laser microscopy (CSLM) was used to observe the distribution of live/dead bacterial cells in biofilms. After light exposure, the bacterial killing rates were calculated from colony forming unit (CFU) counts. Results: CLSM images that were obtained from biofilms showed a mixture of dead and live bacterial cells extending to a depth of $30-45{\mu}m$. Obvious differences in the live-to-dead bacterial cell ratio were found in P. gingivalis biofilm according to light exposure time. In the planktonic state, almost all bacteria were killed with 60 seconds of light exposure to F. nucleatum (99.1%) and with 15 seconds to P. gingivalis (100%). In the biofilm state, however, only the CFU of P. gingivalis demonstrated a decreasing tendency with increasing light exposure time, and there was a lower efficacy of phototoxicity to P. gingivalis as biofilm than in the planktonic state. Conclusions: Blue light exposure using a dental halogen curing unit is effective in reducing periodontal pathogens in the planktonic state. It is recommended that an adjunctive exogenous photosensitizer be used and that pathogens be exposed to visible light for clinical antimicrobial periodontal therapy.

• Journal of Periodontal and Implant Science
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• 제38권sup2호
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• pp.363-372
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• 2008

Purpose: This study compared the effects of coating implants with hydroxyapatite (HA) using an ion beam-assisted deposition (IBAD) method prepared with machined, anodized, sandblasted and large-grit acid etched (SLA) surfaces in minipigs, and verified the excellency of coating method with HA using IBAD. Material and Methods: 4 male Minipigs(Prestige World Genetics, Korea), 18 to 24 months old and weighing approximately 35 to 40 kg, were chosen. All premolars and first molars of the maxilla were carefully extracted on each side. The implants were placed on the right side after an 8 week healing period. The implant stability was assessed by resonance frequency analysis (RFA) at the time of placement. 40 implants were divided into 5 groups; machined, anodized, anodized plus IBAD, SLA, and SLA plus IBAD surface implants. 4 weeks after implantation on the right side, the same surface implants were placed on the left side. After 4 weeks of healing, the minipigs were sacrificed and the implants were analyzed by RFA, histology and histometric. Results: RFA showed a mean implant stability quotient (ISQ) of $75.625{\pm}5.021$, $76.125{\pm}3.739$ ISQ and $77.941{\pm}2.947$ at placement, after 4 weeks healing and after 8 weeks, respectively. Histological analysis of the implants demonstrated newly formed, compact, mature cortical bone with a nearby marrow spaces. HA coating was not separated from the HA coated implant surfaces using IBAD. In particular, the SLA implants coated with HA using IBAD showed better contact osteogenesis. Statistical and histometric analysis showed no significant differences in the bone to implant contact and bone density among 5 tested surfaces. Conclusion: We can conclude that rough surface implants coated with HA by IBAD are more biocompatible, and clinical, histological, and histometric analysis showed no differences when compared with the other established implant surfaces in normal bone.

• Journal of Periodontal and Implant Science
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• 제38권sup2호
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• pp.373-384
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• 2008

Purpose: The aim of this study is to compare the healing response of various Hydroxyapatite(HA) coated dental implants by Ion-Beam Assisted Deposition(IBAD) placed in the surgically created circumferential gap in dogs. Materials and methods: In four mongrel dogs, all mandibular premolars and the first molar were extracted. After an 8 weeks healing period, six submerged type implants were placed and the circumferential cylindrical 2mm coronal defects around the implants were made surgically with customized step drills. Groups were divided into six groups : anodized surface, anodized surface with 150nm HA and heat treatment, anodized surface with 300nm HA and heat treatment, anodized surface with 150nm HA and no heat treatment, and anodized surface with 150nm HA, heat treatment and bone graft, anodized surface with bone graft. The dogs were sacrificed following 12 weeks healing period. Specimens were analyzed histologically and histomorphometrically. Results: During the healing period, healing was uneventful and implants were well maintained. Anodized surface with HA coating and $430^{\circ}C$ heat treatment showed an improved regenerative characteristics. Most of the gaps were filled with newly regenerated bone. The implant surface was covered with bone layer as base for intensive bone formation and remodeling. In case that graft the alloplastic material to the gaps, most of the coronal gaps were filled with newly formed bone and remaining graft particles. The bone-implant contact and bone density parameters showed similar results with the histological findings. The bone graft group presented the best bone-implant contact value which had statistical significance. Conclusion: Within the scope of this study, nano-scale HA coated dental implants appeared to have significant effect on the development of new bone formation. And additional bone graft is an effective method in overcoming the gaps around the implants.

