• Journal of Periodontal and Implant Science
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• v.46 no.6
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• pp.362-371
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• 2016

Purpose: The increasing demand for esthetically pleasing results has contributed to the use of ceramics for dental implant abutments. The aim of this study was to compare the biological response of epithelial tissue cultivated on lithium disilicate ($LS_2$) and zirconium oxide ($ZrO_2$) ceramics. Understanding the relevant physicochemical and mechanical properties of these ceramics will help identify the optimal material for facilitating gingival wound closure. Methods: Both biomaterials were prepared with 2 different surface treatments: raw and polished. Their physicochemical characteristics were analyzed by contact angle measurements, scanning white-light interferometry, and scanning electron microscopy. An organotypic culture was then performed using a chicken epithelium model to simulate peri-implant soft tissue. We measured the contact angle, hydrophobicity, and roughness of the materials as well as the tissue behavior at their surfaces (cell migration and cell adhesion). Results: The best cell migration was observed on $ZrO_2$ ceramic. Cell adhesion was also drastically lower on the polished $ZrO_2$ ceramic than on both the raw and polished $LS_2$. Evaluating various surface topographies of $LS_2$ showed that increasing surface roughness improved cell adhesion, leading to an increase of up to 13%. Conclusions: Our results demonstrate that a biomaterial, here $LS_2$, can be modified using simple surface changes in order to finely modulate soft tissue adhesion. Strong adhesion at the abutment associated with weak migration assists in gingival wound healing. On the same material, polishing can reduce cell adhesion without drastically modifying cell migration. A comparison of $LS_2$ and $ZrO_2$ ceramic showed that $LS_2$ was more conducive to creating varying tissue reactions. Our results can help dental surgeons to choose, especially for esthetic implant abutments, the most appropriate biomaterial as well as the most appropriate surface treatment to use in accordance with specific clinical dental applications.

• The Journal of the Korea Contents Association
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• v.10 no.3
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• pp.196-203
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• 2010

This study aimed to examine the effect of microcurrent stimulation on expression of Bone Morphogenetic Protein(BMP) 4 after tibia fracture in rabbits. The twenty four adult 6 month old New Zealand white rabbits weighting 2.5~3.5 ㎏ were used. Twenty four rabbits with tibia fracture were randomly divided into control and experimental groups. Each group was divided into four subgroups, based on the duration of the experiment (3, 7, 14, 28 days). The experimental groups received microcurrent stimulation of 20~25 ${\mu}A$ intensity with surface Ag-AgCl electrode (diameter 1cm, Biopac, U.S.A.) for 24 hours a day. Cathode of the microcurrent stimulator located on the tibia directly, anode of it did on the gastrocnemius muscle. After evaluation, the test results are as follows: Comparisons of immunohistochemical observation of BMP-4 in 7 days after tibial fracture show that there was shown to be a moderate positive reaction (++) on concentric circles of Harversian system and the interstitial lamella in the control group, while there was a very strong positive reaction () on concentric circles of Harversian system and interstitial lamellain the experimental group. These results suggest that applying non-invasive constant microcurrent stimulation on fractured bone is helpful to bone healing.

• Journal of Periodontal and Implant Science
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• v.29 no.4
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• pp.821-838
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• 1999

On the basis of the evidences that electrical stimulation could enhance proliferation and differentiation of bone cells and promote healing and regeneration of bone, this study was performed to investigate the effects of electrical stimulation on human periodontal ligament cells and gingival fibroblasts in vitro, which also have important roles in regeneration of periodontium, and to evaluate the potential of clinical application of electrical stimulation. Human periodontal ligament cells and gingival fibroblasts were primarily cultured from the root surface of extracted premolar and the adjacent gingiva without periodontal diseases. In control group, the cells ($5{\times}10^4$ cells/ml)were incubated only in Dulbecco's Modified Eagle's Medium contained with 10% fetal bovine serum. In test groups, electrical stimulation was given at the current intensity of $0.25{\mu]A$(test group 1), $1.0{\mu}A$(test group 2), and $2.5{\mu}A$(test group 3) for 12 hours to the same culture media with the control group. After 12 hour exposure of electrical stimulation, the cells were incubated for 2 and a half days(60 hours), and then each group of cells was analyzed for cell proliferation, protein level, and activity of alkaline phosphatase. The results were as follows ; 1. The Rate of cell proliferation of every test group increased significantly in both periodontal ligament cells and gingival fibroblasts, and in periodontal ligament cells, test group 3 showed significantly increased proliferation compared to the other test groups(p<0.05). 2. In the protein levels, neither periodontal ligament cell nor gingival fibroblast showed statistically significant differences between control and test groups. 3. The activity of alkaline phosphatase in periodontal ligament cells increased significantly in all test groups(p<0.05), but there were no significant differences between 3 test groups. In gingival fibroblasts, the activity of alkaline phosphatase increased significantly only in test group 3(p<0.05). From the above results, it is concluded that electrical stimulation may have beneficial effects on the regeneration of destructed periodontal tissue in regard of the stimulation of periodontal ligament cells and gingival fibroblasts as well as electrically stimulated bone formation that has been known, and that electrical stimulation may have the potential of clinical application.