• Journal of Radiation Protection and Research
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• 제31권1호
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• pp.47-52
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• 2006

$0.3g/cm^3$ 에서 $1.5g/cm^3$까지 다양한 겉보기 밀도를 갖는 감마방출핵종 환경시료의 정확한 방사능 분석을 위해서 자체흡수보정(self-absorption correction)은 중요한 문제이다. 방사선 표준선원을 밀도별로 제작할 필요없이 마리넬리 비커를 감싸는 외부용기를 새롭게 제작하여 실용적이면서 간단한 자체흡수보정방법을 본 논문에서 제시하였다. 밀도 0.8, 1.0, $1.3g/cm^3$ 대해서 새로운 방법을 이용하여 자체흡수보정을 한 효율들과 밀도별로 직접 표준선원용액을 만들어 측정한 효율값이 4 % 이내에서 일치하였다.

• 한국과학교육학회지
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• 제22권3호
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• pp.560-570
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• 2002

이 연구에서는 대기압의 정의와 기압에 관련된 현상들에 대한 원리를 묻는 설문지를 개발하여 H대학교 석사 과정에 있는 94명의 과학 교사들에게 투입하여 일관되고 통합된 설명 체계를 갖고 있는 지를 알아보았다. 전공별로 구분하여 응답률을 비교하고 중등학교 과학 교과서, 대학 교재의 서술 방식과 교과들의 응답을 비교하였다. 연구 결과 첫째, 교과서와 대학 교재의 공기의 무게에 의한 압력이란 대기압의 정의에도 불구하고 화학 전공의 중학교 교사 지구과학 전공의 고등학교 교사는 중력과 분자 운동에 의한 압력으로, 화학 전공의 고등학교 교사는 기체의 분자 운동에 의한 압력이란 응답률이 상대적으로 높았다. 또한 고도에 따른 대기압의 변화를 공기 기둥의 무게로 설명하는 대부분의 교재에도 불구하고 이러한 응답을 한 교사는 절반에 불과하였다. 둘째, 대다수의 중등 교과서에서 저기압의 형성에 대해 대기압의 정의인 공기의 무게 개념을 적용하지 않고 가열되면 팽창하고 상승하여 밀도가 작아져 형성된다는 정확하지 않은 서술을 하고 있으며 대부분의 교사들도 밀도 개념으로 저기압의 형성을 설명하였다. 셋째, 교사들이 기압과 관련된 현상들을 교육과정에 의한 학생들의 선개념을 고려하여, 원리보다 현상만을 제시한 교과서의 서술 방식대로 응답하였다. 이러한 결과로부터, 대기압의 올바른 개념 형성을 위해서는 교과서의 내용 전개가 분자 운동, 중력, 힘의 평형, 대기압의 연계되어 구성되어야 할 것이며, 설명 체계 또한 명확하여야 할 것이다. 교사들의 기압에 관련된 개념들이 통합적으로 구성되어 있지 않은 것은 교과서나 교재의 영향이 크며 점진적이고 체계적인 개념 구조를 가지고 자연 현상을 통합적인 사고 과정으로 탐구하는 태도를 가질 수 있는 교사 교육이 필요함을 보여준다.