• Korean Journal of Food Science and Technology
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• v.48 no.6
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• pp.531-535
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• 2016

Phlomis umbrosa and Dipsacus asperoides are distinct species, even though they have a similar appearance. Dipsacus asperoides is used as a Chinese medicinal plant for and has bone strengthening and fracture healing but Phlomis umbrosa has no effect on bone growth. Recently, these plants were used in children's food to improve their bone growth, without distinction in food. Intakes of Dipsacus asperoides in food may be dangerous, because it has never been used in food and its safety has never been tested in humans. We developed liquid chromatography with tandem mass spectrometry method to distinguish these plants in food. The method was validated for linearity, limits of detection, limits of quantification, accuracy and precision. In 5 of 17 samples, we identified Dipsacus asperoides, containing loganin $0.19-14.45{\mu}g/mL$, sweroside $0.13-4.61{\mu}g/mL$ and akebia saponin D $0.59-19.29{\mu}g/mL$. The developed method might be useful to identify Dipsacus asperoides in adulterated food.

• Journal of Dental Rehabilitation and Applied Science
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• v.25 no.1
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• pp.41-52
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• 2009

The surface treatment of titanium implant could bring out the biochemical bonding between bone and implant. The purpose of this study was to evaluate the biomechanical bone response of Mg-ion implanted implants with plasma source ion implantation method. Twelve New Zealand white rabbits were included in this study. Each rabbit received one control fixture (blasted with resorbable blasting media, RBM) and three types of Mg ion implanted fixtures in tibiae. The implants were left in place for 6 weeks before the rabbits were sacrificed. Removal torque value and resonance frequency analysis (ISQ) were compared. The repeated measured analysis of variance was used with $P{\leq}0.05$ as level of statistical significance. ISQ was not different among all groups. However, the ISQ was increased after 6 weeks healing. The group had lowest ISQ value showed the greatest increment. Mg-1 implants with 9.4% retained ion dose showed significantly higher removal torque value than that of the other implants. From this results, it is concluded that the Mg-1 implants has stronger bone response than control RBM surface implant.

• Journal of Periodontal and Implant Science
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• v.35 no.4
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• pp.949-959
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• 2005