• 한국과학교육학회지
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• 제20권4호
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• pp.527-541
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• 2000

이 연구에서는 유치원 제 5차 교육과정과 초등학교부터 고등학교까지의 제 6차 과학교육과정에 근거한 교재들을 분석하고, 제시된 학습 내용의 전개 유형을 파악하고자 하였다. 구체척으로는 유치원부터 고등학교까지의 과학 교재에 제시된 '물질의 성질'에 관련된 학습 내용을 분석하였으며, 그 결과 학습 내용 전개 유형을 크게 5가지로 구분하였다. 즉, 개념의 확장 유형, 개념 수준의 심화 유형, 동일한 개념 수준 제시 유형, 다른 과학 개념과 뒤엉킨 유형, 학년간 혹은 학년 내 연계의 단절 유형으로 구분하였다. 이 중에서'개념의 확장 유형'과 '개념 수준의 심화 유형'은 학습 내용 전개가 바람직한 것이라고 판단할 수 있지만, 나머지 유형들은 부적절하다고 할 수 있다. 유치원부터 초등, 중등 과학 교재에서 공통적으로 다루는 '물질의 성질'에 관련된 7개의 개념을 중심으로 학습 내용 전개 유형을 분석한 결과, 바람직한 유형보다는 부적절한 유형이 더 많이 나타났다. 특히 '동일한 개념 수준 제시 유형'은 유치원과 초등학교 전반에 걸쳐서 광범위하게 나타났다. 그리고 바람직한 유형 중에서는 '개념의 심화 유형'보다는 '개념의 확장 유형'이 더 많은 것으로 분석되었다. 또한 '물질의 성질'에 관련하여 유치원부터 제시되는 많은 학습 개념이 중학교 1학년 이상에서 거의 다루지 않는 것으로 나타났다. 특히 이러한 특성을 가지는 개념들은 '개념의 심화 유형'으로 내용이 전개되지 않는 공통점이 있었다. 이러한 문제점들을 해결하기 위하여 과학 교재의 내용 구성에 대한 재고찰이 필요하다고 본다.

• 한국양식학회지
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• 제16권1호
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• pp.24-30
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• 2003

수정된 난은 분리침성란으로 저면에 침하하였으나, 해수의 유동에 의하여 쉽게 부상하는 성질이 있었다. 또 난의 모양은 완전한 구형으로 구경은 평균 150 $\mu\textrm{m}$ 정도였다. 각 발생 단계의 소요시간을 보면 8세포기까지 1.9시간, 상실기까지 7.9시간, 낭배기까지 27시간이 소요되었다. 담륜자 유생까지의 발생소요시간은 68시간이었는데 이 기간에는 섭이를 위해 활발하게 유영운동을 하였으며, 이때 유생의 체장은 평균63 $\mu\textrm{m}$였다. 평균체장 163 $\mu\textrm{m}$인 담륜자 유생이 7체절기로 성장하는데는 18일이 걸렸고, 13체절기까지의 소요시간은 29일었으며, 이 시기부터는 저면에서 연동운동에 의한 이동이 관찰되었다. 그리고 32일 경과시에는 평균체장은 768 $\mu\textrm{m}$인 치충으로 저질에 굴을 파고 잠입하였다. 60일 후 개불 치충의 평균체장은 1,108 $\mu\textrm{m}$였고, 90일 후에는 1.835 $\mu\textrm{m}$였으며, 체색은 투명하였다. 또한 120일 이후에는 평균체장이 3.7cm로 성장하였고, 체색은 적황색이었으며, 입 주위에 강모가 생성되어 완전한 성체의 모습을 갖추었다. 사육일수와 체장에 관한 상대성장식은 BL=0.2097 $e^{0.048}$4RD/ ($r^2$=0.9299)이었고(Fig. 2), 체장과 체폭의 상대성장식은 BB=0.2033BL-383.21($r^2$=0.9518)이었다. 저질선택성 실험개시 30일 경과 후, 펄에서 31마리, 조개껍질과 모래의 혼합구에서 23마리, 펄과 모래의 혼합구에서 21마리, 펄과 모래와 조개껍질의 혼합구에서 32마리가 관찰된 것에 반해 모래구에서는 한 마리도 관찰되지 않았다. 또한 개불의 잠입깊이 실험 결과, 2.5~5cm, 5~7.5cm구간에서 각각 10마리가 관찰되었다.