이 연구는 임플란트를 식립하기를 원하는 전신건강상태가 양호하며 구강위생상태가 좋은 14명 환자(남자:8명, 여자:6명, 평균나이 : 44세)의 20개의 발치와 내에 흡수성 차폐막(BioMesh. Sam Yang Corporation, Korea)과 함께 탈회냉동 건조동종 골(dem-ineralized freezedried bone allografts, $250-500{\mu}m$. Pacific Coast Tissue Bank, U.S.A.)과 이종골(Bovine-Bone, Bio-Oss 0.25-1.0 mm, Geistlich, Biomaterials and Osteohealth, Switzerland)을 1:1(부피)로 혼합하여 이식한 후 그 치유양상을 관찰하고자 조직학적 및 면역조직화학적으로 평가하였다. 이직재가 탈락되는 것을 방지하기 위하여 발치한 후 1개윌이 경과된 후에 이식재와 차폐막을 위치시켰다. 표본제작을 위하여 이식술을 시행한 지 약 6개윌 후에 임플란트를 식립하기 직전 식립부위에서 trephine bur로 골을 채취하였는데, 20증례 중 7증례에서 임플란트를 식립하기 전에 차폐막이 노출되었다. 차폐막이 노출되지 않은 것을 대조군으로, 노출된 것을 실험군으로 설정하였다. 조직학적인 관찰을 위하여 통상적인 방법에 따라 탈회 표본을 제작하였고, alkaline phosphotase(ALP)틀 이용하여 면역조직화학적 염색을 시행한 후 골 형성 상태를 평가하여 다음과 같은 결과를 얻었다. 본 연구에서는 발치와내에서 골유도재생술 후 나타나는 치유 형태를 5가지 형태로 분류할 수 있었다. Type I, II와 III는 새로운 골 형성을 나타내지 않았고, 면역조직화학적 검사 시 ALP 음성 소견을 나타내었다. Type V는 새로운 골 형성과 ALP 양성 소견을 나타내었으나 염증, 괴사, 결합조직의 증식 등은 없었다. Type IV와 Type V의 차이는 결합조직의 증식여부로 구분되었다. 막이 노출되지않은 증례들 중 7 증례에서는 Type V의 치유 형태를, 2증례에서는 Type IV의 치유 형태를 나타내었다. 막이 노출되었던 증례에서는 Type I, II, III의 다양한 치유 형태를 나타내었다. 본 연구결과, 발치와 내에 골유도재생술을 시행한 후 차폐막의 노출 여부가 신생골 형성에 중요한 영향을 미칠 것으로 사료되며, 본 연구에서 분류한 치유 형태가 향후 골유도재생술 후의 결과 분석에 활용될 수 있을 것으로 사료된다.

• The Journal of Korean Academy of Prosthodontics
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• v.41 no.3
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• pp.300-318
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• 2003

Statement of problem: The success of implants depends on intimate and direct contact of implant material on bone tissue and on functional relationship with soft tissue contact. Creation and maintenance of osseointegration depend on the understanding of the tissue's healing, repairing, and remodeling capacity and these capacities rely on cellular behavior. Altering the surface properties can modify cellular responses such as cell adhesion, cell motility, bone deposition, Therefore, various implant surface treatment methods are being developed for the improved bone cell responses. Purpose: The purpose of this study was to evaluate the responses of osteoblast-like cells to surface-modified titanium. Materials and Methods: The experiment was composed of four groups. Group 1 represented the electropolished surface. Group 2 surfaces were machined surface. Group 3 and Group 4 were anodized surfaces. Group 3 had low roughness and Group 4 had high roughness. Physicochemical properties and microstructures of the discs were examined and the responses of osteoblast-like cells to the discs were investigated. The microtopography was observed by SEM. The roughness was measured by three-dimension roughness measuring system. The microstructure was analyzed by XRD, AES. To evaluate cell responses to modified titanium surfaces, osteoblasts isolated from calvaria of neonatal rat were cultured. Cell count, morphology, total protein measurement and alkaline phosphatase activities of the cultures were examined. Results and Conclusion: The results were as follows 1. The four groups showed specific microtopography respectively. Anodized group showed grain structure with micropores. 2. Surface roughness values were, from the lowest to the highest, electropolished group, machined group, low roughness anodized group, and high roughness anodized group. 3. Highly roughened anodized group was found to have increased surface oxide thickness and surface crystallinity. 4. The morphology of cells, flattened or spherical, were different from each other. In the electropolished group and machined group, the cells were almost flattened. In two anodized groups, some cells were spherical and other cells were flattened. And the 14 day culture cells of all of the groups were nearly flattened due to confluency. 5. The number of attached cells was highest in low roughness anodized group. And the machined group had significantly lower cell count than any other groups(P<.05). 6. Total protein contents showed no difference among groups. 7. The level of alkaline phosphatase activities was higher in the anodized groups than electropolished and machined groups(P<.05).

• Journal of Periodontal and Implant Science
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• v.37 no.2
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• pp.223-236
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• 2007

This study was attempted to evaluate home-manufactured implants by placing $Stage-1^{(R)}$ Implant (Lifecore, Co., USA) whose surface is treated with REM that has already been varified clinically,$Chaorum^{(R)}$ Implant(Chaorum Co., Korea) whose surface treatment is same as that of Stage-1 Implant and $Atlas^{(R)}$ Implant(Cewellmedi Co., Korea) whose surface is treated with anodic oxidation immediately after the teeth of experimental animals were extracted to compare histological findings among them. Stage-l Implant(diameter: 3.5mm, length: IOmm), Chaorum Implant(diameter: 3.3mm, length: 8.5mm) and Cowell medi Implant(diameter: 4.0mm, length: 8.0mm) were placed into the mandible premolars of 2 adult beagle dogs immediately after their teeth were extracted, and then histological findings were analyzed at 6 weeks. After those implants were inserted directly after their teeth were extracted, the results of periotest were recorded, radiography was done, the subjects went through thorough control for 6 weeks, and then comparison among periotest, radiography and histological finding was made. After comparison of those findings, the values of periotest were satisfactory and bone healing was relatively satisfactory on radiography at 6 weeks. For osseointegration with the bone tissue, Stage-1 was 45.3%, Chaorum 55.3%, and Cowellmedi 52.5%, which was a satisfactory result. Although implant surgery immediately after teeth were extracted involves difficulties among recent implant surgeries, it is being frequently used in that it may reduce surgery hours, the frequency of surgery, and bone loss for patients. This experiment was conducted to evaluate the technological levels of home-manufactured implants that have been remarkably developed in recent years and in conclusion, those implants showed nearly similar result.

• Journal of Korean Foot and Ankle Society
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• v.23 no.2
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• pp.58-66
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• 2019

Purpose: To evaluate the efficacy of antibiotic-loaded cement spacers (ALCSs) for the treatment of diabetic foot infections with osteomyelitis as a salvage procedure and to analyze the risk factors of treatment failure. Materials and Methods: This study reviewed retrospectively 39 cases of diabetic foot infections with osteomyelitis who underwent surgical treatment from 2009 to 2017. The mean age and follow-up period were $62{\pm}13years$ and $19.2{\pm}23.3months$, respectively. Wounds were graded using the Wagner and Strauss classification. X-ray, magnetic resonance imaging (or bone scan) and deep tissue cultures were taken preoperatively to diagnose osteomyelitis. The ankle-brachial index, toe-brachial index (TBI), and current perception threshold were checked. Lower extremity angiography was performed and if necessary, percutaneous transluminal angioplasty was conducted preoperatively. As a surgical treatment, meticulous debridement, bone curettage, and ALCS placement were employed in all cases. Between six and eight weeks after surgery, ALCS removal and autogenous iliac bone graft were performed. The treatment was considered successful if the wounds had healed completely within three months without signs of infection and no additional amputation within six months. Results: The treatment success rate was 82.1% (n=32); 12.8% (n=5) required additional amputation and 5.1% (n=2) showed delayed wound healing. Bacterial growth was confirmed in 82.1% (n=32) with methicillin-resistant Staphylococcus aureus being the most commonly identified strain (23.1%, n=9). The lesions were divided anatomically into four groups; the largest number was the toes: (1) toes (41.0%, n=16), (2) metatarsals (35.9%, n=14), (3) midfoot (5.1%, n=2), and (4) hindfoot (17.9%, n=7). A significant difference in the Strauss wound score and TBI was observed between the treatment success group and failure group. Conclusion: The insertion of ALCSs can be a useful treatment option in diabetic foot infections with osteomyelitis. Low scores in the Strauss classification and low TBI are risk factors of treatment failure.

• Implantology
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• v.18 no.2
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• pp.120-138
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• 2014

Purpose: The purpose of this study was to review the outcomes of a series of studies on tissue regeneration conducted in multiple institutions including the Department of Periodontology, College of Dentistry, Yonsei University. Materials and Methods: Studies were performed divided into the following three subjects; 1) Development of three-dimensional nano-hydroxyapatite (n-HA) scaffold for facilitating drug release and cell adhesion. 2) Synergistic effects of bone marrow-derived mesenchymal stem cells (BMMSC) application simultaneously with platelet-rich plasma (PRP) on HA scaffolds. 3) The efficacy of silk scaffolds coated with n-HA. Also, all results were analyzed by subjects. Results: Hollow hydroxyapatite spherical granules were found to be a useful tool for the drug release and avidin-biotin binding system for cell attachment. Also, BMMSC simultaneously with PRP applied in an animal bone defect model was seen to be more synergistic than in the control group. But, the efficacy of periodontal ligament cells and dental pulp cells with silk scaffolds could not be confirmed in the initial phase of bone healing. Conclusion: The ideal combination of three elements of tissue engineering-scaffolds, cells and signaling molecules could be substantiated due to further investigations with the potentials and limitations of the suggested list of studies.